A Study on Municipal Solid Waste Incinerator Bottom Ashes Used as Fine/Coarse Aggregates of Concrete Block

• Main Authors: Po-Ting Chen, 陳柏廷
• Other Authors: Ming-Sheng Ko
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/sh7z8q

碩士 === 國立臺北科技大學 === 資源工程研究所 === 101 === In this study, the feasibility of MSWI bottom ashes fully substituting for natural sandy gravels as fine/coarse aggregates to produce concrete block is evaluated, and the experimental parameters such as water-cement ratio, coarse aggregate ratio , cement ratio, slag added ratio and stirring time are investigated. The experimental molding machine was used to produce concrete block specimens and the compressive strength test of concrete block is performed after 28 days of curing at room temperature. The types of aggregate are including natural sandy gravel and MSWI bottom ash. The ratio of water to cement is set to 0.22, 0.26 and 0.3 . The ratio of coarse aggregate is set to 0%, 15% and 30%, and the ratio of cement is set to 0.15, 0.2 and 0.25. In addition, the ratio of slag added is set to 0%, 15% and 30%, and the slurry mixing time is set to 2 minutes, 3minutes and 4minutes. All operating parameters were designed with Taguchi methods. By analyzing the engineering properties of concrete blocks such as compressive strength, water absorption, porosity and unit weight, it explored the feasibility of concrete blocks made from MSWI bottom ash aggregate. The results indicated that the optimum experimental parameters were 0.3 of water-cement ratio, 30% of coarse aggregate ratio, 0.25 of cement ratio, 0% of slag added ratio and 3 minutes of slurry mixing time. The highest compressive strength of all specimens would reach to 250kgf/cm2, it was close to the standards of CNS 3930. However under lower water-cement ratio, the compressive strength of concrete block made from natural sandy gravel aggregate was not significantly better than MSWI bottom ash. Based on the above results, the following experimental parameters such as cement ratio, coarse aggregate ratio and slag added ratio would be further investigated. By analyzing unit weight, porosity, water absorption and compressive strength of concrete blocks, the optimum parameters were 0.3 of cement ratio, 40% of coarse aggregate ratio and 4% of slag added. The highest compressive strength of concrete blocks would reach to 300kgf/cm2, it complied with the standards of CNS 3930. Besides, the effects of weather resistance through wet-dry cycle test is evaluated, the results indicate that the higher compressive strength of concrete block is, the more wet-dry test cycle is. Based on the results of this study, it is feasible that MSWI bottom ashes could fully substitute for natural sandy gravels as fine/coarse aggregates to produce concrete blocks.