再生骨料制备经济型RPC力学性能试验研究

Study on Mechanical Properties of Reactive Powder Concrete Prepared by Construction Waste

利用废旧混凝土生产的再生细骨料全部代替石英砂制备经济型活性粉末混凝土(RPC)。通过实验室试验及分析得到了各影响因素(集胶比、养生方式、钢纤维掺量、骨料粒径)对RPC力学性能的影响规律,并通过冻融循环试验测试了RPC的抗冻性能。试验结果表明,集胶比为1.5时,RPC抗压强度>80 MPa,抗折强度>14MPa;集胶比由1.5增加到3时,强度降低30%;与标准养生的RPC相比,蒸汽养生条件下的RPC的力学强度较高;掺入钢纤维可以显著提高RPC的抗折强度和劈裂抗拉强度,但是对抗压强度影响较小;50次冻融循环后,RPC抗压强度损失率为10%~20%,可在寒冷地区推广使用。本研究可为再生骨料制备经济型RPC的设计和施工提供参考依据。

The recycled fine aggregate produced from waste concrete is used to replace the quartz sand to prepare economical reactive powder concrete(RPC).The effects of various influencing factors(aggregate-cement ratio,curing method,steel fiber content,aggregate size)on the mechanical properties of RPC are obtained through laboratory tests and analysis.The freeze resistance of RPC is tested by freezethaw cycle test.The test results show that when the aggregate-cement ratio is 1.5,the RPC compressive strength is greater than 80 MPa,the flexural strength is greater than 14 MPa;when the aggregate-cement ratio is increased from 1.5 to 3,the strength is reduced by 30%;compared with the standard curing RPC,the mechanical strength of steam curing conditions RPC is higher;the incorporation of steel fiber can significantly improve the flexural strength and splitting tensile strength of RPC,but the impact on the compressive strength is small;the RPC compressive strength loss rate is 10%to 20% after 50 freeze-thaw cycles,and can be promoted and used in cold regions.It provides a reference for the design and construction of economical RPC using recycled aggregate.