• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.4A
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• pp.603-609
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• 2008

The recycled aggregates which were produced from the waste concretes have the disadvantages of inferior properties for natural aggregate. Therefore, in order to reuse the recycled aggregate it must be solved to improve the quality of recycled aggregate. In this study, the quality of recycled aggregate was improved by the surface treatment method using the colloidal silica solution. And, in order to examine the possibility of reusing the surface coated recycled aggregate in constructing concrete structures, we studied the mechanical properties and durability of the concrete using the surface coated recycled aggregates and the other concrete.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.137-138
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• 2020

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.

• International Journal of Concrete Structures and Materials
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• v.8 no.2
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• pp.165-172
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• 2014

Recycled coarse aggregate (RCA) made from waste concrete is not a suitable structural material as it has high absorption of cement mortar, which adheres on the aggregate surface and on the tiny cracks thereon. Therefore, when using RCA made from waste concrete, much water must be added with the concrete, and slump loss occurs when transporting. Hence, its workability is significantly worse than that of other materials. In this study, surface of RCA was coated with water-soluble polycarboxylate (PC) dispersant so that its characteristics improved. Each possibility was evaluated: whether its slump loss can be controlled, by measuring its workability based on the elapsed time; and whether it can be used as a structural material, by measuring its strength. Moreover, the carbonation due to cement mortar adhesion was measured through a carbonation test. As a result, RCA coated with PC dispersant was found to be better than crushed coarse aggregate and RCA when the physical properties of the fresh concrete and the mechanical, durability of the hardened concrete were tested.

• Journal of the Korea Institute of Building Construction
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• v.15 no.6
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• pp.561-567
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• 2015

The research, in order to enhance the quality of recycled aggregate, was carried out the quality characteristics test of the recycled aggregates by applying the four kinds of surface treatment using a colloidal suspension of approximately 5nm~60nm particle size with the alkalinity of pH 10.2. The quality tests of recycled aggregate have been processed by specific gravity, water absorption, porosity, surface properties, and the compression and tensile tests. The colloidal suspension was coated effectively the surface of the old cement mortars of recycled aggregate with a constant thickness by colloidal suspension is being applied to the recycled aggregate surface under constant pressure of 100kpa and then it was dried in at $60^{\circ}C$. The surface treatment method by the Method C out of 4 kinds of surface treatment improved effectively the quality of the recycled aggregates, whereby it obtained the best compressive strength and tensile strength of the recycled aggregate concrete.

• Computers and Concrete
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• v.19 no.5
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• pp.451-455
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• 2017

Technological advancements in the field of building materials are achieved day by day. In this study, a new lightweight concrete aggregate is produced by mixing certain rates of colemanite (0%, 7.5%, 12.5%, 17.5%), cement and coating the surface of pumice aggregate with this mixture. Thin aggregate sections are analyzed with specific gravity, unit weight, water absorption, impact, and crushing experiments. In this way, the production of cement and cement+colemanite coated lightweight concrete aggregates is investigated and an opinion on the likely behavior of these concrete types is provided.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.1
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• pp.111-116
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• 2022

Recently, building structures tend to be super high-rise and large-scale with the development of concrete technology. When high-rise building is constructed of reinforced concrete structure, it has a disadvantage that its own weight increases. Light weight aggregate(LWA) was developed to compensate for these shortcomings. Manufacturing concrete using these light weight aggregates has the advantage of reducing the self weight of the reinforced concrete structure, but has a disadvantage in that the strength of the concrete is reduced. In this study, an experimental study was conducted to investigate the strength characteristics of hardened cement according to the presence or absence of surface coating of lightweight aggregates. As a result, in terms of compressive strength, the surface-coated lightweight aggregate exhibited higher strength than the uncoated lightweight aggregate. Also, it was considered that this is because the interfacial voids of the surface coated lightweight aggregate mixed cement hardened body were filled with blast furnace slag fine powder particles.