Nghiên cứu nâng cao cường độ tuổi sớm của bê tông nhẹ chịu lực sử dụng hàm lượng lớn xỉ hạt lò cao nghiền mịn

Abstract

This paper presents the experimetal results on the influence of chemical additive, i.e. Ca(NO¬3)2, on the compressive strength of structural lighweight concrete (LWC) containing high volume ground-granulated blast-furnace slag (GGBFS). Structural LWC using 27% (by vol. of concrete mixture) fly ash hollow microspheres, also known as cenosphere (FAC) is used up to 27% by volume of concrete mixture with a density in the range from 1.600 to 1.900 kg/m3, compressive strength over 40 MPa. Achieving high early age compressive strength is difficult and challenging for lightweight concrete with high volume GGBFS. Therefore, the present study focused on the influence of Ca(NO3)2 on the strength development (under curing condition of 27 ± 2oC and relative humidity of 60 ± 5%) of structural LWC containing 50, 65 to 80% GGBFS (replacing cement content by weight). The experimental results show that the addition of Ca(NO3)2 enhanced the early-age compressive strength of structural LWC up to 11,6% and 9,0% at the age of 3, 7 days, respectively.