• Magazine of the Korea Concrete Institute
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• v.6 no.3
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• pp.190-200
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• 1994

The purpose of this research is to examine experimentally the mechanical properties and economics of No-fines concrete for its application to the low-rise housing construction. Basic mechanical properties of No fines concrete are studied by measuring of compressive, tensile strength and stress-strain relationship, and economics of it is compared with other materials in unit cost and wall construction cost. From the test results, it can be concluded that No-fines concrete has advantages of good workability, light weight and lower construction cost, even though it has lower strength and modulus of elasticity than normal conc:rt:te does.

• Magazine of the Korea Concrete Institute
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• v.7 no.3
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• pp.149-155
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• 1995

An experimental study was carried out to investigate the strength implovlng effect of stone dust in no fines concrete. The cement aggregate ratios of 1:6, 1:8 and 1:10 and several water-cemment ratios between 30% and 56% were chosen for the mix design of no-fines concrete. For the no-fines concrete with stone dust, the weight ratio of cement to stone dust 1:1 was adopted and super plasticizer, 1.5% of cement in weight, was used to obtain proper and workable state of concrete. The compressive and tensile strength test were performed and the results for the different mix designs were compared with each other. The results show that the compressive strength of no-fines concrete can be improved by 38% and the tensile strength by 17%~72% for the same w/c, when the same weight of stone dust as cement is mixed together.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.205-210
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• 2002

As the deposits of natural sands have slowly been depleted, it has resulted in an increase in manufactured fine aggregate (MFA). Standard specifications for fine aggregate for concrete contained in KS F 2558 permit a maximum of 7 percent finer than the No. 200 sieve (75${\mu}{\textrm}{m}$). Since the production process for MFA normally generates 10 to 20 percent of micro fines-which is defined as aggregates passing the No. 200 sieve (75${\mu}{\textrm}{m}$)-more than permitted by specifications, Excess fines must be removed by screening and/or washing operations. The amount of by-products will continue to grow as production increases with environmental discharge restrictions. This fundamental study focuses on experimental research for the adequacy of use of micro fines included in crushed aggregate using methylene blue test. Total of 63 types of sands from seven different rocks were tested. Based on the test results, the methylene blue test was turned out to be a good indicator of the quality of micro fines for concrete and a supplementary article and an amendment of the KS standard were recommended.

• Korean Journal of Agricultural Science
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• v.14 no.2
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• pp.373-383
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• 1987

No-fines concrete is concrete from which the fine aggregate fraction has been omitted. The concrete so formed, consisting only of coarse aggregate, cement, and water, has large voids uniformly distributed through its mass. This study was performed to obtain the basic data which can be applied to the use of no-fines concrete. The data was based on the properties of no-fines concrete depending upon various mixing ratios. The results obtained were summarized as follows. 1. Test result of the consistency, suitable water-cement ratio was increased with the increasing of mixing ratio. 2. At the suitable water-cement ratio, the highest strengths were showed. But it gradually was decreased with the increasing of mixing ratio and strengths are considerably lower than that of conventional portland cement concrete. 3. The relations between compressive and tensile strength were highly singnificant as a straight line shaped. The strength ratio was decreased with the increasing of mixing ratio and considerably lower than of conventional portland cement concrete. 4. Bulk density was decreased with the increasing of the mixing ratio, and was similar to that of the conventional portland cement concrete at mixing ratio 1:4. 5. The relations between strength and bulk density were highly significant as a straight line shaped. The decreasing ratio of strengths was higher than that of bulk density.

• Magazine of the Korean Society of Agricultural Engineers
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• v.37 no.1
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• pp.73-80
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• 1995

This study was carried out to investigate the engineering properties of no-fines con- crete, consisting only of coarse aggregate, cement and water. The used coarse aggregates were two, one is natural coarse aggregate grading 4.75~ lOmm, the other is synthetic lightweight coarse aggregate grading 3~8mm. The results of this study are summarized as follows; 1. The W/C ratio of each type was increased with increase of additional amount of coarse aggregate. 2. The unit weight of used ndtural coarse aggregate was shown 1.762~2.184g/cm$^3$, and synthetic lightweight coarse aggregate was shown 0.756 ~ 1 .348g/cm$^3$. 3. The ahsorption rate of used natural coarse aggregate was shown 8.4 ~ 9.4 %, and synthetic lightweight coarse aggregate was shown 17.0~42.4%. 4. The compressive, tensile and hending strength was decreased with increase of coarse aggregate, respectively. The compressive strength of natural coarse aggregate 1:3 was shown 309kg/cm$^2$. 5. The ultrasonic pulse velocity and dynamic medulus of elasticity of each type was de- creased with increase coarse aggregate, respectively. Also, the decreasing rate of the natural aggregate was larger than that of the synthetic lightweight coarse ag- gregate.

