Practical Application of Structural Super Lightweight Aggregate Concrete

最近，日本开发出了超轻质人工骨料。比重在0.8~1.2左右，吸水率小于3.0%。其抗压强度是传统人工骨料的两倍多。本研究对这种结构超轻混凝土的实际应用进行了研究，在试验的基础上，研究了结构超轻混凝土的断裂性能以及配筋和预应力超轻混凝土梁的抗剪性能。作为这项研究的结果，获得了以下发现。(1)在抗压强度相同的情况下，SLC混凝土的断裂能远低于普通骨料混凝土。SLC梁的抗剪承载力也呈现出相同的变化趋势。(2)SLC抗压强度的提高并不能显著提高断裂能。(3)为了提高抗剪能力，掺入短纤维，S…更多的如聚乙烯醇短纤维，在材料方面是非常有效的。预应力的使用对提高SLC梁的抗剪能力也是非常有效的。作为第二步，尝试了两种措施来提高SLC梁的抗剪能力。第一个是故意降低SLC梁的抗压强度，另一个是超轻集料与普通集料的混合使用，如碎石。通过研究工作证实，无论超轻集料的比重如何，这两种方法都是相当有效的。最后，针对SLC的实际应用，对SLC组合梁进行了试算设计。并利用计算机图形学进行了美学评价。从试验设计来看，SLC组合梁可以将上部结构的自重降低到普通PC梁的近50%。SLC可以提供细长、智能的混凝土结构。较少

Recently, super lightweight artificial aggregates have been developed in Japan. The specific gravity is around 0.8 to 1.2, and the absorption ratio is less than 3.0%. The compressive strength is more than double of conventional artificial aggregates. In this research, the practical application of this structural super lightweight concrete (SLC) has been investigated.As the first step of this research work, fracture properties of SLC, and shear resisting capacities of reinforced and prestressed SLC beams have been investigated based on the experiments. As the result of this study, the following findings have been obtained. (1) The fracture energy of SLC is much lower than normal aggregate concrete having the same compressive strength level. The shear capacity of SLC beams also shows the same tendency. (2) The increase in the compressive strength of SLC does not provide the significant increase in the fracture energy. (3) To improve the shear resisting capacity, the mix of short fiber, s … More uch as polyvinyl alcohol short fiber, is very effective in the material viewpoint. The use of prestressing is also very effective to improve the shear capacity of SLC beams.As the second step, two countermeasures have been tried to improve the shear capacity of SLC beams. The first one is the intentional decrease in the compressive strength of SLC beams, and another one is the mixed use of super lightweight aggregates with normal aggregates, such as crushed stone. After the research work, it is confirmed that these two methods are quite effective regardless of the specific gravity of super lightweight aggregates. Finally, for the practical application of SLC, the trial design of SLC composite girders has been carried out. The aesthetic evaluation by using the computer graphics is also performed. From the trial design, SLC composite girders can reduce the dead weight of super structures to almost 50% of the conventional PC girders. SLC can provide the slender and smart concrete structures. Less