Engineering properties of unfired building bricks incorporating various industrial wastes

Abstract

This paper studies the possibility of using a mixture of class-F fly ash (FA) and residual rice husk ash (RHA) for producing unfired building bricks (UBB) with the application of densified mixture design algorithm (DMDA) method. In this investigation, little amount of cement (5–10%) was added into the mixtures as binder substitution. Especially, unground rice husk ash (URHA) was used as a partial aggregate replacement (10–20%) in the mixtures. By following Vietnamese standard (TCVN 1451:1998), solid bricks of 220×105×60 mm in size were prepared for testing hardened properties including compressive strength, flexural strength, water absorption, and bulk density. The forming pressure of 35 MPa was applied to form the brick samples in the mold. Test results reveal that all of the brick samples achieved good mechanical properties. Additionally, compressive strength, flexural strength, and water absorption of brick samples were respectively in the range of 13.8–19.7 MPa, 2.3–3.3 MPa and 9.7–14.8% while the other properties of the bricks were well-conformed to corresponding Vietnamese standards. Furthermore, it was definitely proved many potential applications of FA and RHA in the production of the UBB.