INVESTIGATING THERMAL PROPERTIES OF SAWDUST ASH – CEMENT CONCRETE AS A POTENTIAL CONSTRUCTION MATERIAL

A. A. Raheem; K. O. Oriola; A. Ismail

A. A. Raheem Department of Civil Engineering, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
K. O. Oriola Department of Agricultural Engineering, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria
A. Ismail Department of Civil Engineering, Ladoke Akintola University of Technology, Ogbomoso, Oyo State, Nigeria

Keywords: Sawdust ash, Pozzolan, Workability, Thermal conductivity, Thermal diffusivity, Thermal resistivity, Specific heat capacity

Abstract

This study examined the thermal properties of concrete produced from partial replacement of the cement content with Sawdust Ash (SDA). Sawdust col¬lected from sawmill was burnt into ashes and analyzed for chemical composition (silica, alumina and iron oxide) using x-ray fluorescence analyzer. Concretes were produced by replacing 5 - 25% by weight of the cement with SDA. Slump and compacting factor tests were also carried out. A total of 72 concrete cubes (150 mm) were cast. Thermal conductivity (k), diffusivity (α) and specific heat capacity (Cp) of the cubes were determined at the ages of 7, 28, 56 and 90 days, using KD2 Pro thermal properties analyzer. The data obtained were analyzed with SPSS…. The percentages of silica, alumina and iron oxide obtained for SDA were 65.29%, 6.43% and 3.83%, respectively. The slump and compacting factor values ranged from 85 - 110 mm and 0.91 - 0.95 mm, respectively. k of the SDA concrete at 90 days at both room and elevated temperature decreased from 1.67 - 1.21 W/mK and 1.63 - 1.19 W/m3K, respectively. Values of α at room and elevated temperature increased from 0.36 - 0.49 mm2/s and 0.37 - 0.54 mm2/s, respectively while the Cp at both room and elevated temperatures decreased from 3.79 - 2.63 MJ/m3K and 3.19 - 2.18 MJ/m3K, respectively. Second order polynomial equation described the relationship between the thermal properties and curing age. Thermal diffusivity increased with temperature. SDA exhibits good insulating properties required for external walls, partition walls of building and farm structures.