Experimental Research on Mixture Ratio and Mechanical Properties of Unburned Brick with Shell Ash and Fly Ash

Abstract

The unfired bricks which regarded as a new green wall material are produced by fly ash, shell ash (renewable resources), cement and lime as the main raw materials, and together with the chemical activator. The essential mixture ratio is designed on the experimental result of its mechanical properties and durability. The bricks are water conserved in the condition of normal temperature and pressure. We respectively research the compressive and flexural strength and frost resistance of the unburned brick. The results show that the optimum mixture ratio for unburned bricks are: fly ash 41%, cement 25%, lime 15%, shell ash 15%, gypsum 4%, SBR 3%, fiber 0.10%, water-reducing admixture 0.5%, sand cement ratio 0.5 and water cement ratio 0.3. We obtain the properties of unburned bricks that produced by vibration with the optimum mixture ratio. The minimum compressive strength of one brick more than 30MPa, the mass loss of one brick after 15 times freezing and thawing cycles is only 1%, and the compressive strength after frost reaches 26MPa, the overall performance of bricks can satisfy the requirement of " China Fly Ash Brick " standard.