The research presented in this paper is subject to RC frame that increases seismic capacity by attaching DT(Double T type) steel frame to reinforced concrete column. The object of this study is not only to build experimental database providing necessary information for retrofit column but also to formulate modeling parameters of RC frame retrofitted by DT steel frame through comparing analysis for analytical model predicting inelastic behavior of reinforced concrete members.

The government of South Korea enacted Earthquake Recovery Plan Act in 2008. In order to meet the requirement of this law, the important buildings, such as schools, public offices and so on, are in the process of seismic retrofit. This paper introduces the experimental data about a non-retrofitted concrete column and retrofitted column with a bolt assembly type CFT(concrete-filled steel tube).

In this study, the electrical conductivity and shielding effect were evaluated according to the type of metal and the thickness of Metal sprayed coating. The metals used for the test are Cu, Cu-Ni and Cu-Zn, and the thicknesses were 100, 200, 500 um. Each metal sprayed coating was evaluated for electrical conductivity and electromagnetic shielding effect. When the thickness was 200 ㎛ or more, shielding effect 80 dB or more was satisfied at 1 GHz. However, in the case of Cu-Ni, there is little electrical conductivity at a thickness of 100 um or less due to the generated voids, and electromagnetic wave shielding performance cannot be expected. Therefore, To ensure electromagnetic shielding effect of structures, it is considered that the minimum thickness of metal spraying coating should be 200 um.

Currently, the most used forms, such as euro form and aluminum form, has many problems. There are issues with noise of construction site because of existing forms' material and issues with safety because of heavy weight. To solve these problems, there are many researches on using plastic and composite materials on the formwork. However, plastic has lower tensile strength than the steel and aluminum and composite materials are expensive. Therefore, constructors are avoid to use the forms with new materials. The purpose of this study is to develop light-weight plastic form to solve these existing problems by using ABS with optimized design. To verify, the study measured the amount of deflection from developed form through a load test. The test result showed a deflection of 1.15mm when 1.4ton was loaded in the middle of form. The result of the study verified that the usage of ABS and optimized design effectively reduced the weight and noise. Also, it's performance was verified through the load test.

Construction projects and buildings are becoming taller and larger, and the size of water tanks of production facilities and high-rise buildings is also gradually increasing. Most large water tanks apply a waterproofing layer to the water tank type concrete structure. The application of polyurea coating materials, which are excellent in water resistance, chemical resistance, physical performance, rapid hardening, and workability is gradually increasing as waterproofing and anticorrosion layer for water tank. As a result, defects such as water leakage and damage to the waterproofing layer are continuously occurring, causing production disruption, setback to users. Therefore, it is required to review suitability through performance verification of the waterproofing and anticorrosion system.

The need for off-site construction has increased in the construction industry in Korea in recent years due to the enforcement of the 52-hour workweek, the increasing age of workers on construction sites, the deepening dependence on overseas workers, and the stagnation of productivity in the construction industry. Thus, studies on OSC started in April 2020. In addition, as a national policy study advocating the modular construction method, which is one of the OSC methods, was completed in the first half of 2019. 70 housing units in two complexes that satisfied the Housing Act requirements have been supplied to citizens. However, although modular construction methods have been recognized as a dramatic construction method that achieves shortened construction schedules and solves the issues of cost reduction and the shortage of technical workers on sites by combining the advantages of the manufacturing industry and applying the economies of scale, realistically it has issues due to the rising cost of steel and a low pre-fabrication ratio. Moreover, the construction time of core parts, such as those built by pouring concrete, has become a factor that hinders the shortening of construction times. Thus, this study aims to propose a precast concrete(PC) modular construction system, which fuses three-dimensional infill as an interior finish material and a three-surface PC module that can acts as a structure for a construction method that is economical and can shorten construction time.

In this paper, we intended to present a model for estimating carbon dioxide emissions by work of construction equipment using Artificial Neural Network(ANN) analysis. In this study, data of excavators and trucks are classified according to the work carried out, and carbon dioxide emissions are predicted through ANN based on equipment information and work information. As a result, the effect of each model was validated, and a carbon dioxide emission prediction model was derived for each work. This has the expected effect of establishig an eco-friendly process plan using this model from the construction planning stage.

Domestic and foreign high-rise buildings are expected to continue to increase in the future. In addition, recently, residents and landlords are demanding maintenance necessary to secure the performance of sustainable buildings, so an effective management plan is needed. Therefore, this study aims to develop customized technologies that can be effectively applied to building structures by comprehensively analyzing existing technology-based research cases. As a result, it is expected that this will serve as a stepping stone to present a s+ample of future technology development along with a reduction in labor dependency on maintenance and quality improvement.

In this study, the pile filling materials of the pile in drilled piling was studied. cement milk is mostly used as the filling materials of bored pile. The use of filling material based on cement milk is inefficient at field construction because it needs a lot of the charging mass. thickening agent was added to the cement milk to perform settlement estimation experiment on a circular cylinder, and as a result of examining the compressive strength of the day, it was found that the settlement estimation was significantly reduced. However, the strength was relatively low, it was confirmed that there was no problem with the regulation because the main surface fixative required relatively low strength.

In this study, the concrete compressive strength estimation system Concrete IoT Management System (hereinafter referred to as CIMS) was developed, and CIMS was applied to domestic field structure slabs and wall concrete to check whether CIMS is practically available and to estimate the accuracy of the initial strength estimation of concrete. As a result, it shows a very high correlation when the compressive strength of the specimen for structural management is compared with the estimated strength of CIMS in terms of integrated temperature, and it is expected to be gradually applied to domestic construction sites in the future.

In this study, by applying the concrete compressive strength estimation system Concrete IoT Management System (hereinafter referred to as CIMS) to the concrete slab concrete in the domestic field, the purpose of this study is to confirm the practical use of CIMS and to verify the accuracy of estimating the initial strength of concrete. As a result, it shows a high correlation when the compressive strength and CIMS estimated strength of the specimen for structural management are converted and compared with the integrated temperature. However, in order to determine a more accurate experimental constant, it is necessary to consider the results up to 28 days.

In this study, as a measure to recycle red mud, which is a byproduct of the Bayer Process, red mud was manufactured as liquid and recycled without drying and grinding. Previous studies have shown that mechanical performance decreases when liquid red mud is applied to cement concrete. Therefore, in this study, liquid red mud was neutralized with nitric acid and applied to cement paste to examine the properties of cement paste according to the addition of red mud. As a result, the compressive strength of 10% liquid red mud decreased by 37.7% compared to Plain, and 10% liquid red mud indicates similar strength to Plain and restores the strength.

As the modern society enters, the building becomes sealed and the public's interest in the environment increases, so the interest in indoor air pollution increases and the environmental pollution is raised as an important issue not only outdoors but also indoors. In addition, the emergence of sick house syndrome (SHS) has increased the interest in formaldehyde and is a cause of deteriorating indoor air quality. Accordingly, this study prepared a functional paint by incorporating a photocatalyst in an aqueous paint, and conducted formaldehyde adsorption experiments and functional evaluation. As a result of the experiment, as the photocatalyst was added, the formaldehyde adsorption performance tended to increase. In addition, as a result of measuring the impact resistance and alkali resistance according to the KS standard, there is no difference in residual cracks and cracks between the water-based paint without the photocatalyst and the water-based paint with the photocatalyst added. Therefore, it is considered that the water-based paint added with a photocatalyst can improve the indoor air quality by adsorbing formaldehyde and can be used as a functional paint because the functionality is not different from that of a general water-based paint.

