The properties of preplaced aggregate concrete technology contain the industrial waste-material and the various shapes and sizes of coarse aggregate

Abstract

The success of preplaced aggregate concrete technology depends on two main factors which are potential grout and coarse aggregate. This research was conducted experimentally to determine the effect of using two different fly ash sources as an alternative for the partial replacement of cement and several size and shapes of coarse aggregate on the compressive and tensile strength of PAC specimens. This involved the use of seven concrete mixes with a low water-cement ratio of 0.4 and cement to sand ratio of 1:0.75 to produce standard cylinder specimens of concrete containing rounded and crush aggregate. Moreover, fly ash was added at a dosage of 5% and 10% of cement weight while three shapes and sizes of a rounded and crushed aggregate at 20 mm, 30 mm, and a mixture of the two were also applied. The results showed the compressive strength of specimens with different sizes or a mix of rounded aggregate in PAC exhibited a similar performance with 30 mm of crushed coarse aggregate. Furthermore, the specimen with a higher content of calcium fly ash demonstrated a more rapid strength at an early age of seven days than those with lower content. Therefore, the partial replacement of cement with industrial waste material in the form of fly ash in preplaced aggregate concrete has the ability to save up to 10% of cement and also produce certain environmental benefits.