Effectiveness of sewage sludge ash combined with waste pozzolanic minerals in developing sustainable construction material: An alternative approach for waste management

Utilization of the sewage sludge ash in fabricating the construction material would be an effective alternative approach under the sludge management scheme other than landfilling. The present investigation deals with the utilization of the recycled sewage sludge ash (SSA) combined with the quicklime (QL) and blast furnace slag (BFS) as a cementitious material in controlling the physical and mechanical performances of mortar. The mortar samples were prepared using the different amount of SSA, QL, BFS, and alkali activator (AA). The performance of the sewage sludge ash based mortar (SAM) was evaluated measuring the bulk density, apparent porosity, compressive strength, flexural strength, and shrinkage strain, etc. The result reveals that the higher dose of AA (50% weight w.r.t the volume of water used) and QL (20% w.r.t. weight of the total cementitious material) influences the mechanical strength of SAM. Additionally, the optimum dose of the BFS (10% w.r.t. weight of the total cementitious material) leads to yield a maximum compressive strength (31.3 MPa) of SAM. Finally, based on the analytical analysis, a model has been proposed to explain the overall performance of the SAM. Hence, the utilization of SSA (70%) combined with QL (20%) and BFS (10%) for the fabrication of mortar and concrete is assumed to be an effective alternative technique in developing sustainable construction material and waste management as well.