Pipe support is a representative structure that supports slab formwork, and it is a representative temporary equipment that has been systematically managed since the 1990s when the domestic temporary equipment performance test system was introduced. Nevertheless, it is also a reality that many of the products in circulation are used products that are reused and do not meet the performance of the initial manufacturing stage. However, if only new products are insisted, it could lead to delays in the process due to an increase in construction costs and difficulties in timely delivery. On the contrary, it is not acceptable for the safety of the construction site to use products of low quality without verification procedures or standards. Therefore, this study attempts to grasp the management system such as safety certification for temporary equipment and the actual condition of quality control to maintain performance, and propose improvement plans.

The unit-water content of concrete is one of the important factors in determining the quality of concrete and is directly related to the durability of the construction structure, and the current method of measuring the unit-water content of concrete is applied by the Air Meta Act and the Electrostatic Capacity Act. However, there are complex and time-consuming problems with measurement methods. Therefore, high frequency moisture sensor was used for quick and high measurement, and unit-water content of mortar was evaluated through machine running and deep running based on measurement big data.

While non-uniform shapes are appearing as an apparent building style recently, most architects predominantly think structure and construction technology should support the designed shape of non-uniform structures determined by the architect. Within such a governance structure of architect's perception, the role of an engineer is emphasized for technical support only. Especially, in making a decision on a structural design and plan, if various and objective reviews are not conducted, the design is very likely to be left only as a drawing even if the design is appropriate for criteria and norms. With the recognition of such problems, the present study attempted to propose an equal cooperative relationship between architects and engineers in designing non-uniform structures in the future.

This research is part of the research for unifying the mass concrete and utilizing the rate of super retarding agent. We analyzed the performance of super retarding agent under low temperature conditions. It was found that there was no deterioration in fluidity and air quality due to the change in the super retarding agent mixing rate. It was found that when super retarding agent was mixed up to 0.5 %, it was delayed for 22.3 hours at 20℃, 48.2 hours at 10℃, and 48.5 hours at 5℃. Therefore in order to ensure the performance required at the site, the super retarding agent mixing rate must be determined by fully considering the situation at the site. In addition it will be analyzed that super retarding agent performance analysis at high temperature will be required in subsequent studies.

Free-form buildings usually have large curved shapes on the outside. In order to construct this curved shape, the exterior of the building must be divided into easy-to-manufacture shapes, and the segmented panel is called the FCP(Free-form Concrete Panel). These FCPs have different shapes and cannot reuse molds. To solve these problems, the researchers developed FCP manufacturing equipment to manufacture a mould of FCP. However, the developed equipment alone cannot completely manufacture FCP's mould. This is because there is no mould to implement side of FCP. Therefore, it is necessary to develop a side form of FCP that can be applied to FCP manufacturing equipment. To this end, this study analyzes the basic requirements that side mould should have before developing side mould.

The circumstances of overseas construction market is developing into quite complicated and diversified trends. Construction circumstance is escaping from localization to the open competitions, and from developing countries focused to the resources developing countries. Thus, new strategies for order competitiveness improvement based on our know-hows are required to secure the order volumes. This study has analyzed domestic construction companies' order trends in overseas construction market, and proposed strategic plans through analyzing of Order Causes on overseas construction projects to improve the order competitiveness.

The Temporary construction refers to the construction or dismantling of temporary structures installed for the construction of the main structure at the construction site, and the members constituting this temporary facility are called temporary equipment. Temporary equipment used in construction sites is mostly used products that are reused rather than new products, and it is necessary to consider performance degradation due to repeated use. This study is a preliminary study to develop the performance evaluation criteria applied to temporary equipment that is distributed and reused for secondhand. This study is to analyze the performance status of temporary equipment of used goods owned by rental companies by condition grade through performance tests.

The ElectroMagnetic Pulse (EMP) destroys social infrastructure at once and causes social chaos. However, currently major infrastructures are constructed of concrete that does not have electromagnetic shielding performance. In this study, using the arc metal spraying method is used to evaluate the shielding performance and construction performance of concrete. The electro-magnetic shielding effect is measured by fabricating a shielding room with reference to MIL-STD-188-125, and the construction performance is evaluated by measuring the adhesion strength of thin metal sprayed film-concrete. As a result of the study, when the metal spraying method is applied, the shielding effect is higher than that of the special electro-magnetic shielding concrete, and it is considered to be more economical than the existing metal plate (3~5 mm).

This study is about high strength self-leveling mortar according to the mixing ratio of polymer. The self-leveling mortar currently released in Korea maintains a compressive strength of 40 Mpa as of 28 days. In addition, the level of bonding strength and flexural strength are kept the same. However, through this study, it is confirmed how the self-leveling mortar with a compressive strength of 60Mpa as of the 28th is shown according to the amount of polymer mixed. Experimental factors were configured according to the amount of polymer mixed, and the types of experiments were to confirm compressive strength, flexural strength, adhesion strength and flow. In addition, by confirming the early strength, a study was conducted to improve the quick workability compared to the self-horizontal mortar in the market.

In this study, effect of surface modification of waste glass for fine aggregates on the mechanical properties and alkali silica reaction of mortar was analyzed. As a result, it was confirmed that the incorporation of waste glass fine aggregate decreases the mechanical properties of the mortar and increase the alkali silica reaction expansion. On the other hand, the surface modification of the waste glass fine aggregate is effective in improving this problem. However, unlike green and brown waste glass, it is judged that an additional experiment to determine the cause is necessary for white waste glass where alkali silica reactive expansion occurs extremely.

During the molding process of the existing interlocking block, the pigment is firstly laid, and cement is poured on the pigment secondly to give vibration. Interlocking blocks made of conventional cement are entirely dark where the pigment area is removed. On the other hand, when looking at the mortar with oyster shells added, the color is closer to that of the existing cement mortar. Therefore, if an interlocking block is produced by adding a pigment to a mortar with an oyster shell added, it is considered that the amount of pigment is less than that of the existing interlocking block. This study is a basic study of interlocking blocks. To investigate the strength characteristics of mortar using oyster shell powder as aggregate, W/C is 25%, 50%, oyster shell replacement rate is 0%, 25%, 50%, 75%, 100% was substituted to make a mortar and its strength change was studied.

