Application of Bagasse Ash and Pozzolanic Material to Cement Mortar
Abstract
Cement is the most widely and frequently used building material today. However, it is manufactured by a highly-polluting and energy-consuming industry. Bagasse ash (BA) is the secondary waste product from bagasse-fired power generation. If BA could become a replacement for cement, it would greatly reduce environmental pollution and energy consumption as well as achieve waste recycling. This study tested the early and late compressive strength of cubic cement mortar specimens with various water-binder ratios and different proportions of cement replaced with BA, observed their specific gravity and water absorption rates at 28 days, and compared BA with fly ash (FA) and slag ash (SA) under identical conditions. In addition, we employed scanning electron microscopy (SEM) to measure surface microstructures and investigated the resulting differences in hydration behavior and pozzolanic reactions. The results revealed that even without any grinding process, the BA produced by the burning of bagasse that has been thoroughly rinsed already displays smaller particle sizes than commercially available cement and SA. This means that maintaining the cleanliness of the bagasse before burning it for power generation can save the costs of BA grinding or screening processes. The test results indicate that higher water-binder ratios with BA increase late-age strength, which proves that the pozzolanic reaction is the cause of this increase and that its reaction effects surpass those of FA and SA. Furthermore, BA is suitable for cement mortar mixtures with high water-binder ratios, and the optimal proportion of cement replaced with BA is proportional to the water-binder ratio; a higher water-binder ratio means that more cement can be replaced with BA. The C-S-H gel formed by the BA pozzolanic reaction displays a continuous and dense grid pattern. The BA pozzolanic reaction increases the density and strength of the porous structures in cement paste.
Keywords
Concrete, Bagasse ash, Pozzolan, Waste material
Publication Date
DOI
10.12783/dteees/peee2016/3873
10.12783/dteees/peee2016/3873
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