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Using replacement for cement to assure sustainability is critical as the raw materials (limestone, sand, shale, clay and iron ore) used in making cement are depleting. The use of agriculture waste byproducts to replace cement is becoming an economic option. Rice husk ash (RHA), rice straw ash (RSA) and wheat straw ash (WSA) which have pozzolanic properties are viable alternatives. A study on RHA, RSA and WSA were conducted to determine their suitability. From the various grades of concrete studied show that up to 15% replacement of OPC with RHA, RSA and WSA have the potential to be used as partial cement replacement (PCR), having good compressive strength, performance and durability. In particular, the utilization of as PCR material as PCR can contribute to sustainable construction.

In this paper an experimental study was made on the effects of using Rice Straw Ash (RSA) & Wheat Straw Ash (WSA) as partial replacements of cement in mortar. The objects were to produce Nano Silica (NS) form RSA & WSA as agricultural wastes by using chemical acids. Then, control specimens with Ordinary Portland Cement (OPC) was made and in other specimen’s cement were replaced with 5%, 10%, 15% and 20% of RS & WS ashes by weight of cement. The workability was measured by the slump test. The pulse velocity and the sorptivity were also computed. The compressive and tensile strengths were also estimated. Experimental result showed that it was feasible to produce silica from WSA by chemical activation method. Also, the highest compressive strength, tensile strength and sorptivity noticed at 15% WSA.