Concrete changes its internal moisture distribution depending on the external environment, and changes in the condition of the material's interior over time affect the performance of the concrete. These effects are closely related to the long-term behavior and durability of concrete, and the degree of deterioration varies from climate to climate in each region. In this study, we use actual climate data from each region with distinct climates. A multi-physical analysis based on the method was conducted to predict the difference and degree of deterioration rate by climate.

Unit-water content is an element directly related to durability and unit-water content of concrete used at construction site has a great effect on the durability of construction structure. Many methods are being discussed for more convenient and accurate measurements of unit-water content. Therefore, an experimental study was conducted on the prediction of unit-water content using ultrasonic equipment. Depending on the amount of cement in cement paste, the speed of ultrasonic waves varies and the experiment will be carried out using the same reception sensitivity in the future.

The government seismic retrofit project for educational facilities is progressing more actively due to the 2018 Pohang earthquake. It is most important that seismic retrofit constructions are conformed to seismic design to achieve the desired purpose of the project as reduce direct damage caused by earthquake. However, the construction supervision system is not mandatory for the retrofit construction site of small buildings including school buildings according to applicable laws and regulations. The purpose of this study was to develop a guide for constructions management of school building seismic retrofit. In order to achieve this goal, the survey on the construction site was conducted and various problems related to the construction site of school building seismic retrofit was derived Additionally, the systematic checklist was presented according to the user and seismic reinforcement method.

Currently, attempts are being made to introduce innovative teaching methods in architectural engineering education. However, there is still a lack of research supporting self-directed learners. In this regard, this study sought to develop an application prototype to support learning from online lectures on architectural engineering and conduct prototyping for its evolution. Menus in the application prototype consisted of four main categories: lecture operation, video lectures, eBooks and past exam questions. The lecture operation was classified into eight sub-categories, including assignment submission and notice, so as to support interactions between instructors and learners as well as confirmation of the delivery methods. With respect to video lectures, assignment submissions and notice functions, prototyping connecting the mobile web was implemented to enhance user convenience.

As the capacity of the 3d scanner developed, the reverse engineering using the 3d scanner is emphasized in the construction industry to obtain the 3d geometric representation of buildings. However, big size of the indoor point cloud data acquired by the 3d scanner restricts the efficient process in the reverse engineering. In order to solve this inefficiency, several pre-processing methods simplifying and denoising the raw point cloud data by the rough standard are developed, but these non-standard methods can cause the inaccurate recognition and removal the key-points. This paper analyzes the correlation between the accuracy of wall recognition and the density of the data, thus proposes the proper method for the raw point cloud data. The result of this study could improve the efficiency of the data processing phase in the reverse engineering for indoor point cloud data.

Recently as construction projects have been complicated, it has been wearing thin to draw on their personal experiences for management. Although the advance of IT, using the technology for construction is insufficient in contrast to other industries. BIM has been steadily used in construction projects, but it is not easy to find the case of successful use. This research considers ways in which BIM technology can be applied to useful management on a construction site and derives a method of application of using BIM for a Mega-complex Building Project especially.

Korea has the fourth highest CO₂ emission among OECD countries in 2018, As of 2019, total greenhouse gas emissions per capita increased by about 98.2% in comparison to 1990. Korea has promised a 37% reduction in greenhouse gas emissions in 2030 from the projected Paris Climate Change Accord. Currently, many countries use the emissions trading system(ETS) for international carbon management. In 2015, ETS has been implemented in Korea, and the importance of calculating CO₂ emissions from construction machinery has increased. So, we require an accurate calculation of the environmental charges through the allocated CERs. Using the CER price and related search keywords, this paper derive about prediction models of CER price and compare and focus on more accurate prediction about CER price. By this method, the budget needed to establish the initial construction process plan can be calculated based on more accurate predicted CER price.

Now a days, Lots of research about 4th industrial revolution are progressing. Attempt of technologies on construction engineering field, such as construction management by drone, building equipments based on the IoT technology and etc., are continuously tried by government and private enterprises. Meanwhile, the application of advanced technologies on the military facilities should be reviewed cautiously, because of the national defense environment such as military security. Therefore, this study aim to understanding of present status of military facilities for introduction of 4th industrial revolution technology. To achieve the aim of the study, question investigation targeting working groups for military facility management is conducted.

Recently the diversification of construction market and the continuous reduction of construction amount are raising the need of alternative delivery method in the construction industry. The foreign advanced companies actively adopted the CM at Risk delivery method where they perform the service of agent CM in the design phase, and agree GMP(Guaranteed Maximum Price) with the client at the time of 50~80% completion of design. Even in Korea they began to apply that method to pilot projects. In CM at Risk, through the early participation of builder, the level of design completion can be improved and the change order and construction period delay can be minimized. On the other hand, GMP is usually calculated when the design is about 80% complete, so there is uncertainty in the construction cost. Therefore, in this research, the increased amounts of construction cost are analyzed in a number of public construction projects, and GMP calculation process is proposed using the analysis results and CBR(Case-Based Reasoning) technique to reduce the construction cost increase in the construction phase.

Recently, construction projects are gradually becoming high-rise and large-scale, and furthermore, the use of new buildings is emerging through the deepening of the underground. In this situation, a lot of fire damage has occurred in recent years, mainly in buildings and tunnel structures. In particular, damages caused by fires during large-scale construction projects such as freezing warehouse accidents are increasing. In this situation, in Korea, it is still trying to secure safety from human fire through the administrative system divided into the building law and the fire law, but it is being developed in a negative direction rather than a positive direction. The fire risk is getting bigger even when the road is not maintained. In this current situation, it is considered that the development of a Korean integrated life safety code centering on the consciousness base of Koreans will be necessary, and in particular, the ease of revision will also be needed by promoting the integrated safety code rather than current laws and regulations. This is a summary of the future tasks.

Recently, "The rules on the standards of evacuation and fire protection of buildings" require that non-burnable materials such as non-combustible and semi-non-combustible materials be used as the materials applied to the building's exterior walls, but styrofoam, which is a combustible material, has been applied a lot and became a social issue. In this study, we developed a non-combustible outer wall molding to secure construction and economic feasibility and free expression using CLC(CLC: Cellular Light-weight Concrete).

The purpose of this study is to achieve a sufficient fluidity without segregation for normal compressive strength grade concrete mixture. The major obstacle of achieving fluidity of normal compressive strength grade concrete mixture is segregation. Hence, in this research, VMA was used to prevent segregation.

The change of temperature and humidity in early-age concrete has a great influence on the durability of the structure. In this study, a reliable wireless sensor network system and a concrete embedded type Compressive strength prediction sensor were designed using the Arduino platform. The accuracy of the compressive strength prediction sensor was verified through a mock-up experiment, and it was confirmed that the experiment had sufficient accuracy to be used in the field environment.

