Application of Enzyme to Clay Brick and its Effect on Mechanical Properties

In this study, the application of an enzyme to clay bricks with different clay contents is described. The compressive strength test results for 7, 14, 21, and 28 days curing time, water absorption and dry density are reported. The enzyme brick with an 85/15 clay/silt ratio by weight exhibited higher strength in the 28-day test, with an average value of 6.89 MPa. Clay soil with a more specific surface area had a better chance of undergoing an ionic reaction with the enzyme to increase density and strength. Less water absorption, less porosity and higher density were also observed in brick with a higher clay proportion. Generally, the average compressive strength of the enzyme clay brick was over 5.50 MPa after a 28 day curing period and thus satisfied the specific limit of 5 MPa, which is the minimum standard for British common brick. SEM-EDX with the help of Matlab image processing verified that the enzyme facilitated the formation of bonds and a cross-link structure that benefited the strength and stability of clay brick.