Browsing by Author "Amadi, Stanley Ogadinma"

Now showing 1 - 1 of 1
  • No Thumbnail Available
    ItemOpen Access
    Investigation of flexural strength of concretes containing rice husk and saw dust ashes from different calcination methods
    (Federal University of Technology, Owerri, 2016-07) Amadi, Stanley Ogadinma
    This work investigated the flexural strengths of concretes containing rice husk ash (RHA) and saw dust ash (SDA) from different calcination methods. RHA and SDA were produced using three different calcination methods namely, Open-Air (OA), Furnace (F), and Stove (S). Each of RHA and SDA was used as partial replacement of Ordinary Portland Cement (OPC) at 5%, 10% and 15%. 171 concrete beams of dimensions 150 x 150 x 600mm were produced using 1:2:4 cement–sand–sandstone mix ratio and 0.6 water/cement ratio. This comprised 81 OPC– RHA, 81 OPC–SDA and 9 OPC (control) concrete beams. The beams were cured by immersion and tested for flexural strengths at 28, 90 and 150 days. The results showed that the flexural strength of the blended cement concrete increased with curing age and decreased with increased amount of RHA and SDA. The 150th day flexural strengths for 5% RHA were 5.35 Nmm-2 for OA, 6.74 Nmm-2 for F and 5.20 Nmm-2 for S. Corresponding strengths at 5% SDA were 4.48 Nmm-2 for OA, 5.85 Nmm-2 for F, and 4.28 Nmm-2 for S, while the Control value was 6.41 Nmm-2 . Thus, for 5% replacement of OPC with RHA, OA calcination had 83.5% the strength of the control; F calcination had 105.1% the strength of the control, while S calcination had 81.1% the strength of the control. Similarly, for 5% replacement of OPC with SDA, OA calcination had 69.7% the strength of the control; F calcination had 91.3% the strength of the control, while S calcination had 66.7% the strength of the control. Therefore, although furnace calcination gave higher strength than open-air and stove calcinations, the latter two could still be used for structural members with lower flexural strength.