• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.25-28
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• 2005

This study shows the early quality improvement of concrete with calcium sulfa aluminate(CSA). For the properties of slump, plain concrete incorporating BS $35\%$ and UP $15\%$ resulted in high fluidity compared with OPC without any admixture. As displacement ratio of CSA increased. the fluidity decreased. The fluidity also declined with setting time. Increase of incorporation ratio of CSA declined bleeding and accelerated setting time. Importantly, using more CSA helped to improve early compressive strength and decrease drying shrinkage. In term of water curing, drying shrinkage hardly ever occurred.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05b
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• pp.369-372
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• 2005

This study is about physical properties of concrete with changing displacement ratio of calcium sulfa aluminates(CSA) type admixture. Firstly, test shows that as displacement ratio of CSA increases and setting properties changes, fluidity and air contents decreases. In water to binder ratio 35$\%$ and 45$\%$, concrete using the cement replacing CSA 4$\%$ by volume shows that bleeding decreases 94.7$\%$ and 74.3$\%$ respectively, compared with plain concrete. In addition, setting time was promoted around 3 to 6 hour and 1 to 4 hour respectively. For harden concrete, increase of displacement ratio caused tendency of higher compressive strength as OPC has at early age. Replacing higher CSA admixture led to reduce of drying shrinkage.

• Magazine of RCR
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• v.9 no.2
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• pp.38-45
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• 2014

• Journal of the Korean Ceramic Society
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• v.37 no.6
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• pp.576-582
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• 2000

Two type of expanding cement generally referred to as CSA with Hauyne(3CaO 3Al2O3 CaSO4) and Quick lime(CaO). Hauyne is formed to ettringite when there are presented with CaO and CaSO4, and CaO reacts wtih water to form Ca(OH)2. REcently, the mechanism of compensation and expand mortar or concrete tend to same and it has been used improving on its shrink property. The volume of cement paste varies with its water content shrink with drying and re-wetting. Concrete and mortar works are required shrinking compensation and expansion properties to reduce of potential crack. The use of expansion cement may improve on its shrinking volume changes. CSA dosages for shrinking compensation limited by cement weight, but obtained difference expansion rate with varied W/C or inorganic admixture. This paper studies expansion rate according to expansion cement dosages, water and inorganic admixtures as Silica fume. Therefor, the expansion factor has to considered before the application.

• Journal of the Korean Ceramic Society
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• v.53 no.2
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• pp.215-221
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• 2016

In this study, the utilization of the by-products of various industries was examined using raw materials of CSA high-functional cement such as coal bottom ash, red mud, phosphate gypsum, etc. Technology to improve energy efficiency and reduce $CO_2$ was developed as part of the manufacturing process; this technology included lower temperature sintering ($150{\sim}200^{\circ}C$) than is used in the OPC cement manufacturing process, replacement of CSA cement with the main raw material bauxite, and a determination of the optimum mix condition. In order to develop CSA cement, a manufacturing system was established in the Danyang plant of the HANIL Cement Co. Ltd., in Korea. About 4,200 tons of low purity expansion agent CSA cement (about 16%) and about 850 tons of the lime-based expansion agent dead burned lime (about 8%) were produced at a rate of 60 tons per hour at the HANIL Cement rotary kiln. To improve the OPC cement properties, samples of 10%, 13%, and 16% of CSA cement were mixed with the OPC cement and the compressive strength and length variation rate of the green cement were examined. When green cement was mixed with each ratio of CSA cement and OPC cement, the compressive strength was improved by about 30% and the expansibility of the green cement was also improved. When green cement was mixed with 16% of CSA cement, the compressive strength was excellent compared with that of OPC cement. Therefore, this study indicates the possibility of a practical use of low-cost CSA cement employing industrial wastes only.

• Journal of the Korea Concrete Institute
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• v.12 no.1
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• pp.79-88
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• 2000

Usually, the expansive additives is used to prevent the occurrence of drying shrinkage in concrete. However it may sometimes be over-added in field due to the insufficient cognition of constructor's, which may cause the serious problems in concrete structures. In this study the experiments are performed to present the expansion properties of concrete by varying the water to binder ratios, unit contents of expansive additives and curing conditions. By the results, the strength showed an increase with the addition of expansion additives from 30kg/㎥ up to 50kg/㎥, and a great decrease by contraries if the larger amount are added. Also the more the expansion additives were used, the more length change occurred in concrete. In view of the curing conditions, the concrete by air cured appeared a little expansion even the unit expansion additives increased, which showed an opposite inclination of that with standard curing. This could be explained by the less occurrence of hydration in air condition which also lead to the little expansion of concrete. Hence the expansion concrete to be cured in water or moisture condition became an especial important thing. concrete using expansive additives showed that high expansion was taken place with the rise of temperature.

• International Journal of Concrete Structures and Materials
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• v.10 no.sup3
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• pp.97-108
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• 2016

When the energy performance of concrete is substantially higher than that of normal type concrete, such concrete is regarded as energy efficient concrete (WBSCSD 2009). An experimental study was conducted to investigate mechanical properties of energy efficient concrete with binary, ternary and quaternary admixture at different curing ages. Slump test for workability and air content test were performed on fresh concretes. Compressive strength, splitting tensile strength were made on hardened concrete specimens. The mechanical properties of concrete were compared with predicted values by ACI 363R-84 Code, NZS 3101-95 Code, CSA A23.3-94 Code, CEB-FIP Model, EN 1991, EC 2-02, AIJ Code, JSCE Code, and KCI Code. The use of silica fume increased the compressive strengths, splitting tensile strengths, modulus of elasticities and Poisson's ratios. On the other hand, the compressive strength and splitting tensile strength decreased with increasing fly ash.

• Journal of the Korea Concrete Institute
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• v.25 no.4
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• pp.371-379
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• 2013

This paper investigates the cracking and tension-stiffening behavior of 100 MPa shrinkage-compensated strain-hardening cement composite (SHCC) and conventional concrete tie elements in monotonic and cyclic tension. Strain and surface crack formation of tension ties were monitored with two strain displacement transducers and a photo microscope with a lens of magnification 50 times. Three different cement composites such as conventional concrete, shrinkage-compensated SHCC, and normal SHCC were used in the tie specimens to investigate the influence of the cement composite type on the tension stiffening and cracking behavior. Test results indicated that initial shrinkage of the ultra high-strength cement composites is greatly reduced as the 10% replacement of cement by the shrinkage-compensating admixture based on calcium sulfo-aluminate (CSA). The test results on the SHCC tension ties showed that the first cracking load decreases proportionally to the initial shrinkage strain. Reinforced ultra high-strength SHCC ties with the initial shrinkage compensation exhibited improved tension stiffening and smaller crack spacings, i.e. the reduction in crack width. Cyclic loading did not have a significant effect on tension stiffening and cracking behavior of tension ties with normal concrete and SHCC materials.