Pelletized fly ash aggregates use for making eco-friendly concrete

Abstract

Today Vietnam is facing a seriously environmental challenge in handling fly ash and bottom ash from coal power plants with annual emissions of up to 15 million tons. Using the coal ashes to produce building materials is considered a main solution for this issue. Due to shortage of natural aggregates, using the ashes as aggregates in concretes achieves many benefits. This paper presents research results of pelletizing fly ash to produce an aggregate for concrete. The fly ash aggregates had strength of about 3.1 MPa, apparent specific gravity of 2.1 g/cm3, bulk dry specific gravity of about 1450 kg/m3 and water absorption nearby 22%. The concrete made from a combination of fly ash and bottom ash aggregates had the density of about 2000kg/m3 and the compressive strength of 17.5- 46.3 MPa at 28 days. Moreover, the aggregates were also applicable to manufacture ACOTEC wall panel with properties met requirements of TCVN 11524:2016.