Synergistic effect of cattle bone and rice husk ash on mechanical and microstructural properties of cement mortar

The production of cement is growing every year due to its higher consumption in the construction industries. Several studies have been carried out that focus on the possibility of alternative cementing materials such as Industrial and agricultural wastes. Rice husk is one of such agricultural residues and cattle bone is animal waste that are available but didn't get much attention as alternative cementing material. This study aimed to investigate the effect of partial replacement of cement by combining cattle bone ash and rice husk ash mix in cement mortar at 0%, 5% 10% 15% and 20% by volume of cement. The workability test, compressive strength, Ultrasonic Pulse Velocity, water absorption, and sulfate attack tests were conducted for different curing ages (3, 7, 28, 56, and 90 day). In addition, the morphology scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential thermal analysis (DTA), fourier transform infrared spectroscopy (FTIR) and Brunauer-Emmett-Teller (BET) surface area test, complete silicate analysis test was conducted. Compressive strength increases with an increment of from 0 to 10% replacement at 28 days of curing from 31.5 to 45.9 MPa and slightly decreased beyond 15-20% replacement with 39.9 MPa and 30.6 MPa. The result revealed that the mechanical performance of mortar indicated enhancement of calcium silicate hydrate gel, thus reduce the porosity of cement matric. Under scanning Electron Microscopy (SEM) image, mortar sample possessed a dense matrix with a widespread presence of calcium silicate hydrate (C-S-H) gels.