Chemical composition and physicomechanical characteristics of sawdust ash blended cement

Abstract

The production of blended cement by incorporating sawdust ash (SDA) in Ordinary Portland Cement (OPC) clinker, during manufacturing of cement was investigated. Sawdust was collected from sawmill industry at Olope Marun, Ogbomoso, Oyo State, Nigeria. It was burnt to ash and then added as percentage replacement for OPC clinker. Chemical and physical properties of both SDA and OPC clinker were determined. The production of the SDA – blended cement was carried out by intergrinding 5–25% by weight of SDA with OPC clinker during cement manufacturing. The blended cement produced was analyzed for chemical composition and physical properties. The chemical compositions of SDA – blended cement with 5–25% SDA replacement were 19.96–22.52% for silicon oxide, 5.57–5.72% for aluminum oxide, 3.47–3.63% for iron oxide, and 65.39–57.28% for calcium oxide. The physical properties of SDA – blended cement were 5–7 mm for soundness, 391–410 m2/kg for fineness, 27.6–30.0% for consistency, 45–160 min for initial and 75–210 min for final setting time, 2.5–2.2 for specific gravity, and 1.33–1.45 for loss on ignition. The compressive strength of blended cement with 5–25% SDA replacement ranged from 5.2 to 9.9, 11.2–27.8, 13.9–44.0, 14.3–56.0, 15.8–58.9, 20.4–62.4, and 23.6–65.2 N/mm2 for 1, 3, 7, 14, 28, 56, and 90 days, respectively while the flexural strength ranged from 1.8 to 2.3, 2.5–5.3, 2.8–6.3, 3.4–7.4, 3.5–8.9, 3.9–10.1, and 4.1–11.5 N/mm2, respectively. The partial replacement of OPC clinker with SDA during cement manufacturing was established. A maximum replacement level of 15% by weight of cement gave desirable engineering properties.