In this paper, we investigated the performance of synthetic graphene oxide-functionalized carbon nanotubes (GF) to promote cement hydration and increase the mechanical properties of cement paste. The enhancement effect of GF on the various properties of cement paste was evaluated via the mechanical strength, X-ray diffraction, and heat of hydration of cement paste. The results clearly showed that GF incorporation into cement paste promotes the early hydration of cement paste, generates more hydration products, which results in the mechanical improvement of cement paste. The compressive and splitting tensile strength were increased by 32.17% and 17.31%, respectively, compared to ordinary Portland cement at 28 days of hydration.

In this study, as part of the foundation for advancing the material compounding aspect to reduce hydration heat cracks in the mat foundation on which the mass concrete is constructed, the degree of concrete varieties of cement is used. The setting time was measured and comparative analysis was performed. Results It was confirmed that the concrete using LHC was more effective than the concrete using OPC in reducing the use of SP, the calorific value of the concrete was low, and it was more effective in preventing cracks. It is also terminated after 10 hours and it is determined that the use of LHC can reduce the cracks caused by the heat of hydration of the mat foundation.

This study measured the mechanical performance and residual strength of high strength/normal strength mortar mixed with waste glass fine aggregate after alkali-silica reaction and alkali-silica reaction. As a result, the effect of improving the slip phenomenon of the waste glass fine aggregate in the high-strength mortar was not significant, but rather the amount of ASR was increased.

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. The compressive strength of 𝛾-C₂S added GGBFS cement mortar is higher compared to without 𝛾-C₂S in accelerated carbonation (AC) up to 14 days of curing but once the curing duration is increased, there is no significant improvement in compressive strength. This study suggests that 𝛾-C₂S can capture the atmospheric CO₂ (mostly generated from cement and metallurgy industries) and utilized in construction.

In recent years, prices have risen sharply, and housing has become an object of investment. Accordingly, the expansion of the supply of public rental housing with publicity and the conversion of pre-sale are emerging as an alternative to stabilize the housing market. However, the method of calculating the pre-sale price applied for each rental period has a problem that there is a large difference from the construction cost at the time of construction As an improvement measure, there is a method of applying a conversion price for 5-year public rental housing and the price control. Each has its strengths and weaknesses, and we apply the most appropriate improvement measures in consideration of present and future values.

Since a lot of fugitive dust is generated at construction and civil engineering construction sites in Korea, the fine dust regulation at construction sites has been strengthened in accordance with the implementation of the Special Act on Fine Dust Reduction. In a construction site, water is generally sprayed to temporarily reduce the generation rate of scattered dust, but there is a problem that when water evaporates, it scatters again. In this study, the performance of a scattering dust inhibitor incorporating a polymer that stabilizes the ground and reduces the rate of scattering dust by forming a polymer film even when water evaporates using a polymer and a surfactant was evaluated.

This study has resulted in the following findings. First, Using more than 30% of GBFS to replace FA enabled bleeding control through improved fluidity. Moreover, it has been confirmed that effective strength and proper quality can be achieved when it was applied as a backfilling material with higher early strength than the base material. Second, When using more than 30% of FNS to replace sand, it was found that adding 0.3~0.35 of the AE agent is effective for bleeding control through improved fluidity. Third, When using more than 30% of both GBFS and FNS in combination, it was found that adding 0.3~0.35 of the AE agent is effective for bleeding control through improved fluidity. Also, it was confirmed that proper mixing of 15~60% of GF secured the effective strength and desired quality as a refiller and joint filler material.

Lauric acid (LA) which is also known as dodecanoic acid has been selected as the phase change material (PCM) owing to eco-friendly in nature. A systematic study has been conducted for encapsulation of LA (core) with silicon dioxide (SiO2) as shell material. Different core-shell ratio was chosen to microencapsulate the LA with 10 ml of tetraethyl orthosilicate (TEOS) as the precursor solution for the formation of SiO2. The synthesis of microencapsulated LA was carried out at 2.5 pH of precursor solution. The synthesized microencapsulated LA are characterized by Fourier transform infrared spectroscope (FT-IR) and X-Ray Diffraction (XRD) which confirmed the presence of SiO2 shell on the surface of LA.

The purpose of this study was to contemplate the effectual waterproofing materials and construction methods for the restoration of underground infrastructures using precast arches(PC-Arch). Until now, there were no proper waterproofing guidelines for waterproofing precast arch tunnel when restoring cultural heritage or building underground infrastructures for noise control. Asphalt membrane sheets were commonly used, but the efficacy of waterproofing done on the precast segment was vulnerable. This study aims to examine the Synthetic Rubber Polymerised Gel(SRPG) proposed in ISO TR 16475, a guideline for the repair of water-leakages, and to demonstrate field applicability based on the waterproofing solution used on the road improvement project in front of Changgyeonggung Palace in Yulgok-ro, Seoul, Republic of Korea.

Oyster shells and egg shells consist of CaCO3, which is known to have excellent fire performance as the main component, and research is currently being conducted as a fireproof board material. Therefore, in this study, the physical and chemical properties of oyster shell powder and egg shell powder are studied to find out the applicability of fireproof board

Recently, as people's interest in environmental pollution increases, interest in indoor air pollution as well as outdoors is increasing. Accordingly, this study prepares functional paints by mixing powder activated carbon, which is a porous material, into aqueous paints, and examines the adsorption performance of volatile organic compounds (VOCs) and formaldehyde (HCHO). As a result of the experiment, the concentration of volatile organic compounds (VOCs) and formaldehyde (HCHO) tended to decrease as powder activated carbon was incorporated. It is believed that physical adsorption was achieved by the micropores of powdered activated carbon. However, in the adsorption test method, it is judged that the concentration was affected by the inflow of outside air as the chamber cover was opened to put the test object in the empty chamber where a certain concentration was maintained.

