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Asphalt로 피복된 Portland Cement를 使用한 Concrete의 諸性質
尹錫天,李昌甲,洪元杓,鄭秀永,南宰鉉 충남대학교 공업교육연구소 1982 論文集 Vol.5 No.1
The construction works with concrete has the potential problems of water tightness. The conventional treatments for water-tight concrete are not satisfactory in terms of strength and water tightness. This study was to investigate the effects and application of the asphalt-coated portland cement on water-proof of the concrete and its influences on the physical properties of the concrete. The asphalt-coated portland cement, which is hereafter referred to as ACPC, was made by coating ordinary portland cement with asphalt in the rate of weight ranging from 0.5 to 1.0 percent. In this process, Calcium Chloride and Sodium Silicate were tried as the hardening time accelerator for producing ACPC, and carbon black, talc and other materials were tested for their effectiveness as pore filler. The specimens were prepared and tested with the various amounts of additives as a variable factor to find the optimum material. The analysis was mainly focused at water tightness, physical properties of the concrete and working conditions. The major findings of this experiment are as follows ; 1) Water-proof Test ① The specimens of ACPC and ordinary portland cement(OPC) were tested under the pressures of 3 and 9 kilograms per square centimeter per 24hours respectively and compared. The OPC specimens showed considerable amount of leakaged water while the ACPC specimens were rated lower permeabilities of 89%/28days, 40%/56days and21%/84days under the abovementioned pressure conditions. The most successful composition for water-proof was identified as ACPC added with Calcium Chloride and carbon black. ② The ACPC demonstrated its superiority in absorption test. The absorption amount of OPC for l hour was greater than that of ACPC for 24hours. 2) Compressive Strength Test Four kinds of specimens of ACPC aging 7, 28, 56 and 84days were tested and compared for their respective results of OPC. The ACPC added with carbon black was lower than OPC in compressive strength in the case of curing ages of 7 and 28days but ACPC was superior to the OPC in the specimens aging 56 and 84days. The ACPC added with others except carbon black exposed their lower compressive strength in all circumstances compared with the OPC specimens. 3) Slump Test The slump of ACPC with various additives such as carbon black, talc or clay was 21.6 centimeter which was higher than the OPC of 18.4centimeter slump. This result concluded that ACPC was much favorable in workability in comparison with that of the OPC. The conclusions are summarized as follows; 1) The optimum mixture for water tightness and compressive strength of concrete was found at 0.5% of SACPC, Calcium Chloride and carbon black respectively at the rate of the weight of cement.
콘크리트의 壓縮强度에 미치는 굵은 골재 크기의 영향에 관한 基礎的 硏究
윤석천,박서규,남재현,김무한 충남대학교 공업교육연구소 1985 論文集 Vol.8 No.1
The purpose of this study is to research an effect of aggregate size on the compressive strength of concrete. Tests were, therefore, made in sixteen classes of concrete : maximum aggregate sizes of 5, 10, 20, 30^mm with water cement rations of 40% and 60% and with AEA°cement rations of 0.00% and 0.03% for each maximum aggregate size. The results of this experiment are showing the fellowing tendency. 1. Generally, with the range of this experiment program, the smaller maximum aggregate size becomes, the higher the compressive strength of concrete gets. 2. The decreasing tate of the compressive strength of concrete gets higher in lean mix concrete than in rich mix concrete at each age. 3. The compressive strength of concrete is developed faster with not only the increase of maximum aggregate size but also the decrease of water cement ratio. And it shows that the rate of the compressive strength development is higher in AE concrete in spite of water cement ratio.