下水汚泥焼却灰を用いたコンクリートの凝結性状の改善に関する一検討

抄録

In recent years it tends to increase in the percentage of sewered population and increase in the generation rate of the sewage sludge every year. And weight reduction and effective utilization of sewage sludge and sewage sludge incinerated ash are desired more. In this research, authors aimed to use sewage sludge incinerated ash as admixture for concrete and make the influence to concrete clear. Sewage sludge incinerated ash has high ratio of restraining water, bad dispersibility by powder properties and the phosphorus included in the incinerated ash, make the setting of cement delayed. Therefore improvement of setting properties was measured by giving the condition to suggest reduction of setting time, and it was examined what kind of influence came to properties of setting and strength in mortar or concrete. To improve setting properties, authors used sewage sludge incinerated ash that was controlled the grading, limestone fine powder and accelerator, and to investigate the reason of delay on setting, the initial hydration temperature was measured. As a result, it was found that the use of limestone fine powder or accelerator enabled to reduce the setting time. This is because the promotion of initial hydration of alite by limestone fine powder or accelerator can reduce the setting time. So, authors found out that setting properties were influenced by C-S-H which makes promote initial hydration of alite. It's possible to use many sewage sludge incinerated ash as concrete materials by using these improvement methods, and we can think the utility value as the concrete material may generate.