Recently, various maintenance materials and construction methods have been developed to secure the sustainable performance of structures. However, waterproofing of underground structures where groundwater infiltration is present is very difficult. In particular, the location of underground structures such as subways is very deep, and it is difficult to apply waterproof materials and construction methods in the case of structures accompanied by vibration. Therefore, we intend to study materials and methods for waterproofing leakage resistance in special environments such as underground structures.

The thermal spray coating process is being used to protect the metals and alloys from wear, abrasion, fatigue, tribology, and corrosion failure. Therefore, in the present study, Al and Zn was deposited by plasma arc thermal spray process onto the steel substrate and their performance was assessed. The bond adhesion result shows that Al coating has higher value attributed to compact, dense, and less porous compared to Zn coating which contain defects/pores and uneven morphology assessed by scanning electron microscopy (SEM). Electrochemical results show that the Al coating exhibited higher impedance value compared to Zn in artificial ocean water solution at prolonged exposure periods. However, both coatings show the increment in polarization resistance with exposure periods which reveal that porosity of coatings is filled by the corrosion products.

The construction industry has the highest occupational fatality and injury rates related to accidents of any industry. Accordingly, safety managers closely monitor to prevent accidents in real-time by installing surveillance cameras at construction sites. However, due to human cognitive ability limitations, it is impossible to monitor many videos simultaneously, and the fatigue of the person monitoring surveillance cameras is also very high. Thus, to help safety managers monitor work and reduce the occupational accident rate, a study on object recognition in construction sites was conducted through surveillance cameras. In this study, we applied to the instance segmentation to identify the classification and location of objects and extract the size and shape of objects in construction sites. This research considers ways in which deep learning-based computer vision technology can be applied to safety management on a construction site.

Recently, government office buildings have become important in reducing maintenance costs. However, the loss of information raised a problem for maintenance work that could not meet the needs of users. Therefore, this study proposed a BIM-based integrated maintenance system for public offices in Jeju to efficiently maintenance work. The system can be integrated with IoT sensors, big data and artificial intelligence technologies to integrate information that occurs throughout the building's entire life cycle to exchange information. This system is also scalable to buildings, plants, region and urban infrastructure facilities as well as single buildings. It is expected that the system will provide reliable, high-quality, real-time information for efficient maintenance work, thereby supporting decision making and appropriate budget planning.

Large fires continue to spread throughout the building, including the fire in Uijeongbu in 2015, the fire in Jecheon in 2017, and the fire in Miryang in 2018. According to the above fire case investigation, major problems were the fire resistance performance of compartment members such as fire doors, the fire spread due to damage to exterior wall openings, and smoke spread through vertical openings. However, in South Korea, only specification design is implemented for buildings that are not subject to performance design. In addition, the analysis of the fire resistance performance standards of building members in the specification design showed that fire doors were not specified in detail for 60 minutes of insulation performance and 60 minutes of fire resistance performance of E/V doors, limiting the prevention of fire spread. Therefore, the purpose of this research is to prepare measures to prevent the spread of fire by presenting simple transplants for calculating the required fire time according to the architectural design conditions for the performance design of the components of the fire room according to the purpose of use of the front of the building.

After the fire in Grenfell, a special fire safety survey was conducted, and the spirit of building fire safety is increasing. However, as can be seen from the fact that more than 80 people were injured in the Ulsan residential fire in 2020, there are no cases of making it a life safety standard for buildings, and there is an urgent need to investigate this. In this research, we will investigate the five fires that occurred in Grenfell, England, derive the problems, and use them as basic data for establishing the safety standards for Korean-style human life in the future.

The purpose of this study is to find out how construction sites workers experience adaptation processes in relation to the prevention of safety accidents in the workplace through the method of grounded theory. In order to understand the experience of preventing safety accidents of workers at construction sites, a grounded theory analysis method was chosen. In order to achieve the purpose of this study, the first questionnaire was sent to 17 people working in the construction site by e-mail, and the participants of the study were met one by one for in-depth interviews. As a result of this study, the paradigm model of the experience of preventing safety accidents of workers at construction sites was classified into causal conditions, contextual conditions, central phenomena, intervening conditions, action/interactions, and outcomes. The conclusions of this study are as follows. First, forming a safety culture that can improve the safety awareness of construction sites is a priority. Second, it is necessary to improve self-management capabilities so that construction workers can accurately diagnose their current state such as their own body, emotion, and cognition and provide appropriate safety education. Third, providing safety education for construction workers with negative thoughts or distorted beliefs about safety accidents needs to include psychological treatment and counseling, such as methods of emotional purification, methods of relieving and managing stress, and methods of removing trauma.

When evacuation safety Design of buildings, the calculation of evacuation capacity is the most important factor that it directly impact of evacuation safety performance. However domestic standards is not consider about occupant characteristics. also the case of domestic, it has the problem that the law is partially applied when the fire safety design of buildings. Therefore, in this study we anlayze the evacuation capacity standards of each countries as basic study for development the Korean Life Safety Standards

Real-time information on the construction project required by the owner make the project's transparency and overall productivity will be improved. This study analyzes domestic and foreign patents for construction project management to identify trends in technology development, construct cloud-based construction project management system solution UI, and proposes functions and services for each module. Trend research is conducted through patent search, and the analysis is divided into quantitative analysis which means quantitative statistics and qualitative analysis which means the technical contents of each patent. The construction project management system solution is based on smart devices at small and medium-sized sites, allowing both the owner and the construction personnel to share information.

