Title Early Age Strength of Concrete Using High Fineness Ordinary Portland Cement and Powdered Early Strength Admixture
Authors 이의배(Lee, Eui-Bae) ; 고정원(Ko, Jeong-Won) ; 유재강(Yoo, Jae-Kang) ; 김경태(Kim, Gyeong-Tae) ; 송동근(Song, Dong-Geun) ; 구경모(Koo, Kyung-Mo)
DOI https://doi.org/10.5659/JAIK.2020.36.7.163
Page pp.163-171
ISSN 2733-6247
Keywords high fineness; ordinary portland cement; early strength admixture; early age strength
Abstract Recently, studies on concrete that can develop early age strength at low temperatures have been conducted for the purpose of shortening the construction period in cold weather. In other studies, high fineness ordinary Portland cement or type Ⅲ high early strength Portland cement were used as a binder to develop early age strength. In addition, to further enhance the development of early age strength, a liquid chemical admixture was used. However, in this study, powdered early strength admixture was used instead of liquid early strength admixture to further stabilize the quality of concrete, and it is possible to keep the ratio of cement and admixture unchanged by premixing. In this paper, early age strength properties of concrete using premixed binder of high fineness ordinary portland cement and powdered early strength admixture were evaluated. Also, finally, the conditions that could satisfy the target strength of 5 MPa to remove gang form were analyzed. As a result, it was possible to get the target strength of 5 MPa within 18 hours if the curing temperature was 13 ℃ or higher, and it was possible to get the target strength of 5 MPa within 15 hours if the curing temperature was 15 ℃ or higher. The maturity value to reach the target strength of 5 MPa was calculated 363 ℃·hr. and 340 ℃·hr., respectively, for unit cement weight of 340 kg/m3 and 370 kg/m3.