Proposal of Sustainable Recycle System of High Quality Recycled Aggregate with Blast-furnace Slag Cement

为建立矿渣水泥再生骨料的可持续再生体系，本文对如何提高矿渣水泥混凝土的抗裂性能进行了研究，主要研究结果如下：(1)研究了轻质细骨料对降低混凝土收缩、提高矿渣水泥混凝土抗裂性的有效性。(2)建立了利用声发射技术分析骨料周围微裂纹的方法。利用声发射技术对高温历史条件下的极早龄期混凝土进行了研究。阐明了微裂缝的产生机理，并对微裂缝的特性进行了详细的研究。(3)建立了含声发射的体外约束混凝土微裂缝分析方法。约束试件的抗裂强度远低于未约束试件的抗拉强度。并用声发射分析对其原因进行了分析。

In this research, in order to contribute to sustainable recycle system of high quality recycled aggregate with blast-furnace slag cement, how to improve crack resistance of slag cement concrete was investigated.The main results of this study are as shown below.(1) The effectiveness of the use of lightweight fine aggregate to reduce shrinkage of concrete and to improve crack resistance of slag cement concrete was exhibited.(2) The method to analyze microcrack around aggregate with Acoustic Emission Method was established. AE technique was utilized for very early age concrete under high temperature history. The mechanism of the generation of microcracking was clarified and the properties of microcracking were examined in detail.(3) The method to analyze microcrack of externally restrained concrete with AE was developed. The cracking strength of restrained specimens was much lower than the tensile strength of unrestrained specimens. The reason was investigated with AE analysis.