Accidents in the construction industry are very high compared to other industries, and the number is also increasing steeply every year. Relevant studies were limited for solving the problems. The purpose of this study is to develop a comprehensive risk prediction process for personnel deployed at construction sites on safety management. First of all, the variables were divided into fixed, real-time and working types variables, and the relevant comprehensive data were collected. Second, the probability of a disaster was derived based on the collected data, and weights for each variable were calculated using the dummy regression analysis method using statistical methodology. Lastly, the resulting weighting and disaster probability equation was constructed, and The Final Risk Calculation Formula was developed. The Final Risk Calculation Formula presented in this study is expected to have a significant impact on the establishment of effective safety management measures to prevent possible safety accidents at construction sites

Predicting the compressive strength of concrete is important for shortening construction time and reducing construction costs. In this study, the coefficients required for maturity method and compressive strength prediction equation were calculated by measuring the cement hydration reaction rate, concrete setting time and ultimate strength. The experiment was conducted in an isothermal environment of 10℃, 20℃ and 30℃ using a normal Portland cement, and the experiment was conducted with a total of 9 levels of W/C (40%, 50%, 60%) of 3 levels for each temperature. As a result of comparing the predicted strength and the measured strength for each blend, only an error of less than 5% was found for all blending and curing periods.

In this study, in order to check whether the adhesion strength can be secured when installing concrete by mixing super-retarding agents, the splitting tensile strength of the joints of each mold was measured and then analyzed. The results of the experiment showed that the bonding performance of the joint is adversely affected if the installation delay is delayed for more than 24 hours, and that the attachment performance can be secured if the installation is delayed within about 24 hours.

An alkaline activator was synthesized by dissolving waste glass powder (WGP) in NaOH-4M solution to explore its effects on the Class-C fly ash (FA) and ground granulated blast furnace slag (GGBS) based alkali-activated material (AAM). The compressive strength and porosity were measured, and (SEM-EDX) were used to study the hydration mechanism and microstructure. Results indicated that the composition of alkali solutions was significant in enhancing the properties of the obtained AAM. As the amount of dissolved WGP increased in alkaline solution, the silicon concentration increased, causing the accelerated reactivity of FA/GGBS to develop Ca-based hydrate gel as the main reaction product in the system, thereby increasing the strength. Further increase in WGP dissolution led to strength loss, which were believed to be due to the excessive water demand of FA/GGBS composites to achieve optimum mixing consistency. Increasing the GGBS proportion in a composite also appeared to improve the strength which contributed to develop C-S-H-type hydration.

This study compared and analyzed the flow and strength characteristics of cement paste according to the rate of mixing of amorphous metallic fiber as part of the research for the development of amorphous metallic fiber reinforced cement composite.

Cement paste is the basic material constituting concrete and the most basic data of workability. This study quantitatively evaluated the measured data using a ring flow and a rotary viscometer to estimate the flow of cement paste, and also evaluated the flow and rheology over time. For this, the current work has studied admixtures that affect the fluidity of cement paste. As a result of the experiment, since fluidity and plastic viscosity are inversely proportional to each other, more experimental studies are needed to obtain high fluidity and high viscosity at the same time.

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. Therefore, in this research, the proper use of VMA was suggested to prevent segregation.

With the increasing importance of environmental issues, the cementitious materials with self-cleaning or photocatalytic properties by introducing TiO₂ materials have been gaining a lot of attention. In this work, the influence of TiO₂ particle size and structure on its photocatalytic effect in cement paste was investigated. The degradation of methylene blue solution was used as the parameter for evaluating the photocatalytic effect of micro-TiO2 (m-TiO₂), nano-TiO2 (n-TiO₂), and TiO₂ nanotube (TNT). Moreover, the effect of these three TiO₂ materials on the cement hydration products was characterized by X-ray diffraction (XRD) and thermgravimetric analysis (TG). According to the results, it can be found that all of the TiO₂ materials promoted the formation of hydration products, especially TNT. On the other hand, the m-TiO₂ exhibited a better photocatalytic effect compared to other materials.

The purpose of this study is to explore the possibility of estimating optimum surface finish time of the fresh concrete placed at the job site by applying a surface hardness test meter(Durometer). Tests are carried out by measuring and comparing the Penetration resistance test and hardness test by Durometer. Penetration resistance tester and improved Durometer are similar, but the higher the temperature, the higher the setting time, and the higher the correlation was shown. When the hardness value of the improved Durometer is about 50 HD, it is found that the initial and 80 HD represent the end. It is expected that this will be useful in determining the finish time of the surface at the actual site.

Utilization of upgraded fine fly ash in cement-based materials has been proved by many researchers as an effective method to improve compressive strength of cement based materials at early ages. The addition of fine fly ash has introduced dilution effect, enhanced pozzolanic reaction effect, nucleation effect and physical filling effect into cement-fly ash system. In this study, an integrated reaction model is adpoted to quantify the contributions from cement hydration and pozzolanic reaction to compressive strength. A modified model related to the physical filling effect is utilized to calculate the compressive strength increment considering the gradual dissolution of fly ash particles. Via combination of these two parts, a numerical model has been proposed to predict the compressive strength development of fine fly ash mortar considering fly ash fineness. The reliability of the model is validated through good agreement with the experimental results from previous articles.

In this study, the analysis was conducted in the aspect of non-hardened concrete of Ternary Mixed Aggregates, and it was determined that flowing and amount of air increased as the mixing combinations of RS increased. However, it is difficult to see the phenomenon only as a result of increasing mixing combinations of RS, and it is thought that the influence of CS and SS also plays a large role. For later analysis, we plan to conduct research on compressive strength and shrinkage according to age, and analyze more suitable mixing combinations.

Oyster shells are characterized by coarse and coarse grains, but similar in strength to sand, and egg shells are fine grains but weak in strength. In terms of supply and demand of raw materials, oyster shells can be supplied only in limited periods and regions in winter and south coast of the year, but egg shells have the advantage of being able to supply and supply nationwide 365 days. This study aims to study the change in strength characteristics by mixing oyster shell powder and egg shell powder with the same particle size and mixing up to 150%. The conclusions of the flexural and compressive strength tests of mortar mixed with oyster shell powder and egg shell powder are as follows. The 7-day flexural and compressive strength with ESP added and the 3-day flexural and compressive strength with OSP added were similar, which is thought to be because the strength of OSP is higher than that of ESP.