In this study, the recycled fine aggregates produced from the waste concrete by using Jaw crusher depending on crushing gap of Jaw crusher were studied to offer a solution for recycled fine aggregate for concrete. The results of the experiment showed that the factors that influence grading and water absorption ratio, density and grain shape were significantly characterized by the generation of the particulate matter and the crushing shape of the aggregate.

In this study, fundamental properties of high strength concrete containing blast furnace slag are investigated analyzed according to CBS-Dust replacement rate. As the CBS-Dust replacement rate increased, air content, fluidity and strength decreased, but concrete with 5~10 % of CBS-Dust showed excellent compressive strength in its early age. Therefore, 5~10 % substitution of CBS-Dust on high strength concrete containing blast furnace slag will have a positive effect on reducing waste disposal cost and improving the strength.

Oyster shells are difficult to grind, while oyster shell powders have coarse and coarse grains, whereas egg shell powder, the same high calcium material, has small and soft particles and has opposing properties. In order to study the change in flexural and compressive strength by designing different mixing ratios using 50% of oyster shell powder and egg shell powder as a filling material. As a result of the experiment, there is almost no difference in the result.

The synthesis of stearic acid composite phase change material (PCM) was investigated and the samples produced were characterized for use in latent heat storage, using a simple chemical sol-gel process. The PCM was encapsulated to tetraethyl orthosilicate by various preparation ratios of stearic acid (5, 10, 15, 20, 30 and 50%). Fourier transformation infrared spectroscope (FT-IR) and X-Ray diffraction (XRD) were performed to determine the chemical structure and crystalloid phase of the microencapsulated PCM. SATEOS1 (5%) shows the best proportion for the PCM. With the presence of stearic acid as core materials and SiO2 as the supporting materials, it does not show any chemical reaction between both of them. SATEOS1 shows promising potential for thermal energy storage as it shows a better encapsulation efficiency and good thermal stability.

Recently, the problem of air pollution is drawing attention as a social problem worldwide. Particularly, fine dust is the biggest issue among air pollutants, and it is analyzed that fine dust is generated from air pollutants such as burning fossil fuels such as petroleum or coal, or exhaust gases from automobiles. In addition, yellow dust originating from China adjacent to Korea flows into the Korean Peninsula in a western wind, causing the concentration of fine dust to deteriorate. Fine dust is a harmful substance to the human body such as asthma or respiratory disease, and awareness of the risk is also increasing to a degree designated as a primary carcinogen. In this study, as a method for improving the indoor air quality, the Properties of the matrix according to the mixing ratio of powdered activated carbon based on blast furnace slag are reviewed. The flexural strength and compressive strength were measured, and a fine dust concentration measurement experiment will be conducted later.

γ-dicalcium silicate (γ-C2S) is characterized by its strong carbonation reactivity and has the prospect to be utilized as a building material with the added benefit of CO2 capture. This paper aims to point out the impact of γ-C2S on the microstructure characteristics and mechanical properties of GGBFS paste, and mortar samples. Three curing conditions including un-carbonation, natural carbonation, and accelerated carbonation were applied to the research. Besides, hydration products after the carbonation process are also detected. What's more, the carbonation treatment method also meets the requirement of capture more greenhouse gas and recycles the waste products of metallurgy.

In this study, the feasibility of the durometer into super retarding concrete was studied by comparing the penetration resistance with the hardness of each durometer using the penetration resistance and the improved Durometer and Durometer A-Type according to the ultra-delay mixture rate. The test results showed that initial setting time by improved Durometer and Durometer A-Type were fixed at 25, 50 HD, respectively, and the 35, 80 HD showed at final setting time. It was also found that the use of the durometer can be available to measure the setting time of the concrete.

Use fire resistant construction methods, of which fire resistant boards are used to protect buildings and structures from fire. However, in the case of fire resistant boards, the unit price of the main raw material is high and the cost efficiency is low. There have been studies to apply oyster shells to fire resistant boards to solve these problems. On the other hand, egg shells are also considered to be applicable to fire-resistant boards with components like oyster shells, but there is no case of using egg shells as building materials. Therefore, in this study, we confirmed the physical properties of egg shell powers used as mortar filler and compared them with the fire resistant board flexural strength standard. As a result, it was judged that the powder of egg shells could be used as a building material, because the standards for the flexural strength of fire resistant boards were satisfied except for a part.

In Korea, more than 30,000 tons of waste Styrofoam are produced every year. Styrofoam is spent more than 500 years decomposing during the reclamation process, so it needs to be recycled. The recycling rate of waste styrofoam continues to be the third highest in the world, but it is lower than that of Germany and Japan. Therefore, measures are needed to increase the recycling rate of waste Styropol. Another problem is that cement is mainly used in existing lightweight foam concrete. However, large amounts of CO2 from cement-producing processes cause environmental pollution. Currently, Korea is increasing its greenhouse gas reduction targets to cope with energy depletion and climate change, and accelerating efforts to identify and implement reduction measures for each sector. In 2013 alone, about 600 million tons of carbon dioxide was generated in the cement industry. Therefore, this study replaces CO2 generation cement with furnace slag fine powder, uses crude steel cement for initial strength development of bubble concrete, and manufactures hardening materials to study its properties using waste styrofoam. As a result of the experiment, the hardening agent replaced by micro powder of furnace slag was less intense and more prone to absorption than cement using ordinary cement. Further experiments on the segmentation and strength replenishment of furnace slag are believed to contribute to the manufacture of environmentally friendly lightweight foam concrete.

The class-C fly ash (FA) and ground granulated blast-furnace slag (GGBS) based geopolymer activated in NaOH (4M) was studied regarding compressive strength, porosity, microstructure and formation of crystalline phases. The class-C FA and GGBS blends resulted in reduced strength and increased porosity of the matrix with the increase in FA content. The unreactivity of calcium in blends was observed with increasing FA content leading to strength loss. it is evident from XRD patterns that calcium in FA did not contribute in forming CSH bond, but formation of crystalline calcite was observed. Furthermore, XRD analyses revealed that reduction in FA leads to the reduction in crystallinity and SEM micrographs showed the unreactive FA particles which hinder the formation of denser matrix.

In this study, after applying a silicate-based impregnation and polymer-based coating to fire damaged high strength concrete, carbonation resistance was evaluated to compare and evaluate the carbonation depth according to the type of surface repair materials. As a result of the experiment, it was confirmed that the carbonation resistance was increased in the case of the concrete with the surface repair materials compared to the control specimen without the surface repair materials. In particular, in the case of the polymer-based coating agent, it was confirmed that the carbonation hardly progressed.

In present study, we have deposited the Zinc coating using arc thermal spray and plasma arc spray processes onto the steel substrate and durability of the deposited coating was evaluated. The bond adhesion result shows that plasma arc sprayed Zn coating exhibited higher in its value compared to arc thermal spray. SEM shows that Zn coating deposited by plasma arc process is more compact, less porous and adherent compare to arc spray process. The corrosion resistance properties are evaluated in artificial ocean water solution with exposure periods. EIS results show that total impedance at 0.01 Hz of plasma arc sprayed coating is higher than arc thermal spray owing to the compact and less porous morphology. It is concluded that plasma arc sprayed Zn coating is better than arc thermal spray process.

