稻殼灰-飛灰高性能混凝土蒸汽養護效能研究

Abstract

本研究針對高流動性 ( 坍度＝250±20mm、流度≒600mm )之稻殼灰 －飛灰高性能混凝土( Rice Husk Ash－Fly Ash High Performance Concrete，R-F HPC )，探討其早強及後續強度發展之特性，並對蒸汽養 護之效能加以分析，以期了解R-F HPC添加稻殼灰之早強及其他效能，並 探求R-F HPC蒸汽養護最適溫度和養護時間。 研究結果顯示：在一般 養護時，添加稻殼灰能提高R-F HPC早期(1 天)強度，而3天以後強度無明 顯提昇，且對乾縮及耐高溫性無明顯貢獻 ，但經蒸汽養護後，添加稻殼 灰之早強效能不如預期的好。在R-F HPC蒸汽養護最佳化方面，蒸汽養護 前須有適當之預置期，過早給予蒸汽養護對強度發展有不良影響，而較高 之蒸汽養護溫度可提高早期強度，但晚期強度會較低。R-F HPC 之凝結時 間較一般混凝土長，且坍度損失也較大 ，重複加劑可恢復原有之工作性 ，且對強度發展不致有不良影響。 關鍵字：稻殼灰-飛灰高性能混凝土、 蒸汽養護、乾縮。 In this study, the characteristics of the Rice Husk Ash - Fly Ash HighPerformance Concrete( R-F HPC) with high workability and flowability (Slump:250±20mm,Flow: 600mm) and its development of early and later strength wereexplored. Besides, the effect of steam curing was analyzed to get the earlystrength ofR-F HPC and its other effects after adding Rice Husk Ash to it. Moreover,the most proper temperature and period of steam curing for R-F HPC was also explored. The result showed that the adding of Rice Husk Ash could increase the one-day strength of R-F HPC with ordinary curing.However,after three daystedstrength had not increased obviously. The adding of Rice Husk Ash does not help to reduce the dry shrinkage and enhance the quality of resisting hightemperature. However, the benefit of early strength of the concretedue to the adding of Rice Husk Ash was not as good as expected after steam curing. As for how to get the best effect of steam curing o f R-F HPC, aproper period of preparedness was needed before steam curing. Applying steam curingtoo of early would be a bad influence on the development of strength.A highertemperature of steam curing could increase its strength at the early stage, butits strength would be weaker than that with lower temperature at thelate stage. Besides, the setting time of R-F HPC waslonger than that of ordinaryconcrete, and the loss of slump was greater,too. However, the addng of superplasticizers could recover the originalworkability and it would not have a bad influence on the development ofstrength. Key Words：Rice Husk Ash-Fly Ash High Performance Concrete ;Steam Curing Dry Shrinkage