养护温度对水泥固化淤泥强度影响试验研究

Experimental investigation on effect of curing temperature on strength development of cement stabilized clay

采用水泥固化海泥(CSMC)作为围海垦地填料正在被广泛关注。由于水化放热,当环境温度较高时大体积填筑的CSMC内部实际养护温度可能明显高于室内标准养护温度(≈20℃),这必然会对CSMC的强度发展产生影响,但目前工程实践中并未考虑这一温度差异的影响。因此,基于室内试验,测试了不同配合比CSMC试样在不同养护温度下的强度发展过程,并重点探讨了养护温度对CSMC强度发展的影响规律及其内在机制。结果表明:养护温度对CSMC强度发展影响显著,高的养护温度不仅会显著提高CSMC的早期强度,而且会比较明显地提高CSMC的晚期强度,这就意味着在CSMC垦地工程实践中考虑养护温度的影响是十分必要的。鉴于此,文中最后给出了如何在CSMC垦地工程实践中考虑养护温度对强度发展影响的建议和设计流程。

The use of cement stabilized marine clay（CSMC） as a filling material for land reclamation has received increasing attention and popularity in recent years. In tropical or subtropical areas, the actual curing temperature in the field can be much higher than the standard curing temperature of 20 ℃ in a laboratory, owing to the autogenous heat generated from cement hydration within the large casting volume as well as the relatively higher ambient temperature. This curing temperature difference is not taken into account in current design practice. Therefore, a series of laboratory tests is first conducted to acquire strength development curves of CSMC samples with different mixing proportions and different curing temperatures, and the influencing mechanism of curing temperature on qu development is then studied. The results indicate that the curing temperature has a significant influence on qu gain. A higher curing temperature gives rise to not only a higher short-term strength, but also higher long-term / ultimate strengths. This finding suggests that it is of practical importance, particularly in land reclamation projects where the volume used is often very large, to consider the curing temperature effect on the strength gain of CSMC. As a consequence, a procedure accounting for the curing temperature effect in the design of CSMC mixing proportion is proposed lastly.