Preparation and properties of fired clay bricks with added wood ash

This study was designed to determine the effects of wood ash on the physical and mechanical properties of fired clay bricks. The clay bricks were fabricated with the addition of 0, 4, 8, 12, and 16% by weight of wood ash. Strength development of brick was cased by fired at 900, 1000, and 1100 degrees C for 40 min. The experimental results demonstrated that the physical property and strength of the fired clay bricks depend on the wood ash content and firing temperature. Higher wood ash content affected an increase in porosity and water absorption, while the bulk density of the clay bricks was reduced. The compressive strength of the clay bricks increased with an increase in the firing temperature or a decrease in the wood ash amount. The minimum compressive strength of fired clay bricks, in accordance with the ASTM strength requirements, is 17.2 MPa and was satisfied by bricks containing 4% added wood ash fired at 1000 degrees C and 1100 degrees C, which attained a compressive strength of 17.9 and 19.4 MPa, respectively. The study confirmed that wood ash is a material that can be used to add extra porosity during the production of raw clay bricks.