In securing durability of underground structure non-exposed waterproof materials, the company aims to improve durability of waterproof materials by studying more realistic weather conditions than KS standards and developers' durability standards. Analyzing the actual climate data in Korea and the temperature of the basement layer, it is a waterproofing sheet method, a self-adhesive sheet method in which a film and a compound, which are currently widely used as underground water-proofing, and a self-adhesive waterproofing sheet method, etc. We would like to present the guidelines necessary to prevent the temperature situation and waterproof defects that are ideal for setting the endurance conditions later.

Research is underway to incorporate water-repellent agents inside mortars to improve the durability of concrete. Therefore, in this study, the mechanical properties and absorption rate were evaluated by adding a hybrid water repellent in which a liquid and a solid were mixed at a constant ratio.As a result of the experiment, the compressive strength of the mortar added with the hybrid water repellent showed a strength reduction of about 5% than the compressive strength of the OPC, and the overall water absorption was lower than that of the water repellent used alone.

As the construction site has become narrower recently, the importance of mass concrete is naturally being highlighted as skyscrapers become popular. However, it is not possible to install the entire volume per day if the mass concrete is installed due to the Remicon 8⦁5 system and the 52-hour workweek system. When the mass concrete base is divided into several days, cold joints occur because the consolidation of joints is not integrated due to different degree of hardening in the case of the previous layer and the next day. As a result, existing research has shown that if super retarding agent are mixed into Ready Mixed Concrete (hereinafter referred to as Remicon) using sugar as a raw material to delay the curing time of concrete, cold joints are inhibited and cracks are inhibited by reducing the initial hydration heat.

The test method to be developed is to determine whether the waterproof layer applied to the leak-prone part such as cracks and joints has defects such as tearing or lifting of the waterproof layer due to the influence generated from the behavior of the structure under complex deterioration conditions. This is to evaluate the performance of the waterproofing method afterwards. Therefore, by notifying only the pass or fail, the unique mechanical properties of the material or method used are notified to the test client to limit the physical properties of the test body, thereby determining and supplementing the weaknesses of the user material in advance to improve the high quality. We want to prevent damage from water leakage through production and distribution of materials.

This paper introduces the mix design and performance evaluation of Ultra-High Performance Concrete (UHPC). The concrete mixture is designed to achieve a densely compacted cementitious matrix via the modified Andreasen & Andersen particle packing model. The compressive strengths of UHPC designed by this method reached 154MPa. The relationship between packing theory and compressive strength of UHPC is discussed in this paper.

Polymer modified cement mortar (PCM) is commonly used as a repair material. However, in high-temperature environments such as fire, it is more likely to explode than cement mortar. The polymer is thermally decomposed at a high temperature to form a gas, and the gas remaining inside the structure increases the internal pressure to generate a burst. When an spalling occurs, the coating is peeled off and dropped, and high temperature is transmitted to the inside of the structure. In severe cases, even the reinforcing bar is exposed, which can lead to the collapse of the structural member due to severe loss of strength. In this study, in order to reduce spalling of PCM, a fiber mixing method was selected from the refractory method to find an appropriate blending ratio of fibers and polymers.

The objective of the study is to investigate the compressive strength of damaged part by early frost damage and sound part of the concrete placed when exposed to a low temperature of -20℃ for 24 hours in normal concrete. Test results indicated that the compressive strength of damaged part was 14.5 MPa lower than that of sounf part due to early frost damage.

This study is part of the research for improving the performance of mortar and concrete using blended slag aggregate to develope economical and high quality replacement aggregate. The characteristics of the fluidity and strength of mortar using the blended slag, which replaced the blended slag aggregate by 0, 25, 50, 75, 100% for the aggregate volume, were compared and analyzed.

Research for heat insulation of buildings is being carried out, in which a heat exchange barrier is used around the openings and balcony parts as a method for heat exchange blocks. However, the preparation for a fire is inadequate. In order to improve the EPS used as a heat exchange barrier in an attempt to solve this, there is a study on lightweight foamed concrete, but as the amount of EPS used for strengthening fire resistance increases, it becomes lower. There is no strength applied to buildings, and also. There is a limit to the amount of EPS used. In the study, we use oyster shells to secure the EPS replacement rate limit of lightweight Foamed concrete, and try to measure the change of physical properties depending on the unit cement content.

Recently, a method of deriving an efficient 2D floor plan has been attracting attention for remodeling of old buildings with inaccurate 2D floor plans, and thus, studies on reverse engineering of indoor Point Cloud Date(PCD) have been actively conducted. However, in the case of a indoor PCD, due to interference of indoor objects, available equipment is limited to Mobile Laser Scanner(MLS), which causes a efficiency reduction of data processing. Therefore, this study proposes an automatic derivation algorithm for 2D floor plan of indoor PCD based on pixelation. First, the scanned indoor PCD is projected on the XY coordinate plane. Second, a point distribution of each pixel in the projected PCD is derived using a pixelation. Lastly, 2 floor plan derivation based on the algorithm is performed.

The severity of the global climate crisis is increasing due to greenhouse gases caused by human activities. As a result, countries and industries are making efforts to reduce carbon dioxide emissions, the biggest cause of global warming. Many studies have been conducted to predict carbon emissions in the construction sector to reduce this, but they have not actually produced a highly usable formula in the field. Therefore, the two variables 'Curve Fitting' were performed based on the data of excavators and trucks measured at the field. As a result, we have obtained a carbon dioxide emission prediction model for construction equipment, and we would like to use it to help establish an eco-friendly process plan.

In the event of a fire, fire engines usually arrive within 15 minutes and become a fire suppressor. In this paper, an analytical model was established to evaluate the salt damage resistance of concrete according to fire suppression time, and the concentration of salt inside the concrete after fire was measured and the time to reach the critical concentration was assessed by how short.

As buildings in South Korea become more skyscrapers, the risk of fire is also emerging. Thus, regulations, regulations, and guidelines are being improved to prevent the spread of smoke in the event of a fire in high-rise buildings, but research on smoke flow and pressure distribution in vertical spaces is insufficient. Therefore, in this study, the temperature of each floor in the vertical space according to the size of the fire is measured through the miniature model experiment, and the pressure difference is calculated to establish the basic data for the improvement of the performance of domestic air supply facilities in the future. Thus, a scale model of one-sixth the size of the actual building was produced to measure the temperature, and the pressure difference was derived by substituting the value for the expression. The pressure difference varies depending on the size of the cause of the fire, and it is believed that the differential pressure and conditions of the building should be taken into account before calculating the supply volume for the analysis of the pressure difference according to the size of the cause of the fire in the event of fire.

In the design and maintenance of buildings, identifying the degree of damage in the event of a fire is an important factor in fire prevention and fire safety design. In order to predict fire damage, safety measures should be established by predicting the nature of evacuation according to fire, smoke and in-house characteristics, and the effects of the operation of fire safety facilities should also be considered, but in Korea, the risk analysis due to the operation of fire safety facilities is insufficient. Accordingly, this study uses fire statistics and sprinkler inspection data to analyze the degree of fire damage caused by the operation of sprinkler facilities in a probabilistic manner.

