EXPERIMENTAL STUDY ON DRYING SHRINKAGE OF STRUCTURAL LIGHTWEIGHT CONCRETE USING FLY ASH CENOSPHERES

Abstract

This paper presents an experimental investigation of drying shrinkage of high-strength lightweight concrete (HSLWC) using fly ash cenospheres (FAC) as an aggregate to substitute fine sand with a designed density from 1200 to 1700 kg/m3 and a desired compressive strength from 30 to 80 MPa. Drying shrinkage for six months of FAC HSLWC was investigated considering the effect of various factors. These factors include the fine sand replacement with FAC contents of 0, 20, 30, 40 % by vol. of the concrete mixture, the binder content of 750 to 950 kg/m3, the water to binder ratio of 0.35 to 0.6, the shrinkage reducing admixture (SRA) content of 0, 2, 3 %wt. of binder, and the polypropylene fiber (PP) content of 0, 0.3, and 0.5 % by vol. of the concrete mixture. The experimental results show that the incorporation of FAC content compensated drying shrinkage of HSLWC, and the 182-day drying shrinkage of FAC HSLWC was lower than that of the reference sample without FAC. Besides, the addition of SRA and PP fiber was found effective in reducing the shrinkage of FAC HSLWC.