• Magazine of the Korea Concrete Institute
• /
• v.10 no.4
• /
• pp.171-182
• /
• 1998

Vibration-controlled concrete has been developed by using various concrete mixtures, such as latex, rubber powders, plastic resins and polystyrene(styrofoam). As part of the recycling research of obsolete aged tires and plastic materials, various vibration-reducing mixtures are used for 10 concrete panels having above 200 kg/cm$^2$ in uniaxial compressive strength. Plywood box with sand uniformly saturated by the raining device has been used for the analysis of the impact wave, of which data have been transfered by the FFT technique to comparatively investigate damping ratios of 10 concrete panels.According to wave propagation analysis on vibration-controlled concrete for this research, it can be concluded that Latex concrete has relatively larger damping ratios than those for noncontrolled normal concrete in a similar compressive strength

• Computers and Concrete
• /
• v.28 no.6
• /
• pp.567-583
• /
• 2021

The use of waste materials as a binder or aggregate in the concrete mixture is a great step towards sustainability in the construction industry. Waste rubber (WR) can be used as coarse and fine aggregates in concrete and improves the crack resistance, impact resistance, and fatigue life of the produced concrete. However, the mechanical properties of rubberized concrete degrade significantly by replacing the natural aggregate with WR. To have accurate estimations of the mechanical properties of rubberized concrete, two machine learning methods consisting of artificial neural network (ANN) and neuro-fuzzy system (NFS) were served in this study. To do this, a comprehensive dataset was collected from reliable literature, and two scenarios were addressed for the selection of input variables. In the first scenario, the critical ratios of the rubberized concrete and the concrete age were considered as the input variables. In contrast, the mechanical properties of concrete without WR and the percentage of aggregate volume replaced by WR were assumed as the input variables in the second scenario. The results show that the first scenario models outperform the models proposed by the second scenario. Moreover, the developed ANN models are more reliable than the proposed NFS models in most cases.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2006.05a
• /
• pp.90-93
• /
• 2006

Buried pipeline is a indispensable factor of leading smoothly a society as a primary role. Recently, as a matter of convenience of construction and the economical purpose, the use of Precast Concrete products quickly increased. But there was various damage forms in a part of joint of Precast Concrete buried pipeline. The purpose of this study is to propose the new type of the flexible rubber packing material (EF) which could resist a permanent deformation of the ground or an earthquake and to investigate its safety together with effectiveness as conducting experiment and analysis.

• Computers and Concrete
• /
• v.12 no.5
• /
• pp.651-668
• /
• 2013

Concrete structures need repairing due to various reasons such as deteriorative effects, overloading, poor quality of workmanship and design failures. Cement based repair mortars are the most widely used solutions for concrete repair applications. Various factors may affect the bond strength between concrete substrate and repair mortars. In this paper, the effects of polymer additives, strength of the concrete substrate, surface roughness, surface wetness and aging on the bond between concrete substrate and repair mortar has been investigated. Full factorial experimental design is employed to investigate the main and interaction effects of these factors on the bond strength. Analysis of variance (ANOVA) under design of experiments (DOE) in Minitab 14 Statistical Software is used for the analysis. Results showed that the interaction bond strength is higher when the application surface is wet and strength of the concrete substrate is comparatively high. According to the results obtained from the analysis, the most effective repair mortar additive in terms of bonding efficiency was styrene butadiene rubber (SBR) within the investigated polymers and test conditions. This bonding ability improvement can be attributed to the self-flowing ability, high flexural strength and comparatively low air content of SBR modified repair mortars. On the other hand, styrene acrylate rubber (SAR) modified mortars was found incompatible with the concrete substrate.

• Computers and Concrete
• /
• v.27 no.3
• /
• pp.185-197
• /
• 2021

Throughout the previous years, many efforts focused on incorporating non-biodegradable wastes as a partial replacement and sustainable alternative for natural aggregates in cement-based materials. Currently, rubberized concrete is considered one of the most important green concrete materials produced by replacing natural aggregates with rubber particles from old tires in a concrete mixture. The main benefits of this material, in addition to its importance in sustainability and waste management, comes from the ability of rubber to considerably damp vibrations, which, when used in reinforced concrete structures, can significantly enhance its energy dissipation and vibration behavior. Nowadays, the literature has many experimental findings that provide an interesting view of rubberized concrete's dynamic behavior. On the other hand, it still lacks research that collects, interprets, and numerically investigates these findings to provide some correlations and construct reliable prediction models for rubberized concrete's dynamic properties. Therefore, this study is intended to propose prediction approaches for the dynamic properties of rubberized concrete. As a part of the study, multiple linear regression and artificial neural networks will be used to create prediction models for dynamic modulus of elasticity, damping ratio, and natural frequency.