Due to the nature of modern society, buildings are becoming larger and more complex. As a result, the design conditions of the building are changing. However, despite the complexities of buildings, the fire resistance performance is still equalized to one hour without considering fire engineering analysis in Korea, so there is a risk according to actual fire design conditions. Therefore, the purpose of this study is to calculate the required fire resistance time for actual fire through fire mechanics analysis and case study.

The masonry structure is constructed by cement mortar binding material of brick objects and uses reinforced hardware (connected hardware or wall tie) together when building. However, over time, the corrosion of reinforced steel and the deterioration of joint mortar as well as bricks cause the risk of collapse. In particular, when the externally decorated brick wall is installed on the concrete girder for each floor, the angle bracket is not constructed or corroded, the full-layer weight load is applied to the wall of 0.5B, which is an example of full-scale or collapse. The purpose of this study is to provide numerical information on the reinforcement design by experimentally studying the structural performance of concrete reinforcement brackets that reinforce the vertical load of the exterior wall.

Recently, a building fire has occurred due to various influences. Accordingly, we are developing an public safety & security unmanned aerial vehicle for fire prevention and initial response to fire. The public safety & security unmanned aerial vehicle is used to grasp the traffic route to enter the fire engine in the event of a fire in a dense structure and to determine the scale of the fire and the area of danger of collapse around the fire site. In this study, an environmental test of the public safety & security unmanned aerial vehicle's heat resistance was performed in an environment simulating a fire scene.

In this study, the characteristics of fine aggregates produced according to the jaw crush crushing gap variation were studied and analyzed in terms of recycled aggregates, and the experiments were conducted in terms of grading, density, water absorption, unit volume weight, grain shape. It was shown that the quality of the fine aggregate was affected by the shape of the morphological crushing.

Recently, as interest in environmental issues increases, minimizing carbon dioxide generated during cement manufacturing is a problem to be solved. In order to solve such a problem, it is required to use an industrial by-product of recycled aggregate, blast furnace slag, and circulating fluidized bed boiler fly ash to replace it on the basis of geopolymer(=cementless). This study examines the characteristics of eco-friendly artificial stone according to the mixing ratio of geopolymer-based recycled aggregate. As a result of the experiment, when the addition rate of the alkali stimulant was 15% and the mixing ratio of the circulating aggregate was 70%, the flexural strength and compressive strength were the highest. Density and water absorption decreased as density of circulating aggregates increased and water absorption increased. However, when the mixing ratio of the circulating aggregate exceeded 70%, the flexural strength and compressive strength decreased. Therefore, in order to obtain strengths meeting the KS standards, the mixing ratio of recycled aggregate was set to 70%, and artificial stone was manufactured using industrial by-products.

In this study, flexural strength and tile adhesion strength were evaluated by using a mortar, dry mortar and an epoxy resin reinforced mortar to examine the adhesion performance by reinforcing the epoxy resin adhesive. As a result, it was clearly confirmed that the effect of improving the adhesion strength by reinforcing the epoxy resin adhesive regardless of the type of tile, and in particular, when applying the epoxy resin adhesive to the porcelain and polishing tiles, it is judged that sufficient adhesion performance can be secured.

This study manufactured the porous foamed concrete granules coated with TiO₂ Nanoparticles, to widen the specific surface area. The Removal rate of concrete granules coated with TiO₂ Nanoparticles was average 56.7%, which was approximately 2.3 time higher than that of the conventional surface TiO₂ coating.

The aim of this study is to evaluate the combination effect of amorphous steel fiber and polypropylene fiber on spalling of the 150MPa level ultra high strength concrete. Considering spalling has a great relationship with water vapor pressure, this paper is focusing on water vapor pressure. The test specimens were heated accordance with ISO-834 Standard Curve using electric heating furnace, the depth of 10mm water vapor pressure formation was tend to get faster and spalling damage become severe when the mixing proportion of amorphous steel fiber increase. When using ultra high strength concrete reinforced with amorphous steel fiber, further research about proper mixing proportion of polypropylene fiber.

In this study, optimum time of drilling for injection of repair material was determined through surface stripping and cracking investigation by drilling from the 1 days to the 3 days of the age for the specimens with ∅100 mm. No surface stripping and cracking occurred on the third day of age, and the compressive strength value was above 14 MPa, which resulted in the appropriate time for drilling on the third day of age.

This study compared and analyzed the fluidity and strength characteristics of mortar using the recycling water, indicates strong alkali properties, as pre-wetting water of artificial light aggregate to increase usage ratio of recycling.

With the rapid progress of industrialization, indoor air quality is a very important factor for modern people who spend most of their day indoors. The recent issue of fine dust and radon on the portal site's popularity search shows that interest in indoor air quality has increased. Fine dust causes respiratory diseases, and radon causes severe lung cancer. The new material was tested using plant activated carbon, palm activated carbon and bamboo activated carbon. Both palm activated carbon and bamboo activated carbon are porous materials and generate smooth physical adsorption. As a result of the experiment, both the activated carbon tends to gradually decrease in strength and fluidity as the replacement ratio increases. The reason for this is that both activated carbons have the property of absorbing moisture, so it is judged that the strength is lowered by absorbing moisture necessary for curing. In the case of fluidity, it is judged that the fluidity is reduced by absorbing the moisture required for the flow. In the future, if the problem of the color of the finished cured body is compensated, it will be possible to manufacture a functional finishing board to replace the existing interior finishing material.

Concrete has a lower thermal conductivity or thermal diffusion coefficient compared to other building materials, so it is widely used as fireproof compartment material or refractory material for structures. However, in the event of thermal damage such as fire, cement curing agents and aggregates act differently, resulting in heat generation or deterioration of tissue due to dehydration, resulting in deterioration of physical properties and fire resistance. Therefore, in this study, the processing structure of cement paste is measured through nitrogen absorption method. The test specimen is a cement paste of 40% W/C and is set at 1000 ℃ under heating temperature conditions. As the temperature rose, the micro-pore mass below was reduced based on about 0.01 감소m, but the air gap above that was increased.Thus, in the range of pores measured in nitrogen adsorption, the air mass tended to decrease under high temperature conditions.

A study was conducted on the production of LEFC using the Precast method, not the on-site construction. LEFC, Light Emotion Friendly Concrete, has the advantage of plastic rods being inserted to allow light to transmit, but because of the lack of adhesion to concrete, it leads to a decline in mechanical performance and durability. Therefore, it is necessary to apply precasting techniques to ensure homogeneous and superior quality of LEFC. In this study, wooden molds were used and plastic rods were arranged on porous acrylic plates. Prototyping was carried out with a UHPC mix proportioning to ensure flowability, self-consolidating performance and mechanical performance.

Recently, the cement industry has been using various wastes as raw materials and fuel for cement as an eco-friendly business. However, most of these waste resources contain large amounts of chloride and alkali, which are concentrated in manufacturing facilities and adversely affect cement production products. Accordingly, in the cement production process, the chlorine ion contained in cement is managed by introducing the Chlorine Bypass System (CBS) into the manufacturing facility and releasing the dust. However, the processing volume of CBS-Dust has been limited due to the shortage of domestic processing companies, and the cost has also been raised, requiring measures to be taken in dealing with CBS-Dust. In this study, rheological properties of CBS-Dust incorporated paste are tested. With the increase of CBS-Dust, flow was decreased due to enhanced viscosity.

