• Journal of the Korea Institute of Building Construction
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• v.19 no.4
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• pp.307-312
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• 2019

Sludge generated in the production of ready-mixed concrete is classified as waste and processed at a high cost. In particular, small and medium-sized ready-mix manufacturer are burdened with such costs, and some companies are illegally processing them. Therefore, the purpose of this study is to suggest a method for recycled remicon sludge as a concrete block composition. When the remicon sludge is simply dried, the residual chemical admixture and ettringitee contained in the sludge are present, so that the compressive strength of the concrete block and the compressive strength after freezing and thawing are largely deteriorated to meet the quality standards of the concrete shore and retaining wall block It was not possible to do. As a method for satisfying the physical performance, it was found that the remicon sludge was calcined at a high temperature of about $900^{\circ}C$. to decompose ettringite and residual chemical admixture and then used it.

• Journal of the Korean Recycled Construction Resources Institute
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• v.1 no.3
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• pp.204-210
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• 2013

This study has focused on the possibility for recycling tailings from the Sangdong tungsten mine (TA) as admixture for concrete. TA has been accumulating for several decades in Sangdong, a region in Korea, and there is a growing demand for alternative uses for this hazardous substance. In particular, the use must be in accordance with the hazardous materials stipulations under the Korean waste control act. This study showed that TA presented pH of 8.0-9.3, 18.7-22.0% of water content, 2.7% of maximum ignition loss. The chemical composition of TA showed minute differences from each depth of sampling that represented approximately 50% of $SiO_2$ and 13% of both $Al_2O_3$ and $Fe_2O_3$. The chemical composition of Cd, Cu, Zn and Pb from mortar incorporating TA showed lower levels of hazardous materials which met the specifications of the waste control act in Korea. The TA mortar also appeared very effective for stabilizing/solidifying heavy metals particularly when used in conjunction with SG.

• Journal of the Korea Concrete Institute
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• v.17 no.1 s.85
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• pp.19-25
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• 2005

Recycling of waste materials in the construction Industry is a useful method that can cope with an environment restriction of every country. In this study, synthetic lightweight aggregates are manufactured with recycled plastic and fly ash with 12 percent carbon. Nominal maximum-size aggregates of 9.5 mm were produced with fly ash contents of 0, 35, and $80\%$ by the total mass of the aggregate. An expanded clay lightweight aggregate and a normal-weight aggregate were used as comparison. Gradation, density, and absorption capacity are reported for the aggregates. Five batches of concrete were made with the different coarse aggregate types. Mechanical properties of the concrete were determined including density, compressive strength, elastic modulus, splitting tensile strength, fracture toughness, and fracture energy. Salt-scaling resistance, a concrete durability property, was also examined. Compressive and tensile strengths were lower for the synthetic aggregates; however, comparable fracture properties were obtained. Relatively low compressive modulus of elasticity was found for concretes with the synthetic lightweight aggregate, although high ductility was also obtained. As nv ash content of the synthetic lightweight aggregate increased, all properties of the concrete were improved. Excellent salt-scaling resistance was obtained with the synthetic lightweight aggregate containing 80 percent fly ash.

• Journal of the Korea Concrete Institute
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• v.17 no.3 s.87
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• pp.329-334
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• 2005

The use of Polymer Concrete (PC) is growing very rapidly in many structural and construction applications such as box culverts, hazardous waste containers, trench lines, floor drains and the repair and overlay of damaged cement concrete surfaces in pavements, bridges, etc. However, PC has a defect economically because resin which be used for binder is expensive. Therefore the latest research is being progressed to replace existing resin with new resin which can reduce the high cost. Here, Polymer concrete using the recycled PET(polyethylene terephthalate) has some merits such as decrease of environmental destruction, decrease of environmental pollution and development of new construction materials. The variables of this study are amount of resin, curing condition and maximum size of coarse aggregate to find out mechanic properties of this. Stress-strain curve was obtained using MTS equipment by strain control. The results indicated that modulus of elasticity was increased gradually in an ascending branch of curve, as an increase of resin content. Compressive strength was the highest for resin content of $13\%$. And Compressive strength was increased as maximum size of coarse aggregate increases. The strain at maximum stress increases with an increase of resin content and size of coarse aggregate. For the descending branch of stress-strain curve the brittle fracture was decreased when it was cured at the room temperature compared to high temperature.

