• Journal of the Korea Institute of Building Construction
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• v.15 no.2
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• pp.193-199
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• 2015

As a solution of both environmental issue of reducing carbon dioxide emission and sustainable issue of exhausting natural resources, in concrete industry, many research on recycling various by-products or industrial wastes as the concrete materials has been conducted. The aim of this research is feasibility analysis of additional reaction with ordinary Portland cement and flue gas desulfurization gypsum based on the blast furnace slag and recycled fine aggregate based mortar to achieve the normal strength range. Consequently, in the case of mortar replaced 10% FGD and 30% OPC for BS, 80% of plain OPC mortar's compressive strength was achieved. Furthermore, when the water-to-binder ratio is decreased to keep the practically similar level of flow, it is expected to be achieve the equivalent compressive strength to plain OPC mortar.

• Journal of the Korea Institute of Building Construction
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• v.16 no.2
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• pp.97-105
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• 2016

Recently, application case of the ultra rapid hardening concrete-polymer composite(URHCPC) are increasing to repair for the deterioration of pavement. But it is a major disadvantage that the main material is expensive and has environmental load. For these reasons, the development of the economic, eco-friendly materials is needed. Calcium Aluminate Composite (CAC), produced by rapid cooling of atomizing method with molten ladle furnace slag, is a material capable of improving the economic feasibility and reducing the environmental load of URHCPC. In this paper, the properties of CAC and gypsum mixed CAC (GC) as alternative materials of RSC according to the types of polymer dispersion were studied. The results were as follows; compressive strength, tensile strength, flexural strength, bonding strength and modulus of elasticity of the composites using CAC or GC showed higher values than those of plain proportion in 3 hour. In later age, they were at the same level as the general proportions. URHCPC using BPD as polymer dispersion had superior strength properties generally. But modulus of elasticity was the same level as the case of using a SBR latex. According to these results, CAC or GC can partially substituted for RSC to product the URHCPC. When URHCPC uses the BPD as the polymer dispersion, it can be improved performance.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.1
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• pp.80-87
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• 2011

Blast furnance slag cement is a cement manufactured with using industrial by-product and it can reduce $CO_2$ by replacing cement when same uit volume concrete is produced. But Blast furnance slag has a short point that early strength of concrete is not good in winter season and it can be used. So, in this study, as long as replacement ratio of Blast furnance slag to original portland cement is under 30%, developed cement, ecoment, improve early strength of concrete and it applied to constructoin site. As a result, it improves 37% in terms of 1-day strength, it reduces 6.7% in terms of $CO_2$ emission when $1m^3$ concrete was produced. The importance and applicability of study wll be expected to increase cosidering global effort and green growth-strategy in country for reducing greenhouse gases.

• Resources Recycling
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• v.29 no.1
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• pp.53-61
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• 2020

This study aimed to develop a foam concrete material for a ground repair system that has low strength and low fluidity by using an eco-friendly binder, which substitutes industrial by-products for more than 90% of cement. Basic properties were evaluated after substituting a small amount of calcium sulfo aluminate (CSA) for the binder to improve the sinking depth rate and volume change, commonly found when it had a large amount of industrial by-products. The substitution rates of CSA for the eco-friendly binder used for the foam concrete were 2.5, 5, and 10%. Fresh properties, hardened properties, pore structure, and hydrates were analyzed. Experimental results showed that using only 2.5% of CSA could improve the deep sinking depth which occurred when using an eco-friendly binder. As a result, the weight difference between the upper, middle, and lower parts of cast specimens was improved even after being hardened. The addition of CSA also contributed to the formation of small, uniformly sized closed pores and improved initial strength. However, when the proportion of CSA increased, the long-term strength decreased. However, it satisfied the target strength when 5% or less of CSA was used. The results of this study revealed that it was possible to manufacture foam concrete with low strength and high fluidity for repairing ground satisfying target qualities by adding 2.5% of CSA to the eco-friendly binder containing a large amount of industrial by-products.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.127-128
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• 2022

In order to realize carbon neutrality in the international society, research on supplementary cementitious materials(SCMs) has been actively conducted as a way to reduce carbon dioxide emissions in the cement industry. However, the use of SCMs causes problems of initial hydration delay and strength reduction due to the reduction of tricalcium silicate(C3S) in the cement clinker. Therefore, in this study, the initial hydration and basic characteristics of cement mortar were confirmed by adding a C-S-H based hardening acceleration to blended cement mixed with Portland cement, blast furnace slag, fly ash, and limestone power. As a result of the heat of hydration and compressive strength test, it was confirmed that when hardening acceleration was added, the initial reactivity was high, so the heat of hydration was promoted, and the initial strength was increased. It is considered to be due to C-S-H seeding effect. Therefore, it is judged that the use of C-S-H based hardening acceleration can supplement the problem of initial hydration delay of blended cement in Korea.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.9
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• pp.5861-5869
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• 2014

Existing studies of building exterior materials have focused on the colors or textures of cladding, and in terms of a design planning approach, have focused on the use of the environment and equipment and fire safety topics from an engineering perspective. As a result, little research has been done on performance guidelines for exterior materials, specifically according to the building type. Research into eco-friendly cladding materials is also in the rudimentary stage in a practical sense. In this study, the use of exterior materials over the last ten years in domestic construction was analyzed. The usage status of building exterior materials was evaluated quantitatively by frequency analysis, and its environmental performance is proposed through complex (qualitative + quantitative) analysis. The average value of the exterior material type number used for all analyzed buildings was 2.59. Glass, metal, stone, resin, cement, wood, and clay were used in that order with regard to the usage status. The analysis found that five of the materials satisfied the high efficiency and eco-friendly grading in terms of the four characteristics of an eco-friendly exterior. A list of eight eco-friendly elements was also proposed. The eco-friendly elements and characteristics of the exterior materials were derived to provide basic guidelines for domestic construction companies and design offices.