In this study, creep deformation characteristics of high strength concrete under dry curing conditions were investigated. It was confirmed that the creep coefficient decreases as the compressive strength of concrete increases. In addition, a modified proposal for calculating the ultimate creep factor of the ACI 209 model can be derived using the measured values.

Currently, the most commonly used EPS insulation material has been mainly used because its ease of adhesion with concrete. However, due to poor adhesion with wallpaper, separate adhesion needs to be strengthened and there are cases of breakage or grooves in the process of dismantling the mold. The biggest problem is that when a fire breaks out, various harmful substances are present and highly flammable. Cork used in this study is a truly eco-friendly building material that is taken from between the outer and inner bark of cork trees and does not damage the wood. Also, it is a porous material that is made up of countless cells and contains an air gap between the cells. It is very light in weight between 0.06 and 0.07 and has excellent insulation with a heat conductivity of 0.04W/mK. In addition, it has high stability in the topic of conversation because it does not produce harmful gas when burned and has self-sustaining properties. However, research on cork, an eco-friendly building material with excellent performance to date, is scarce Therefore, we encourage existing scholars to raise interest in new eco-friendly building materials through this study. It also aims to manufacture insulation boards with new inorganic properties using the low weight and heat conductivity held by the cork.

Recently, concrete expansion anchors which are a type of post-installed mechanical anchors are widely used in reinforcement concrete structures. In order to be used in the reinforced concrete structures designed in accordance with ACI 318-19 or ACI 349-13, the structural performance tests of the concrete expansion anchors should be conducted in accordance with ACI 355.2. The effectiveness factor(k) of concrete expansion anchors should be determined through the reference tests and used for the design of anchorage to concrete according to ACI 318-19 or ACI 349-13. In this study, we will look into the method for determining the effectiveness factor(k) of concrete expansion anchors and anchorage design process of concrete expansion anchors by using the effectiveness factor(k) in accordance with ACI 349-19.

The purpose of this paper is to examine the characteristics of heat and hydration of concrete according to formwork materials. As a result of the experiment, it was found that there were no problems such as concrete heat loss and delay in hydration reaction due to the use of synthetic resin formwork.

Unlike new construction projects, road paving maintenance work shows large productivity discrepancies depending on the conditions of the worksite. The current construction cost calculation scheme, however, only provides daily construction volume categorized by work scope and scale: There are no detailed standards that can be implemented on various types of worksites. To develop standards that enable the calculation of appropriate construction costs by taking into account worksite conditions, the current study conducted on-site surveys and interviews. The on-site research and analysis revealed that location, construction width, the day's worksite lot, work scope, and construction objectives were found to cause differences in construction volume. In addition to the existing work scope and work scape variables, the current study added weight constants reflecting the daily work volume based on movement conditions at site and the size of the worksite lot. In this process, the current study found that even one type of construction project can have fifteen different levels of daily construction volume. Such detailed classification was deemed to enable the proper calculation of construction costs based on worksite conditions.

In order to calculate construction costs properly, it is necessary to add the weight that reflects different worksite conditions. The implementation of the weight, however, is difficult because it is impossible to determine whether wight should be added in basic work or whether weight values are overlapped. Special worksite conditions further complicate the matter. Furthermore, overlapping implementation of weight values result in overestimation of construction costs. The current study clearly analyzed the weight value items in the current construction cost calculation standards, and analyzed the weight value items included under the basic productivity category to propose an improvement of weight standards. Basically, the estimating standards provide 140 weight value items, with different levels of weight given to each item. Among 1,333 items in the estimating standards, 140 include weight values. Some items have two types of weight values.

Flat plate structures are designed in the form of long span due to the development of construction materials and the improvement of construction technology. However, a high-rise structure of a flat plate of 50 less floors is constructed without detailed review of the inequality shortening, long-term deflection of the slab, and cracks. Therefore, it is possible to examine the case of defects in the structure due to deformation and damage of non-structures such as crack and leak, deflection of the door frame, and deformation of equipment ducts. In this study, it is a high-rise structure, and the inequality shortening and long-term deflection of the slab of the flat plate structure were evaluated through finite element analysis, and it was confirmed that prior precision analysis and correction during construction is necessary.

Cracks are caused by drying shrinkage between the upper part of the underground parking lot and the apartment wall. As a result of the investigation, the distance between the apartment and the apartment is more than 45m, and the top slab of the underground parking lot is usually flat when there is not with steps. Therefore, the crack occurs more when the underground parking lot is a PC slab than a RC slab. In this study, the reduction of cracks was conducted by extending the slab, expanding the beam size, increasing the wall thickness, and installing a delay joint on slab. In each case, a finite element analysis was performed to examine the crack reduction method.

When measuring fine dust at a large-scale site such as complex construction, the change in the value of fine dust measurement is large due to the influence of the time, location, wind speed, wind direction, and humidity. This study aims to find out the results of measuring fine dust in an actual construction site and inferring the changes.

The standard for the cost calculation in the field of domestic construction engineering can be largely divided into the construction cost ratio method and the actual cost addition method. However, the standard for calculating the cost of the construction cost ratio method is a trend to switch to the actual cost addition method due to limitations such as not reflecting the characteristics of the construction. Therefore, this study aims to derive implications by investigating and analyzing examples of cost standards in the field of overseas construction engineering, such as the United States, and deriving directions for improvement in domestic cost standards in the future.

In this study, we attempted to present a method for diagnosing the depth of the early frost damage concrete using organic pigments under the cold weather. As a result, it is considered that the organic pigment did not penetrate into the voids of the concrete that had been damaged by the early frost damage and only the surface was adhered. Therefore, when fine particles that can be melted in water and pass through voids are used, it is analyzed that it can penetrate damaged part of the concrete.

Occupational Safety and Health Management Cost, used to protect workers in Korean construction worksites and to create safe working environments, is a legally managed expense item. As this cost item is grounded on the Occupational Safety and Health Act, it is always implemented. However, because there is a ceiling on its rates, insufficient amounts of Safety Management Costs are often allocated to worksites, with the money not being used to areas essential to worker safety. As such, the current study raises the need to develop a set of standards to enable some items under the Occupational Safety and Health Management Costs-appropriated under the rate of indirect costs-to be appropriated as direct construction costs. As a preliminary step in this effort, the current study will provide basic data that can be used to create construction cost calculation standards for items that can be calculated as direct construction costs.

Recently, the need for smart construction technologies related to the Fourth Industrial Revolution has been increasing in order to improve productivity of the construction industry. The Ministry of Land, Infrastructure and Transport has established Smart construction technology road map to commercialize the smart construction, and research and development is also underway. However, due to the lack of cost estimation standards for such smart construction technologies to be deployed to actual sites, smart construction technologies are not actively applied to construction sites. In particular, cost estimation standards are needed for construction machinery equipment with ICT technology that is currently available for commercialization. Therefore, as a preliminary study for the development of smart construction cost estimation standards, a case study was conducted on ICT construction estimation standards in Japan and present them as basic data for standards in Korea.

