| Summary: | 碩士 === 國立聯合大學 === 土木與防災工程學系碩士班 === 96 === How to treat the municipal solid waste has been a worldwide problem. In Taiwan the municipal solid waste was mainly burned to ash with incinerator, but the MSWI fly and scrubber ash contained large amount of heavy metals, which need to be treated to become harmless and recycled as useful resources. First, we try to mix fly-ash and scrubber-ash uniformly with the weight ratio of 1:3, the production ratio of the incinerator, and the waste glass powder was added to adjust the mix-ash basicity S (S = CaO/SiO2) from 0.8 to 1.2, and melted into slag and pulverized to powder with particle size less than Sleeve No.400 (38�慆). The pulverized slag powder was used to replace 20 wt.�s of cement for molding 5cm�e5cm�e5cm slag-blended cement mortar specimen for compressive strength test, the test result show that the compressive strengths of slag cement mortar specimens were weaker than those of plain cement mortar specimens before 28-day curing age, but those with curing ages of 60-day to 90-day were stronger than plain cement mortar specimen. Second, we selected slag powder with basicity S = 1.1 to replace 0�{40 wt.�s cement, and molded 5cm�e5cm�e5cm specimens for compressive strength test. The result revealed similar phenomenon, and the strengths of all specimens with 90-day curing age were still stronger than that of plain cement mortar specimen even the slag powder replacement was up to 40 wt.�s.
According to the good results of strength for slag cement mortar, we use the modified slag powder with basicitys S = 1.1 to replace 20 wt.�s cement and select three kinds of water to binder ratios (W/B = 0.68, 0.58 and 0.48) for molding slag cement concrete cylinder (10cmψ�e20cm H) specimens. Then they were under compressive strength test, stress-strain measurement, expansion measurement and durability test. The results revealed those the strength of the slag cement concrete specimens was weaker than that of plain cement concrete specimen at the early curing age, but they were similar at age of 28-day, and were stronger than those of plain cement concrete specimens with curing ages of 60-day, 90-day and 180-day. It seems like Pozzolanic reaction.
As aforementioned, the test results revealed that the modified MSWI mix-ash slag powder for partial cement replacement for concrete engineering is feasible in practical application. The treated fly and scrubber ashes are harmless and can be recycling as a resource and are good for sustainable environment of earth.
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