In this study, the compressive strength and porosity characteristics of cement mortar mixed with liquid and powder composite water repellent were evaluated. When the liquid water repellent was mixed, the compressive strength at 28 days of age was 42% compared to OPC, and the compressive strength was greatly reduced. However, the 28-day compressive strength of the powder water repellent mixture and P5L1, P6L1 liquid and powder composite water repellent was about 97% compared to OPC, and there was little decrease in compressive strength.

This study is aim to assess mechanical properties which is highly related to structural safe and durability of 100MPa high strength concrete mixed with amorphous metallic fiber. All specimens were heated with low velocity heating rate(1℃/min.), residual compressive strength and residual flexural strength was evaluated. The specimens were cooled down to room temperature after heating. As a result, in the case of 100MPa high-strength concrete, the residual compressive strength enhancing effect of amorphous metallic fiber has showed with the mix proportion of fiber. In addition, residual flexural strength showed more regular pattern before 300℃ then residual compressive strength, but simillar decreasing behavior was shown after 300℃ like residual compressive strength. Further study about fiber pull-out behavior and fiber mechanical, chemical property change due to temperature is needed.

In this study, the temperature history and compressive strength of the concretes according to the type of cement were measured and analyzed in comparison as part of the experiment on the material mixing side to reduce the hydration heat crack of the mat foundation constructed with mass concrete. As a result, the peak temperature and maximum temperature reach time of concrete using high rapid cement were shown to be similar to that of semi rapid cement. In particular, in compressive strength after three days, semi rapid cement was measured higher than that of concrete using high rapid cement. Therefore, if semi rapid cement is used in accordance with the site conditions, it is deemed possible to shorten the air due to reduction of temperature cracks and improvement of initial strength.

In this study, the effect of the change in the cement contents on the basic properties of the concrete and the estimation of the cement contents of hardened concretes using the hydrochloric acid melting heat. As a result of the study, as the cement contents increased, the fluidity and compressive strength increased, and there was no significant difference in the air contents and the unit volume mass. In addition, it showed a high correlation when compared with the estimated cement contents derived using the hydrochloric acid melting and the cement contents at the time of mixing. Therefore, it is considered that the hydrochloric acid melting is possible as a method of estimating the cement contents of concrete.

Red mud is a highly alkaline waste by-product of the aluminum industry. Although recycling of red mud is being actively researched, a feasible technological solution has not been found yet. In this study, we propose that neutralization of red mud alkalinity could assist in its use as a construction material. Neutralized red mud ( pH 6-8) was prepared by adding sulfuric acid to liquefied red mud (pH 10-12). After adding liquid and neutralized red mud to the cement paste, the heat of hydration was measured. As a result of the experiment, the calorific value of the cement paste with liquid red mud was lowered and delayed compared to the cement paste with neutralized red mud.

There is a need to analyze various factors in evacuation safety assessment of building in fire. In the current performance based design, evacuation safety assessment in case of fire is being conducted through the simulation as FDS and Pathfinder. However, the location and size of the door, the location of evacuation in the event of a fire are not considered when design. Accordingly, it is difficult to determine the worst case scenario considering the actual fire. Therefore in this study, in this study, we will propose an appropriate evaluation plan through simulation considering the worst-case scenario that may occur in case of fire.

In This study, we tried to review an efficient curing method in consideration of safety and constructability among the problems of winter construction. In other words, as a result of the mock-up test, the measured value of carbon monoxide was 0 ppm in the case of an electric hot air fan. Since there is no carbon monoxide, problems such as suffocation are expected to be solved. In terms of temperature characteristics, electric hot air fans exhibited high thermal efficiency performance with a slight difference in upper/lower temperatures compared to the existing ones. In the future, we plan to conduct thermal efficiency evaluation through actual site performance verification. We will propose an efficient curing method through applicability evaluation.

In the case of, the ignition of flammable external materials by the radiant flame and the accompanying fire in the upper layer are occurring every year, and in the case of the Flashover prediction formula, the limit is reached through the surface area of the space and the factor. Predicts heat release rate. In this study, the critical heat release rate of each prediction formula was calculated based on the ISO 9705 model.

During the construction work, many deaths and injuries have occurred in the formwork. This study aims to analyze the perceptions of construction workers about the disaster of formwork collapse. In this study, the IPA(Importance-Performance Analysis) technique was used to analyze the perception of construction workers and derive urgent factors for improvement. As a result of IPA analysis, the fourth quadrant factor needed to be improved first, and the second quadrant factor needed effort distribution. Therefore, it is judged that this study can be used as basic data for safety management and disaster prevention activities.

Recently, due to fires in high-rise residential and commercial buildings and apartments in Ulsan and Busan, the issue of evacuation safety in the event of a building fire is being closely watched. In the evacuation safety design for these building fires, it is important to secure evacuation routes considering the spatial characteristics of the building or the characteristics of the occupants and to take measures to protect the evacuation routes in order to ensure the safety of the occupants in the event of a fire. Although simulation is mainly used in Korea to assess the safety of evacuation, there is a big difference in that the Building Standards Act provides tools that can be calculated more than simulation in neighboring Japan. In addition to the evaluation method, which is called the "Building Law Assessment Methods" in Japan, the research team considered that it is important to know the process of evaluation in future domestic research, and investigated the contents of the evaluation process and wanted to apply it first to domestic buildings in the future.

The construction industry is an industry heavily dependent on manpower, and high-quality skilled workers are needed to ensure smooth construction. However, workers who entered the construction industry did not acquire professional skills or receive other education through apprenticeship education. In this study, the necessity of professional functional education and education plan were analyzed and presented in order to cultivate quality functional manpower.

In order to establish an evaluation method that can quantitatively evaluate the fire safety of existing buildings in Korea, a stochastic approach is needed to consider the extent of damage in the event of actual fire, along with the operation and installation of facilities. Accordingly, as a basic study for the establishment of fire safety assessment methods for buildings, this study aims to analyze the results of safety inspection and the degree of damage caused by the operation of fire doors and fire shutters in order to derive the reliability of fire doors and fire shutters. As a result, the results of inspection of fire shutters and fire doors and the results of operation using fire statisticians are as follows. As a result of the inspection, the positive rate of fire doors was about 82% and 98% of normal operation was derived from the fire investigation.