This study aims to develop the hydration heat reducing material (powder type) to lower the heat of hydration of mass members in the extremely hot weather condition. In this study, we applied the developed material to the concrete that used two kinds of binders with cement and evaluate the concrete properties with it.

The EMP slip rate was compared with the general concrete using the electric arc furnace slag as an aggregate. Experimental results show that the shielding rate of concrete specimens using electric arc furnace slag increases. It is considered that the shielding rate is increased due to the high Fe content in the components of the electric arc furnace slag aggregate.

CO2 emissions are caused by cement manufacturing process. To solve this problem construction industry are using industrial by-products to replace cement. In this study, three different industrial by products were used and mixed with hybrid fibers to enhance bond strength. As the result, Regardless of the mixing rate of silica fume, the compressive strength of the ternary non cent mortar was higher than that of OPC and binary. And mixed hybrid fibers cured by room temperature compressive strength were 23% higher than those without hybrid fibers.

In this study, oxidized graphene nanoplatelet(GO) was prepared by oxidizing graphene nanoplatelet(GNP) with nitric acid in order to solve the problem of dispersion of GNP, one of nano materials. GNP/Epoxy and GO/Epoxy were prepared by mixing GNP, GO with 0.1, 0.3, 0.5 and 1.0 wt.% in epoxy and the mechanical properties, bond performance were evaluated. As a result, GNP/Epoxy and GO/Epoxy showed higher tensile strength than Neat Epoxy at the 0.1, 0.3 wt.%. Especially, when 0.1 wt.% of GO was incorporated into epoxy resin, it showed highest tensile strength. It was confirmed that acid treatment of GNP was effective in improving the mechanical properties of epoxy paint. However, graphene material was found that it was not effective in improving the bond strength of the epoxy paint.

This study evaluated the effect of foam volume ratio on shear friction behavior of bottom ash based lightweight aggregate concrete (LWA_BA). The LWA_BA with different foam volume ratio ranged between 8 and 25 MPa for compressive strength(f_ck), 17.3~62.5 kN for shear capacity at first shear crack(V_cr), 31.1~73.8 kN for shear friction capacity(V_n), and 0.01~0.03 mm for slip at maximum peak load(S₀). f_ck decreased with increase in the foam volume ratio, showing that this trend was also observed in V_cr, V_n, and S₀.

This study In order to reduce the amount of cement that generates a large amount of carbon dioxide and attempts to find a recycling method to solve environmental problems by using biomass fly ash. Experiments were conducted according to replacement ratio of biomass fly ash based on GGBFS, The test items are flowability, air content, unit volume weight, water absorption, flexural strength and compressive strength. As a result of the experiment, as increased replacement ratio of biomass fly ash, the flowability and air content was increased. As increased replacement ratio, the density was decreased and water absorption was increased. The compressive strength tended to decrease as increased replacement ratio. The flexural strength tended to increased as increased replacement ratio.

Recently, some researchers have found, as a part of the development of new materials, the rice straw ash can also be used as a pozzolanic material for concrete considering similar chemical properties of rice straw ash to that of rice husk ash. Therefore, the purpose of this study was to improve compressive strength of concrete adding agriculture by-product. Compressive strength were tested on rice straw ashes at 600℃ to identify improving strength effect.

The importance of indoor air quality management has recently been highlighted due to environmental problems such as indoor air pollution. Among indoor air pollutants, carbon dioxide occurs in cooking, heating, burning, and causes forgetfulness, dementia and amnesia. Radon, which occurs in building materials, soil and ground, is a type 1 carcinogen that causes lung cancer in the body through breathing. These substances can be released from the room through ventilation, but there is a limit to reducing the amount of indoor activity due to reduced ventilation conditions due to increased indoor activity time. However, these substances can be removed from the gas by adsorption. The purpose of this study was to identify the properties of granular active and powdered active white soil and mix them to make cement-based active white soil adsorbent matrix for carbon dioxide, fine dust and radon gas adsorption, and to evaluate indoor air improvements according to the mixing scale. The results of the experiment showed that active carbon dioxide adsorption performance increased for carbon dioxide and radon as the exchange rate increased through physical adsorption. In particular, the higher the replacement rate of the granular active bag, the better adsorption performance was shown.

The purpose of this study is to measure the electrical conductivity of cementitious composites as an early step to obtain shielding performance by mixing various type of steel fiber into cementitious composites, the main building material of protection facility, to shield electromagnetic pulse (EMP) damage. Fiber such as conductors as amorphous metallic fiber, hooked steel fiber, and smooth steel fiber are mixed into cementitious composites to give electrical conductivity and measure the impedance of concrete using LCR meter. By doing this, the electrical conductivity of each type of steel fiber reinforced cementitious composites (FRCC) is compared.

Recently, as the use of high-performance concrete has become common, various problems related to high-performance concrete have become an issue. Among them, self-shrinkage of cement paste due to low water cement ratio is known to cause problems in the volume stability of concrete. To improve this, studies related to the mixing technology of cement-based materials and nano materials have been actively conducted. Looking at the results of prior research related to nano material mixing technology, generally, research results have been reported in which nano materials are incorporated into cement-based materials to improve material properties1). Among them, it was shown that the mechanical performance and various types of functionality of the cement composite are expressed. Among nano materials, carbon nanotubes (hereinafter referred to as CNTs) and graphenes are used in a mixture with cement-based materials. Accordingly, this study intends to compare the mechanical properties by incorporating various CNTs and graphene into cement paste.

This study evaluated the mechanical properties and alkali silica reaction of mortar according to the mixing ratio of waste glass. As a result, as the mixing ratio of the waste glass increased, the compressive and flexible strength of the mortar decreased due to the slip of aggregate, and the alkali-silica reaction(ASR) increased. So, it is considered that research is needed to prevent slip and ASR of the waste glass aggregate in order to use the waste glass as a fine aggregate for concrete.

A study was conducted on UHPC production using the silicone mold method. UHPC (Ultra-High-Performance Concrete) has the advantage of being able to shape the product in a free-form shape on concrete, but when mass-producing products in one design, such as electronic products, rather than one-time products such as buildings and decorations Demolition is difficult with wood and mold. This study uses silicone molds, UHPC mix to ensure fluidity, self-integrating performance and mechanical performance Prototyping was done proportionally.

In this study, the effect of porous powders on the dispersibility and strength properties of CNTs was examined.As a result of the experiment, it was found that in the case of incorporation of CNT, the compressive strength property was significantly improved by improving the dispersibility of CNT.

Unlike price calculation by cost accounting, which categorizes costs into material costs, labor costs, and miscellaneous expenses to determine the construction budget price, construction cost calculation based on Construction Standard Unit Prices utilizes unit prices extracted from market prices of items from projects already completed to estimate costs of similar construction projects. Although unit price information is collected through construction site surveys to revise these construction standard unit prices every year, but due to the limitations of the site survey method, it is difficult to quickly implement the rapid changes in the construction methods and market prices. As such, an important issue that arose was the identification of work items whose prices need urgent revision. This study conducted research on factors that need to be considered when developing online survey system for monitoring construction site market prices. This study is expected to enhance convenience for users, and provide an efficient data collection and management system for administrators.

