Chemical and Physical Characteristics of Blended Cements Produced from Softwood Ash

Abstract

In an attempt to convert agricultural residue to alternative binding material for use in construction industry, this research considered the use of wood ash from Anacardium- occidentale (kaju) wood which is softwood as a pozzolan in cement production. In this study, the chemical composition (silica (SiO.), aluminum oxide (AI,O,), ferric oxide (Fe,O,), calcium oxide (CaQ), magnesium oxide (MgO), sulphur trioxide (SO,), sodium oxide (Na,O) and potassium Oxide (K,O)) of the ashes and the clinker was investigated. The production of blended cements were carried out in the factory by replacing 5- 50% by weight of Ordinary Portland Cement Clinker with the ashes during the manufacturing process. The cement without wood ash serves as the control. The physical characteristic (fineness, initial and final setting times, heat of hydration and residue on 45um sieve), and the chemical composition of the blended cements were also investigated. The results showed that Anacardiumoccidentale ash (AOA) was a suitable material for use as pozzolan since it satisfied the requirement for such a material by having a combined SiO, Fe,O,and Al,O,of more than 70% according to ASTM C 618. The AOA blended cements satisfied standard requirements for up to 20% replacement level. It was concluded that the wood ash was suitable for use in the production of blended cements.