Universities that offer architectural engineering programs in Korea are making efforts to introduce innovation teaching methods to cultivate teamwork, creativity, flexibility of thought and practical skills needed for the Fourth Industrial Revolution. However, there is a lack of specific measures to support them. In this regard, this study investigated a method of application development for building construction courses applied with the innovation teaching methods. It mainly focused on 'improvement directions for existing learning management systems' and 'online learning support plans using the innovation teaching method' as research contents. It is expected that these improvement directions can be applied to the field of education through the development of mobile and web-based applications. In the follow-up research, the development of specific software for field application will be carried out.

This research is part of the research for unifying the mass concrete and utilizing the rate of super retarding agent. We analyzed the performance of super retarding agent 20℃ conditions. It was found that there was no deterioration in fluidity and air quality due to the change in the super retarding agent mixing rate. It was found that when super retarding agent was mixed up to 0.5 %, it was delayed for 22.3 hours at 20℃. Therefore in order to ensure the performance required at the site, the super retarding agent mixing rate must be determined by fully considering the situation at the site. In addition it will be analyzed that super retarding agent performance analysis at high temperature will be required in subsequent studies.

This paper attempted to examine the characteristics of heat of hydration and calorific value of concrete according to the formwork material in Hot weather environment. As a result of the experiment, it was found that there were no problems such as temperature cracking and delay in hydration reaction when a synthetic resin form was used.

Recently, interest in OSC(Off Site Construction) is increasing due to the trend of a decrease in skilled workers and an increase in labor costs. In this regard, PC(Precast Concrete) is being reviewed for apartments, the most common type of housing in Korea. As the biggest concern for PC apartment houses, civil complaints such as inter-floor noise and leakage were presented. In this study, the details of the joints were reviewed based on the past cases of PC apartments, and the details of the recently constructed or planned PC apartments were investigated. Through this, the leakage path in the past was analyzed through the existing research literature and data, and a discussion was conducted on the direction for a detailed proposal of an improved joint in the future.

The equation of end bearing capacity is applied differently depending on the type of pile, construction method, and load characteristics considering the construction standards. The bearing capacity equation of the design standard is presented in various ways according to the design conditions such as construction method and ground condition, etc. but, It does not reflect the ground strength according to the SPT-N value of weathered rock. This study analyzed the trend of allowable tip bearing capacity by pile diameter through about 480 dynamic loading tests conducted for the construction/quality management of piles for the last 6 years since 2015. The equation for the ultimate end bearing capacity per unit area according to the SPT-N value is presented. The proposed formula of ultimate end bearing capacity per unit area can be applied in the range of 15,000kN/m2 to 30,000kN/m2. The proposed formula, which complements the existing formula, enables pile design and construction/quality management.

Recently, there is a problem that is most important in constructing buildings and building materials. It is a harmful substance generated in buildings. These harmful substances are CO₂, radon and formaldehyde, volatile organic compounds generated from building materials. These are bad for the human body, may have a negative effect and cause large illnesses such as cancer. Recently built apartments have a high density, so there is a problem that harmful substances do not escape well. As a result, people's interest in indoor air quality is growing and in order to solve this problem and various researches are being conducted on the materials used for concrete pouring to find out how much the materials used adsorb harmful substances. this study uses carbon black as a material that can adsorb these harmful substances. The purpose of this study is to measure the bending strength, compressive strength, and to determine whether the paste containing carbon black can improve indoor air quality.

The purpose of this study is to evaluate the absorption ratio reduction of recycled coarse aggregate for concrete coated by polymer dispersions. The surface of recycled coarse aggregate is treated by polymer dispersion such as SBR and SAE with solid contents of 2%, 5% and 10%. From the test results, The minimum absorption ratio of the coated recycled coarse aggregate is 1.60 times smaller than that of uncoated recycle coarse aggregate. It is apparent that the absorption ratio of recycled coarse aggregate is much more improved by surface coating with polymer dispersions.

LEFC, a emotional concrete and one of light-transmitting concrete, has a characteristic of transmitting light, so its utility is great. In this study, in order to utilize LEFC under ultraviolet conditions, GST, a low-cost high-performance photocatalyst, was incorporated into the UHPC mix proportion. Specimens were prepared by applying ISO 22197-1. The test was conducted according to the standard and it was confirmed that the NO removal performance was over 50%.

In this study, the performance evaluation was performed by adding a polymer aqueous solution as a new additive of the red clay binder for use in the rammed earth construction method. The evaluation items were compressive strength and microstructure analysis. As a result of the experiment, the performance of the red clay binder was improved by efficiently bonding the silica particles by the polymerized polymer.

For modern people who spend 80% of the day indoors, indoor air quality is an important factor in their lives. Radon and fine dust, which are indoor air quality pollutants, cause various diseases and lung diseases, so a method is needed to reduce them. Therefore, this study intends to utilize the air pollutant adsorption properties of the carbonized sludge by using the carbonized sludge generated through drying and carbonization of the sludge. As a result of the experiment, it was shown that the concentration of radon and fine dust gradually decreased as the replacement ratio of carbonized sludge increased. The reason is that the carbonized sludge has the ability to adsorb fine dust and radon, so it is considered that it gradually decreases as the replacement ratio increases. Also, the compressive strength and flexural strength tend to decrease gradually. The reason for this is that the carbonized sludge has a number of internal voids, and as the replacement ratio increases, the internal voids increase and the strength decreases. If the refinement and strength of the carbonized sludge replacement ratio are supplemented, it is believed that it will be able to replace the existing finishing materials.