Construction Standard Unit Price is the unit price calculated based on the market price for work items in construction projects that have already been conducted. It is used as basic data for calculating the budget price of public construction projects. In the Construction Standard Unit Price Book implemented in the second half of 2020, there are 1,810 types of unit prices. Since 2017, 100-150 construction standard unit prices have been revised semiannually (on January 1 and July 1 of each year) through Construction Site Surveys. Other work items have been set based on the rate of inflation during the corresponding period. Later in 2020, this procedure was changed, with on-site survey period extended to one year to strengthen the construction standard unit price investigation. The revisions previous announced during the second half of the year were changed only to reflect the price inflation rates. With such changes in the revisions to construction standard unit prices, one important issue that was raised: The timing of announcing the revisions during the second half of the year (reflecting the price inflation rates). The market unit wage, which is the unit price standard of labor cost that takes up a large part of the construction cost, is announced in January and September. The figures announced in September is reflected on the construction standard unit price four months later in January, but the market unit wage announced in January is reflected only six months after in July, which causes a timing issue. As such, the current study analyzed problems rising from the changed timing of the announcements of the construction standard unit price during the second half of the year, in addition to analyzing their impact on public construction projects.

Accurate estimation of concrete strength development at early ages is a critical factor to secure structural stability as well as to speed up the construction process. The temperature generated from the heat of hydration is considered as a key parameter in predicting the early age strength. Conventionally, concrete temperature has been measured by temperature sensors installed inside concrete. However, considering the measurement on building structures with multiple floors, this method requires reinstallation and repositioning of hardware such as sensors, data loggers and routers for data transfer. This makes the temperature monitoring work cumbersome and inefficient. Concrete temperature monitoring by using thermal remote sensing can be an effective alternative to supplement those shortcomings. In this study, image processing was carried out through K-means clustering technique, which is a unsupervised learning method, and the classification results were analyzed accordingly. In the future, research will be conducted on how to automatically recognize concrete among various objects by using deep learning techniques.

There is no disagreement that the construction sector will play an important role in inter-Korean economic development cooperation. However, very few studies have been made at North Korea's construction technology. North Korea shows a lot of differences from South Korea, from the quality standards of building materials to construction technology. It is clear that these differences will be a stumbling block to the promotion of construction projects in the inter-Korean cooperation stage. Therefore, the start of inter-Korean economic development cooperation should be preceded by work to clearly recognize each other's differences and lay the foundation for integration or compatibility. The purpose of this study is to compare the construction technology of rebar concrete construction. We compared the differences with Korea's construction method based on the construction books recently published in North Korea, and derived the characteristics of North and South Korea for each detailed process of reinforced concrete construction.

In this study, a questionnaire survey on the occurrence status of fine dust in urban construction sites and the response level was conducted. Based on the results of the survey, it is intended to be used as basic data for establishing a method to reduce fine dust in construction sites.

In this study, the market growth potential for the construction sector and the company's ease of entry were analyzed by using construction scale and risk data among global insight data. The survey was conducted in 74 countries. The purpose is to provide basic data whose result can be used as policy-based data for the overseas construction industry.

The 3D scanning technology is being introduced for quality inspection of building construction. Therefore, this study tried to confirm whether it is possible to check the quality of rebar by using 3D scanning. After rebar placed on the formwork slab was scanned with a 3D scanner, the rebar spacing was confirmed by overlapping with the CAD drawing. As a result, the 3D scanner was able to check the quality of rebar work on one floor at a time. Therefore, 3D scanning could be used for quality inspection of rebar works such as columns, beam and girders, walls, and slabs in the future.

As the fire inside the building grows rapidly, ejected flame from an opening occurs due to flashover. As a result, the number of cases where the flame spreads to the exterior of the building and rapidly expands to the upper floor is increasing. In particular, in the case of the fire in the Daebong Green Apartment, Uijeongbu in 2015, it was a case where the flame spread to adjacent buildings due to the opening eruption flame from the first ignited building, causing great damage to three apartments. Therefore, this study is to introduce an international standard under development that estimates the shape and properties of the ejected flame from an opening and quantitatively evaluates the radiant heat flux received by the exterior wall of the building by assuming the occurrence of the ejected flame from an opening.

The risk of a fire in a building is closely related to the usage of the building. In particular, all fires that occur in a building are not risky to safety of human life, and it is associated with the combustion area and the increase of total floor area of the building. Therefore, this study focused on safety of human life in terms of the statistics of fire with considering the aspect of growing fires and analyzed the statistical data of fire for 10 years. As for the analysis on fire, the time of occurrence by usages of buildings, frequency of occurrence and the ratio of casualties etc. were analyzed. It is expected that results of this study could be used for evaluations on a variety of parts in terms of design, construction and maintenance of buildings.

Strarting with Buyeong Apartment in Dongtan-2 disrict in 2017, collective complaints of residents are frequently occurring due to low quality problem such as improper construction and defects of apartment houses. Because of this, the Ministry of Land and Transport is preparing a comprehensive improvement scheme to improve the quality of Apartment Housing(AH), taking into account the continuing complaints from the residents of AH and the problem raised by the National Assembly. The basic profile of the improvement scheme is induce the tenants and experts to discover and point out defects that are repaired until the date of use inspection or due date. For this purpose, we suggested this defects management system linkaged by the preliminary inspection and quality inspection system for prospective occupants. In this context, this paper aims to suggest an effective likage method between the preliminary inspection of prospective residents and the quality inspection system implemented by local governments as an ordinance.

Recently, as the era of economic cooperation on the Korean Peninsula approaches, the role of the building sector, such as humanitarian reorganization of North Korean housing, is increasing. The purpose of this study is to find out the current location of North Korean housing standards through the North Korean Housing Survey. For the survey, a survey was conducted through 79 North Korean defectors. The main construction methods of North Korean housing are reinforced concrete, steel framed, wooden framed, masonry, and reinforced concrete walled and prefabricated. The residential environment satisfaction items consist of durability, waterproof, heating, ventilation, heat insulation, air tightness, mining, soundproofing, disaster safety, fire safety, and crime prevention. The result is as follows. The housing construction method in North Korea, which lived at that time, consisted of 21 people (30.88%) of reinforced concrete frames, 18 people (26.47%) of wooden frames, 17 people (25%) of masonry walls, 5 people of prefabricated structures (7.35%), and reinforced concrete. Two people (2.94%) were walled. Among these, the wooden frame type had the lowest satisfaction level for each item, and the reinforced concrete had a high level of dissatisfaction in the items of heating, confidentiality, and disaster safety, and the other item had a high level of satisfaction. The masonry wall type has a relatively high satisfaction level in terms of insulation, confidentiality, mining, and disaster safety.

The construction industry is a workforce dependent industry. However, problems with wages have occurred frequently from the past to the present, and the number of skilled workers is decreasing due to the influx of new skilled workers and the departure of existing skilled workers. In response, this paper surveyed the actual status of wage calculation and analyzed the problems and presented a rough improvement plan by surveying the functional personnel of domestic frameworks.