• Advances in concrete construction
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• v.7 no.2
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• pp.87-96
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• 2019

Self-compacting concretes (SCC) are highly fluid concrete which can flow without any vibration. Their composition requires a large quantity of fines to limit the risk of bleeding and segregation. The use of crushed sand rich in limestone fines could be an adequate solution for both economic and environmental reasons. This paper investigates the influence of quarry limestone fines from manufactured crushed sand on rheological, mechanical and durability properties of SCC. For this purpose, five mixtures of SCC with different limestone fines content as substitution of crushed sand (0, 5, 10, 15 and 20%) were prepared at constant water-to-cement ratio of 0.40 and $490kg/m^3$ of cement content. Fresh SCC mixtures were tested by slump flow test, V-funnel flow time test, L-box height ratio, segregation resistance and rheological test using a rheometer. Compressive and flexural strengths of SCC mixtures were evaluated at 28 days. Regarding durability properties, total porosity, capillary water absorption and chloride-ion migration were studied at 180 days. For the two test modes in fresh state, the results indicated compatibility between slump flow/yield stress (${\tau}_0$) and V-funnel flow time/plastic viscosity (${\mu}$). Increasing the substitution level of limestone fines in SCC mixtures, contributes to the decrease of the slump flow and the yield stress. All SCC mixtures investigated achieved adequate filling, adequate passing ability and exhibit no segregation. Moreover, the inclusion of limestone fines as crushed sand substitution reduces the capillary water absorption, chloride-ion migration and consequently enhances the durability performance.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.433-442
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• 2021

In this study, the properties of no-fines polymer concrete with different polymer binder contents were evaluated. The polymer concrete was formulated using a polymeric binder (unsaturated polyester resin), fly ash, and recycled coarse aggregate (60%) and crushed coarse aggregate (40%). The polymeric binder content (4.0-6.0wt.%) was used as an experimental variable because it dramatically affects both the cost-effectiveness and material properties. The results showed that the density, compressive strength, flexural strength both before and after exposure to freezing and thawing increased as the polymer binder content increased, while the absorption, void ratio, permeable voids, coefficient of permeability, and acid resistance (mass loss by acid attack) decreased as the polymeric binder content increased. In particular, even though the void ratio was 18.4% and the water permeability coefficient was 7.3mm/sec, the compressive strength and flexural strength were as high as 38.0MPa and 10.0MPa, respectively, much more significant than those of previous studies. Other properties such as absorption and acid resistance were also found to be excellent. The results appear to be rooted in the increased adhesion of the binder by adding a cross-linking agent and the surface hydrophobicity of the polymer.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.10a
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• pp.64-69
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• 1996

As Waste-concretes generated in construction field are increasing, it is becoming difficult and expensive to dispose them. For environmental reasons, many attempts have been made to find ways of reusing these materials. However, very little waste-concrete is currently recycled or reused anywhere on the world. Recycled concrete is mainly used as nonstabilized base of sub-base in highway construction. In this study, in order to promote the reuse of the waste-concretes, no-fines concrete blocks using recycled concrete aggregates were produced and their properties are evaluated. From the test results about strengths, pemeability, and durability, it is known that to use recycled aggregates for construction goods is promising and economical.

• Korean Journal of Agricultural Science
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• v.23 no.1
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• pp.120-130
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• 1996

Concrete is the most commonly used structural materials, but in concrete construction, its self-weight represents a very large proportion of the total load on the structure, and there are clearly considerable advantages in reducing the density of concrete. This study was carried out to investigate the stress-strain properties of no-fines synthetic lightweight concrete with synthetic lightweight coarse aggregates. The used synthetic lightweight coarse aggregate were two types, one was expanded clay with grading 3~8mm, the other is pumice stone with grading 4.75~10mm. The results of this study were summarized as follows ; The static modulus of elasticity of the synthetic lightweight concrete was $1.8{\times}10^5kg/cm^2$ at type CE using the expanded clay and $1.6{\times}10^5kg/cm^2$ at type CL using the pumice stone. The dynamic modulus of elasticity was $1.9{\times}10^5kg/cm^2$(CE) and $2.0{\times}10^5kg/cm^2$(CL). The dynamic modulus of elasticity was 10~30% larger than that of the static modulus of elasticity. The load-time curves of synthetic lightweight concrete were shown approximately similar to each other type except for added foaming agent. The stress-strain curves in uniaxial compressive of synthetic lightweight concrete were similar to each other.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.2 no.2
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• pp.62-69
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• 1999

This study was carried out to find out the capability of applying such materials as porous concrete, could be called environmentally friendly materials, for bringing vegetations. For verying the purpose of the experiments such materials as potland cement and slag cement, coarse aggravates(${\phi}25mm$, ${\phi}18mm$, ${\phi}13mm$) were mixed. In the voids of porous concrete peatmoss and chemical fertilizers were filled, and on the surface of concrete organic soils were adhered for seeding grasses. For testing compressive strength, pH, voids the 12($4mixed{\times}3times$) specimens were manufactured. As results, the compressive strength of porous concretes were from 59 to $267kg/cm^2$ depend on mixed ratios between cements and coarse aggregates. Voids of concrete were from 33% to 40% and the pH were varied pH 8-10.5. So the capability of planting vegetations was to be ascertained. The germination and growth of grasses were not good, but it could be found out that the capability of vegetations on the concretes. For generalizing these results and applying on the construction sites, it is necessary to verificate following studies for various conditions.