Bottom ash effect in portland cement composite performance

Abstract

The main goal of this study was to investigate the effectiveness of bottom ash in Portland cement in improving the cement properties. The insufficient of published literature regarding to replacement of bottom ash into Portland cement create meticulous investigations in order to use widely through technically viable for highly performance of cement in construction industry. Three types of particle sizes (63, 75, 150 μm) and effect of using various weight percentage of bottom ash were investigated. The bottom ash cement composite were prepared with the same water to cement ratio (0.5) where the replacement of cement to bottom ash was 10, 20, 30, and 40 wt%. The compressive strength result of bottom ash cement composite was encouraging after 1, 7, 14, 28, 60, 90, and 360 days of curing (20.44 to 36.79 MPa). The mechanical analysis result shows that samples containing bottom ash may achieve the compressive strength that are very close to the performance presented by Portland cement. Furthermore, it was observed that the greatest combination of bottom ash was 10 % replacement. The replacement of bottom ash does not affect the strength properties as the strength still remains within the ASTM C270 limit. The optimum pozzolanic activity index result (63 μm with 10 % BA replacement) shows excellent performance that close to 0.94 on the 28th day and reaching 0.96 at 90th day which indicated that bottom ash is a pozzolanic material with high pozzolanic activity. Material properties such as morphology, mineralogical, chemical compound, and ternary phase diagram are explored which provide strong evidence and fundamental explanation to this research findings. The optimum replacement ratio of bottom ash (63 μm with 10 % BA replacement) was used to determine its application in acid and fire resistance. The major factors that causing chemical and physical attack are mechanism of chemical transport and temperature. Evaluation of acid and fire resistance of bottom ash cement composite was as important as mechanical testing where external hydrochloric acid and thermal fire properties were examined by performing the laboratory test. The results of acid resistance indicated that bottom ash cement composite have better resistance towards hydrochloric acid as compared to Portland cement. The performance of fire resistance of bottom ash cement composite under 600 °C have almost identical result as control Portland cement whereas result of 1200 °C shows reduction in compressive strength. The productive use of bottom ash is the best way to solve the problems associated with its disposal by solving landfill problem.