細粒料與強塑劑含量對輕質骨材混凝土影響之研究

摘要　　由於天然砂石匱乏，人造砂石研發更顯得重要，人造輕質骨材會依原料及地域性差異而有不同的的特性，輕質骨材混凝土具有減輕混凝土結構物自重、隔熱性佳、耐火性高等優點，對於低密度之輕質骨材於拌和混凝土時為了避免輕質骨材產生浮起或析離，因此均採低坍度低工作性拌和。　　細骨材率（S/a）為細粒料體積佔總粒料體積之百分比，會改變輕質骨材混凝土之單位重，並間接影響輕質骨材混凝土的強度，強塑劑可增加水泥漿體的流動性進而影響混凝土之工作性質，本研究目的是探討在不同細骨材率與強塑劑添加量下輕質混凝土之性質，以改善輕質骨材混凝土之工作性且達到穩定強度的發展。　　研究結果發現，當細骨材率（s/a）愈高時單位重愈大強度會愈高；強塑劑添加量愈高時輕質骨材混凝土流動性越佳，易產生粗粒料浮起現象，添加強塑劑提高流動性使輕質骨材混凝土更緻密，但採用天然砂為拌和細粒料，會造成輕質骨材混凝土之熱傳導係數提高，降低隔熱性質。

關鍵字

細骨材率；輕質骨材混凝土；熱傳導係數；強塑劑

並列摘要

ABSTRACT 　　In the future, it is certain that natural aggregates used to mix concrete will be deficient. Therefore, the study of artificial aggregate will become more important. Properties of artificial lightweight aggregate are different depending on raw materials and manufacture process. Lightweight aggregate concrete has the advantages of smaller dead load of the structure, better fire-resistant and heat insulation. However, low slump and workability are usually adopted for lightweight concrete due to the low density of the aggregates and to avoid segregations. 　　The dead weight and strength of lightweight concrete depends on the s/a factor, which is the percentage of fine aggregate to total aggregate by volume. It could change. The use of superplasticizer will increase the fluidity and workability of fresh concrete. In this research, different proportions of fine aggregate and superplasticizer are used in order to study their effect on the workability and strength of lightweight aggregate. 　　Experiment results show that the dead weight and strength of lightweight concrete are both increased with the increasing use of fine aggregates. Increase in the use of superplasticizer will increase the fluidity and workability of lightweight concrete. However, excess in superplasticizer will cause segregation of fresh concrete, resulting in the rising of lightweight aggregates. In this research, since natural fine aggregate is used, the coefficient of thermo-conductivity is similar to that of normal weight concrete.