再生骨料高强高性能混凝土配制研究

通过对不同强度等级旧混凝土破碎而成的再生粗骨料与天然粗骨料性能的对比研究 ,表明再生粗骨料与天然粗骨料性能具有相似性 ,能够满足行业标准对碎石的性能要求 ,并尝试将再生粗骨料用于配制高强混凝土和自流平高性能混凝土 ,结果表明 ,采用原强度在 15～ 2 0MPa以上的旧混凝土破碎而成的再生骨料均可用于配制高强混凝土 ,但在配合比相近情况下 ,原混凝土强度等级越高 ,再生混凝土各龄期强度越高 ,其再生利用价值也越高。再生粗骨料亦可用于配制自流平高性能混凝土 ,水胶比为 0 4 0 ,净用水量为 2 0 5kg m3左右时 ,配制得到的新拌混凝土坍落度和坍落扩展度分别在 2 4 5、5 6 0mm以上 ,其 2 8、6 0d强度分别在 5 8 0、6 7 3MPa以上

RESEARCH ON HIGH STRENGTH HIGH PERFORMANCE CONCRETE MADE WITH RECYCLED CONCRETE AGGREGATE

By comparison between recycled concrete coarse aggregates crushed from different strength grade of original concrete and natural coarse aggregate,it is implied that the recycled and natural coarse aggregates have in fact similar properties and the recycled coarse aggregate can satisfy the aggregate requirements used for concrete.Then the recycled aggregates were tried to mix high strength concrete and self|compact high performance concrete.The results showed that even recycled coarse aggregate crushed from low strength concrete such as 15～20MPa can be used to produce high strength concrete,and compressive strength of recycled concrete at various ages increases with an increase in original concrete strength,on condition that the mixes designation are nearly the same,which implies the higher recycling value of higher strength concrete.Furthermore,the recycled concrete aggregate can also be used to mix self|compact high performance concrete,the slump and the slump spread of fresh concrete were over 245 mm and 560 mm respectively,the compressive strength at 28 days and 60 days were over 58^0MPa and 67^3MPa respectively,when the water/cement ratio was 0^40 and water content about 205kg/m+3.