• Journal of the Korean Recycled Construction Resources Institute
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• v.11 no.1
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• pp.89-96
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• 2023

In this paper, a ferrosilicon by-product was evaluated to confirm the feasibility of recycling it as supplementary cementitious material of ordinary Portland cement in concrete. Three different levels of replacement ratio (10 %, 20 % and 30 % of total binder) were applied to find which is the most beneficial to be used as a binder. Ferrosilicon concrete was initially assessed at setting time and compressive strength. Durability was evaluated by the resistance to chloride penetration test(RCPT) and alkali-silica reaction(ASR) with a comparison to silica fume concrete due to their similarity in chemical composition. The porosimetry and X-ray diffraction analysis along with energy dispersive X-ray spectroscopy give information on the microstructural characteristics of the ferrosilicon concrete. It was found that 10 % ferrosilicon concrete has higher strength while 20 %, 30 % have lower strength than OPC concrete. However, chemical resistance to chloride attack is higher when replacement is increased. Compared to silica fume, the durability of ferrosilicon might be less efficient however, it is obviously beneficial than OPC. High SiO₂ content in ferrosilicon results in producing more C-S-H gel which could make denser pore structure. Most of the risk of alkali silica reaction to silicate binders through length change tests was less than 0.2 %, and both mortar using ferrosilicon and silica fume showed better resistance to alkali silica reaction as the substitution rate increased.Reuse of industrial waste rather than producing highly refined additives might reduce environmental load during manufacture and save costs.

• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.3
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• pp.228-236
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• 2015

In this research, the influence of painting materials and applying timing on carbonation and chloride resistances of high volume SCMs concrete was evaluated. As a durability improving method, comparative tests were conducted with painting materials of ERCO (emulsified refined cooking oil), RCO (refined cooking oil), WR (water repellent agent), and ERCO + WR and with painting timings of right after demolding, and 28 days after the wet curing. From the experiment results, in the case of carbonation and chloride resistance, the carbonation depth and chloride penetration depth were decreased when the painting materials were applied in 28 days of wet curing. Additionally, for painting materials, with the order of ERCO, RCO, ERCO+WR, and WR, the carbonation and chloride penentration was delayed. Hence it is considered that ERCO shows the most favorable performance of resistance against carbonation and chloride penetration.

• Land and Housing Review
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• v.10 no.4
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• pp.51-59
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• 2019

The government is encouraging the notice of obligatory reclaimed asphalt as a result of the economic and social positioning of green growth to reduce the amount of waste resources and to solve natural resource problems by recycling continuously generated waste resources. However, it is necessary to develop application guideline for each application to apply reclaimed asphalt to the site because quality control of the reclaimed asphalt is difficult and the specifications are ambiguous as well. Therefore, in this study, the mix design, quality test, performance test, and finite element analysis about reclaimed Asphalt Pavement were conducted to develop application guideline for reclaimed hot asphalt. The mix design was carried out for the comparative general hot mix asphalt mixture, the reclaimed hot mix asphalt mixture using the additive, and the reclaimed hot mix asphalt mixture without the additive. Indirect tensile strength and tensile strength ratio tests were used to characterize the reclaimed hot mix asphalt mixture. Using the results of dynamic modulus test and FWD test for KPRP analysis and finite element analysis, the performance life was evaluated for general pavement and pavement using recycled aggregate. Finally, the life cycle cost analysis was used to compare and analyze the economics of reclaimed asphalt concrete pavement.

• Advances in concrete construction
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• v.11 no.5
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• pp.409-417
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• 2021

The incorporation of non-biodegradable tyre waste in cement-based material has gained more interest towards sustainable construction these days. Crumb rubber (CR) from waste tyre is an alternative for sand replacement in low strength applications. Many researchers have studied CR cement-based materials produced by normal mixing (NM) method and reported a significant decrease in compressive strength due to CR. To compensate this strength loss, this research aims to study the innovative incorporation of CR in cement composite via the preplaced mixing (PM) method. In this investigation, cement composite was produced with NM and PM methods by replacing sand with 0%, 50%, and 100% CR by volume. The test results showed no significant difference in terms of densities of cement composite prepared with both mixing methods. However, cement composite prepared with PM method had lower strength reduction (about 10%) and lowered drying shrinkage (about 20%). In addition, the sound absorption coefficient and noise reduction coefficient of CR cement composite prepared by PM method were in similar range as those prepared with NM method. Overall, the results demonstrate that the PM method is promising, and the maximum replacement level of 50% is recommended for CR in the cement composite.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.3
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• pp.263-268
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• 2020

The purpose of this study is to investigate the damping properties of polyurethane composites incorporating waste tire rubber powder and preplaced coarse aggregates. Four types of polyurethane-based composites were manufactured, and longitudinal impact tests were performed. And vibration signals in the time domain and frequency domain were measured and values of damping ratio for each specimen were calculated. Test results showed that the damping ratios of polyurethane composites, in which the amount of polyurethane was reduced by 10.6% and 21.2% through incorporation of rubber particles, were 8.4% and 4.6% lower than that of pure polyurethane. The damping ratio of the polyurethane composite produced in a similar manner to the prepact concrete production method was found to be 22% lower than that of pure polyurethane, however, the amount of polyurethane was reduced by 50% and the stiffness was 25.7 times higher than that of pure polyurethane.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2003.10a
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• pp.157-161
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• 2003