This study investigated the performance evaluation of polymer cement mortar for repairing concrete structures using calcium nitrite(Ca(NO₂)₂) and CO₂ nano-bubble mixing water to develop section-restoration methods for the repair and reinforcement of cracks. The evaluation items were strength and microstructure analysis at 28 days of age according to the change in the amount of calcium nitrite and the use of CO₂ nano-bubble water. As a result of the experiment, it was confirmed that the performance of polymer cement mortar for repairing concrete structures was improved by the generation of nitrite-based hydration products when calcium nitrite and CO₂ nano-bubble water were used.

In case of high temperature damage such as fire, the durability of concrete is reduced due to the collapse of internal pore tissue. Therefore, in this paper, we are going to analyze the pore structure of cement paste hardening agent using MIP analysis and build up 3D data produced using X-ray CT tomography. The test specimen is made of cement paste from W/C 0.4. As the temperature of heating increased, the amount of air gap and the diameter of air gap in cement paste increased. It is judged that the air gap structure inside cement collapsed due to the evaporation of the hydrate, gel count, capillary water, etc. inside the cement due to the high temperature.

Granting self-sensing performance in a building is an important performance to ensure the degree of damage and safety of the building. Since the current research is being conducted in the state before deterioration loss occurs, it is necessary to confirm whether the self-sensing performance is maintained even in the damaged conductive cement composite. As part of the study, electrical resistance characteristics were analyzed in conductive cement composites in which freeze-thawing and chemical corrosion occurred. As a result, it was found that the change in electrical resistance value due to freeze-thawing was not as large as 1%, and chemical corrosion occurred. It was found that the change in electrical resistance value of the tested specimen increased by about 10%.

When concrete is exposed to fire, the thermal decomposition of hydrates of Portland cement paste results in critical damage to the concrete structure of a building. Recently, nanosilica arose as the effective nano-additive which can enhance the thermal resistance of the cementitious materials. However, the mechanism of the enhancement was not elucidated specifically. In this study, we investigated the properties of calcium silicate hydrates(C-S-H)of the nanosilica incorporated cement paste after heating to different heating temperatures (200℃, 500℃, and 800℃) by 29Si nuclear magnetic resonance. The results showed that the polymerization of C-S-H of nanosilica incorporated samples was larger than ordinary cement paste after heating to 200℃, and C-S-H formed during heating process to 500℃ due to the pozzolanic reaction during heating process.

This study aims to find out the reason that tile adhesive(type III) for ceramic tile does not harden under some conditions especially high humidity even though long curing time. Bonding strength of adhesive between substrate and ceramic tile is evaluated depending on bonding conditions such as substrate kind(concrete, board), bonding material (tile adhesive, tile cement) and curing condition(humidity 50, 70%). Based on the results, this study aimed to establish the quality of tile adhesion strength under the relevant conditions.

The purpose of this study is to evaluate tensile performance of cementitious composites reinforced with steel fiber. The tensile performance of steel fiber reinforced cementitious composites is related to the tensile performance of reinforced fiber, and depends on the fracture or pull-out of fiber. Therefore, the tensile performance was compared and analyzed by conducting a direct tensile test on the tensile specimens of cementitious composites reinforced with hook-type steel fiber and amorphous steel fiber.

The present study examined the effectiveness of textile fabrics coated with nano-pore materials on removing the nitrogen oxide (NO_X) and sulfur oxide (SO_X) in the atmospheric environment. The tested approach is favorable for absorbing NO_X and SO_X, even under the washing condition.

This study examined the potentials for developing a biological coating material with high chloride resistance. The bacteria strains isolated were Halomonas alkaliphile, Halomonas venusta, and Sulfidobacter mediterraneus. Test results revealed that the developed approach is very promising in reducing the chloride ion diffusion coefficient of concrete.

In this study, as part of securing related data, water droplets were dropped on the upper part of the wooden board for flooring in an environment such as floor heating, and the degree of absorption according to the surface temperature change was tested. The test results showed that the contact angle of the surface was low (25℃→40℃) or the droplet was absorbed into the small plate and disappeared. The contact angle of the OSB and MDF was decreased within 30 minutes, but the surface water droplet was maintained longer than the plywood. This is because the surface is coated with hydrophobicity unlike the plywood, but moisture absorption in the cross section after the second processing will not be prevented and it will lead to defect occurrence problem.

The purpose of this study was to evaluate the shrinkage properties of a tile reinforced with epoxy resin, which has the advantages of high adhesion and low shrinkage, and causes a hardening reaction by chemical bonding with cement mortar. As a result, since the epoxy resin adhesive suppresses the moisture evaporation of the mortar, the drying shrinkage of the mortar itself is reduced, accordingly, the shrinkage of the tile itself is greatly reduced, and it is thought that it is possible to prevent a decrease in adhesion due to shear stress.

The climate on the Korean Peninsula has been warmed recently, abnormal weather conditions such as heat waves, cold waves, and tropical nights have been detected frequently. Precisely, the number of days with cold waves in the winter has increased, and rapid changes of temperature in the morning and afternoon have occurred frequently in the 2000s. Due to the previous phenomenons, this research is focused on evaluating the concrete's Chloride Penetration Resistance and Durability, and the difference of the resistance according to the W/C.

In order to expand the material recycling of waste plastics made of composite materials, it is necessary to develop the use of material recycling products and to secure their quality stability. In this paper, as a basic study to secure the stability of the quality of household waste plastic material recycling products, the quality characteristics of recycled materials according to the production period were compared and reviewed. In addition, the average tensile strength of the recycled products by production period for 4 months was 12.33 MPa, and the average density was 1.35 g/m3.

The purpose of this study is to explore the possibility of estimating optimum surface finish time of the fresh concrete placed at the job site by applying a surface hardness test meter(Durometer). Tests are carried out by measuring and comparing the Penetration resistance test and hardness test by Durometer. Penetration resistance tester and improved Durometer are similar, but the higher the temperature, the higher the setting time, and the higher the correlation was shown. When the hardness value of the improved Durometer is about 50 HD, it is found that the initial and 80 HD represent the end. It is expected that this will be useful in determining the finish time of the surface at the actual site.

