降低自充填混凝土收縮之研究

Abstract

由於自充填混凝土於配比設計時，強調工作性及粒料不得析離沉澱，在漿體方面以低水粉比、添加強塑劑、添加卜作嵐材料等膠結材料之方向設計，單位體積的膠結材料較多；粒料方面則強調高細粒料含量及粗粒料最大粒徑較小，因此造成自充填混凝土比普通混凝土有較高的收縮量。為了減緩此一現象的發生，近來即陸續有研究提出許多外加摻劑，以減少自充填混凝土之收縮。 本研究係採用兩種無收縮材料：膨脹劑（Expansion agent）及減縮劑（Shrinkage Reducing Agent），探討其對於SCC之減縮效果及力學性質之影響。兩種材料皆於混凝土拌合時添加。藉由量測水分重量損失、體積收縮、耐久性及力學性質等，以探討研製無收縮自充填混凝土之可能。

The mix design of self-compacting concrete (SCC) emphasizes the workability and segregation resistance. In order to reach the target low w/b, higher fine aggregate, smaller and less coarse aggregate, and superplasticizer are general required. This characteristics results in higher shrinkage for SCC compared to conventional concrete. Measures were proposed to alleviate this phenomenon. This study used two types of admixtures for this purpose. One is expansion agent and the other is shrinkage reducing agent. The effects of these admixtures on the weight loss, volume stability, durability, and mechanical properties were studied.