• Ecology and Resilient Infrastructure
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• v.2 no.2
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• pp.147-153
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• 2015

Various adverse effects can occur due to direct exposure from toxic substances when toxic materials are used to restore river ecosystems. Thus, this study performed analysis on the development of toxicity in terms of survival and abnormality rates using embryos of Bombina orientalis living in Korea to analyze the toxicity of materials used in the river projects. The results showed that the toxicity in cement (C group) was the strongest whereas the toxicity in plant-based polyurethane (P1 group) was the weakest. Survival rates of B. orientalis embryos were 100%, 94 - 95%, 66 - 89% and 0% in control, P1, polyurethane (P2) and C groups, respectively. Abnormalities of embryos were 10.5%, 5.3 - 10.5%, 26.3 - 27.8% and 35.7% in control, P1, P2 and C groups, respectively. Furthermore, we verified that having a sufficient curing time reduced toxic substances that were extracted. The above result suggest that cement and polyurethane hamper the early development of amphibians. In conclusion, it is highly important to review biological safety with respect to the selection of materials used to restore rivers. This study shows the importance of the selection of eco-friendly materials and processes.

• Journal of the Korean Wood Science and Technology
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• v.37 no.6
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• pp.537-545
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• 2009

The objective of this study was to investigate potential usage of environmentally friendly building materials, liquid mortar and dry cement mortar mixed with charcoal, based on the test of their physical and chemical properties. From the test results of physical and chemical properties of the liquid mortar mixed with charcoal, liquid mortar containing over 20% of charcoal, the consistency viscosity and the non-volatile content met a standard requirement. Drying time was delayed with increase in charcoal contents in the liquid mortar, however they were fully cured within 60 minutes in all treated levels. Other properties were acceptable at standard requirement. From the results, it was found that the proper charcoal addition level to the liquid mortar was 25%. In the results on dry cement, it was found that samples containing 5% of charcoal showed the maximum compressive strength, whereas samples containing over 20% of charcoal did not reach the minimum requirement of KS standard. Water retention ability constantly increased as the charcoal ratio increased. The conventional dry cement mortar adsorbed 59.5% of it, in the test of adsorption rate on ammonia gas, whereas cement mortar containing 10% of charcoal showed 71.6% of ammonia gas adsorption.

• Journal of the Korea Concrete Institute
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• v.25 no.3
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• pp.261-269
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• 2013

In this study, it was developed eco-friendly inorganic binding material concrete using ground granulated blast furnace slag and alkali activator (water glass, sodium hydroxides). Eight reinforced concrete beam using inoganic binding material concrete were constructed and tested under monotonic loading. The major variables were mixture ratio of alkali activator, type of admixture and admixture. Experimental programs were carried out to improve and evaluate the flexural performance of such test specimens, such as the load-displacement, the failure mode, the maximum load carrying capacity, and ductility capacity. All the specimens were modeled in scale-down size. The eco-friendly concrete using inorganic binding material encouraged alkali activation reaction was rapidly hardening speed and showed possibility as a high strength concrete. Also, the RC beams using new materials showed similar behavior and failed similarly with RC beam used portland cement. It is thought that eco-friendly inorganic binding material concrete can be used with construction material and product as a basic research to replace cement concrete. If there is application to structures in PC member as well as production of 2nd concrete product, it could be improved the productivity and reduction of construction duration etc.

• Journal of the Korean GEO-environmental Society
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• v.15 no.4
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• pp.61-67
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• 2014

With a view to resolving environmental problems of hazardous cement, this study seeks to identify the unconfined compressive strength and bending strength of the vegetation block designed herein by utilizing high-strength natural soil stabilizer instead of cement. Soil stabilizer is mainly made of mixture of short fiber extracted from natural fiber and lime, etc. Soil stabilizer reinforces the shearing strength of soil to improve block supportive power and durability while preventing flood and frost damages. For the unconfined compressive strength test, test pieces were prepared by mixing soil stabilizer and weathered soil in different ratios of 6 %, 12 % and 18 %. Experiments were carried out according to curing periods of 5th, 7th, 14th and 28th of the day. For bending strength test, blocks were made in the same mixture ratios as for the unconfined compressive test and tested for each stage. Also, to evaluate for the field applicability, proposed optimum water content considering the characteristics of the soil stabilizer. Permeability test result for the vegetation block, satisfied by the KS F 4419 quality standards.