• Steel and Composite Structures
• /
• v.38 no.4
• /
• pp.399-414
• /
• 2021

This paper aims to verify the feasibility of rubber rings to mitigate the shear concentration in perfobond connector (PBL) groups. Firstly, modified push-out tests for five specimens with four holes were conducted to investigate the effects of rubber rings on the shear mechanism of PBL groups. The test results showed that by employing rubber rings on partial holes, more shear forces were distributed to the holes without rubber rings. The rubber rings significantly improved the slip ability of the specimens, and the ductility of PBL groups is dependent on the number and thickness of rubber rings. Subsequently, three-dimensional numerical models were established and validated by the experimental results. According to the plastic strain distribution in concrete dowels, the action principle of rubber rings in PBL groups was explained. Furthermore, the parametric study was conducted to investigate the influential factors on shear distributions, including the width of steel plates, the hole spacing, the number of holes, the rubber ring thickness, and the positions of rubber rings. The parametric analysis results showed that the redistribution of shear forces is significantly affected by the rubber rings with the smallest thickness. By properly employing rubber rings in PBL groups, the shear forces of holes are more even. Finally, an analytical model for PBL groups with rubber rings was proposed to predict the shear distribution at the serviceability stage.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 1998.10a
• /
• pp.180-185
• /
• 1998

The study was conducted to evaluate the fundamental properties of waste tire asphalt concretes using polymer modified hinder that were made by dry process. The specimens of four types of polymer modified asphalt concretes were prepared, then Marshall test and indirect tensile strength tests were performed on these samples. The results showed that polymer modified waste tire rubber asphalt concrete was acceptable for the material of asphalt pavement surface layer.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1991.10a
• /
• pp.99-106
• /
• 1991

Result of an experimental study on the manufacture, the mechanical properties and waterightness of pitch-based carbon fiber reinforced fly ash.cement composites are presented in this paper. The carbon fiber reinforced fly ash.cement composites using early strength cement, silica powder and a small amount of stylene butadiene rubber latex are prepared with carbon fiber, foaming agents and mixing conditions. As a result, the mechanical and plysical properties such as compresive, tensile and flectural strengths, watertightness and cement composites are improved by using a small amount of stylene butadiene rubber latex.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.16 no.4
• /
• pp.69-78
• /
• 2012

This paper study on the physical property of naturally vulcanizing waterproofing synthetic rubber sheet for the underground concrete wall. In order to finding the naturally vulcanizing time, the relation of vulcanizing time and tensile strength is analysed from non-vulcanizing to naturally vulcanizing time. Physical tests such as tensile strength, tear strength: etc., under the thermal environment temperature at $-20^{\circ}C$, $-10^{\circ}C$, $20^{\circ}C$, $60^{\circ}C$. The result of experiment show that the developed rubber sheet has the delay time about 85 days and the curing time about 35 days. The tensile strength increased by about 692% and coefficient of expansion decreased by about 10% which value can be sufficiently compensate the demerit of vulcanized rubber sheet. Also, all of the physical properties of the naturally rubber sheet satisfy the KS standard and compare to the vulcanized rubber sheet, the developed naturally rubber sheet have excellent durability.

• Computers and Concrete
• /
• v.33 no.1
• /
• pp.41-53
• /
• 2024

Under constant and cyclic axial compression, square composite short columns reinforced with Self Compacting Concrete (SCC) added with scrap rubber infilled inside steel tubes and with different types of concrete were cast and tested. The test is carried out to find the effectiveness of utilizing an aggregate manufactured from industrial waste and to address the problems associated with the need for alternative reinforcements along with waste management. The main testing parameters are the type of concrete, the effect of fiber inclusion, and the significance of rubber-infilled steel tubes. The failure modes of the columns and axial load-displacement curves of the steel tube-reinforced columns were all thoroughly investigated. According to the test results, all specimens failed due to compression failure with a longitudinal crack along the loading axis. The fiber-reinforced column specimens demonstrated improved ductility and energy absorption. In comparison to the normal-weight concrete columns, the lightweight concrete columns significantly improved the axial load-carrying capacity. The addition of basalt fiber to the columns significantly increased the yield stress and ultimate stress to 9.21%. The corresponding displacement at yield load and ultimate load was reduced to 10.36% and 28.79%, respectively. The precision of volumetric information regarding the obtained crack quantification, aggregates, and the fiber in concrete is studied in detail through image processing using MATLAB environment.