In this study, in order to understand the needs for infrastructure services experienced by the public, we compared the level of infrastructure service satisfaction and analyzed the characteristics of infrastructure services by region. In this study, as a result of comparing the level of infrastructure satisfaction between regions, transportation and living infrastructure services were generally low. However, the characteristics of infrastructure services within the region are clearly different from the results of the infrastructure satisfaction between regions. Therefore, it is necessary to examine the level of infrastructure satisfaction within the overlooked region, and the satisfaction, improvement importance, respondent characteristics, and quantitative indicators need to be considered.

In modular construction, safety management is required to prevent the occurrence of risk factors such as lifting work and high place work due to the characteristics of the construction method. Therefore, this study is a basic study for safety management of modular construction, and the purpose of this study is to compare and analyze the classification system of modular construction derived by analyzing the construction process of the existing case. Based on the results of this study, the safety management classification system will be used in future research to derive safety management factors in modular construction.

As the concrete pouring work relies on manual work, there is a lot of room for automated equipment development. In this study, as a basic study on the development of an automated system for pouring concrete, the trend of patent applications by year, country and detailed technology was investigated. Related technologies were classified into screed automation, CPB automation, and concrete pouring integrated system to analyze patent application trends. As a result, since 1999, patent applications have been steadily in progress, repeating increases and decreases in Japan, Korea, the United States, and Europe. In addition, the growth stage of the market is in the early stages of maturity, and patent applications for related technologies are expected to continue. In the future, based on the patent application trend analyzed in this study, the development direction of the automated concrete pouring system will be reviewed and the redundancy of similar technologies will be reviewed.

In the construction industry, expectations for the Precast Concrete(PC) construction method are rising due to demands for high quality and productivity and social and environmental issues. However, although technical problems that occurred in the early stages of technology introduction have been solved, research related to proper construction management for PC construction methods has been relatively neglected and the advantages of PC construction methods have not been fully utilized. In this study, each group involved in PC works was surveyed to identify important management tasks affecting productivity of PC works to improve PC contruction management system. Based on factor analysis, 22 tasks were calssified into 5 management groups. The results of this study will be used to present a framework for the application of automation and information technology to improve the productivity of PC works.

In the budgeting guidelines, there are rules for calculating design fee and direct costs. However, only the design fee is calculated excluding the direct cost, which causes the cost to be insufficient. Therefore, this study is designed to analyze representative cases where direct costs are insufficient, draw out problems, and propose a way to improve design fees.

This study investigates the feasibility tp estimate the compressive strength at early age in hardened concrete by applying Durometer D type. The result of the experiment showed that the compressive strength reached 5MPa 6 hours, and 55 HD when the hardness was measured with the type D of the Duometer. Through this, it is expected that it will be possible to estimate the compressive strength of the initial age and measure it by the age of 28 when using the Durometer D type in the ready-mixed concrete, which will be applied in practice.

MEP layout and 3D Laser scanning are widely used equipment for displacement measurement in construction site. In this study, MEP layout and 3D Laser scanning were used to measure the lateral displacement of the same structure, and then the advantages and disadvantages of each were compared and analyzed. In general, it has been shown that MEP layout can save a lot of time compared to 3D Laser scanning. And it was found that the lateral displacement measurement results measured at a distance of 15m were similar to each other.

In Top-down sites, there are many open sections around the tower crane installed on the steel frame. The open section near the tower crane may cause slab cracks and deformation of the steel frame members installed in the open section due to earth pressure. Therefore, in the field, additional consideration during construction of the open section near the tower crane should be considered.

Damage to temporary facilities and structural members caused by excessive loads in the field continue to occur. If the load can be monitored in advance, the risk can be prevented. In this study, a load cell sensor is installed under the system support, and load data is wirelessly transmitted through a Bluetooth AP(wireless). Risk prediction system is proposed through an construction alarm when an abnormal load occurs through real-time multi-point monitoring by sensor location.

In the field of architecture, concrete and steel bars are the most common and popular combinations. The relationship between the two in a structure is a complementary good that increases in utility when consuming both materials at the same time. However, the combination of the two, which has been perceived as semi-permanent, often faces repairs or reconstruction without its lifespan reaching decades. There are a number of deterioration factors at work for the reason for this phenomenon. Among them, the neutralization of concrete in particular refers to the process in which calcium hydroxide inside concrete reacts with carbon dioxide and loses alkalinity, which creates a corrosive environment for rebars inside concrete, causing serious damage to concrete. In this study, we intend to use a multi-physical analysis program using finite element analysis method to analyze the degree of carbonation according to the internal temperature and concentration of carbon dioxide in concrete, thereby contributing to the prediction of long-term neutralization of concrete and the research related to measures for neutralization of concrete.

The bonding of steel bar to concrete is closely related to the roughness and corrosion degree of steel bar surface. The accelerated corrosion of concrete specimens with different reinforcement diameters was carried out in this test. Through the pullout test of the corroded concrete specimens, the relationship between the bond stress and the displacement of the corroded concrete specimens under the corresponding corrosion degree was obtained. The bond stress of reinforced concrete with different size and corrosion degree are compared and analyzed to find out the influence of corrosion on the bonding property of reinforced concrete.

In reinforced concrete adhesion studies, the demolition of the specimen is inevitably involved, and the studies conducted are limited to the macro load-displacement analysis. In order to establish an elaborate model for concrete bonding reinforced rebars, it is necessary to observe the rebar bonding behavior in the in-situ state. In this study, specially manufactured reinforcing bars, micro-UTM and 𝝁-computer tomography (𝝁CT) are used to observe reinforcing bars in the in-situ state. As a result of the monotonic pullout test of the processed reinforcing bar, maximum bond stress were shown to be 16.7MPa, which is slightly higher than the existing 10 to 12 MPa, and then the empty space inside the specimen in which the pullout test was conducted using 𝝁CT was confirmed. Through additional research, the fracture phenomenon of concrete excluding voids will be studied.