Study on using high-volume fly ash from phu my thermal power plant to manufacture concrete bricks in infrastructure construction

Abstract

This paper presents the research results of using fly ash (FA) of Phu My thermal power plant with high content and southern raw materials to make concrete bricks in infrastructure construction. This concrete can achieve a 28-day compressive strength higher than 50 MPa. The mixing ratio to replace fly ash compared to the volume of binder is designed in 6 cases: concrete using 0 %FA; 30 %FA, 40 %FA, 50 %FA, 60 %FA, 70 %FA. With the fly ash content replaced at 0 %, 30 %, 40 %, 50 % compared to the tested binder, the 28-day-old concrete has an increased compressive strength from 55,2 MPa to 60,8 MPa; tensile strength when being split increased from 8,5MPa to 9,2MPa; the corresponding abrasiveness of concrete at the rate is 0,12; 0,20; 0,24 and 0,25 g/cm². With the replacement fly ash content at too high 60 %, 70 % compared to the binder, the values of these experimental parameters tend to decrease compared to the control sample. The study proposes that the reasonable mixing ratio of concrete is 50 % of cement, replaced by 50% of Phu My fly ash, to simultaneously meet the criteria of workability, strength, abrasion, and cost.