非自燃煤矸石粗骨料对混凝土力学性能的影响

Effect of coarse aggregate of non-spontaneous combustion coal gangue on mechanical properties of concrete

非自燃煤矸石是煤炭开挖和分选等过程中产生的固体废弃物,为减少大量非自燃煤矸石堆积而造成的环境污染、资源浪费以及对天然砂石资源的过度利用,研究非自燃煤矸石的理化性能以及在不同粗骨料取代率、水灰比、附加用水量和骨料级配下的非自燃煤矸石混凝土基本力学性能.结果表明:与普通碎石相比,非自燃煤矸石的堆积密度与表观密度小、吸水率高、压碎值大.水灰比和非自燃煤矸石取代率对非自燃煤矸石混凝土坍落度的影响较为明显,随着非自燃煤矸石取代率和水灰比的增大,混凝土的抗压强度、抗拉强度和弹性模量总体上逐渐减小,当取代率超过50%时,以上指标减小较为明显.附加用水量和骨料级配对非自燃煤矸石混凝土力学性能有一定的影响,饱和面干状态下的非自燃煤矸石粗骨料可以有效提高混凝土的抗压强度和弹性模量,但对抗拉强度不利.建议实际工程中非自燃煤矸石取代率小于50%,且当非自燃煤矸石取代率为50%、水灰质量比为0.35时,混凝土强度可以满足C40的设计要求.

Non-spontaneous combustion coal gangue is a solid waste produced in the process of coal excavation and sorting.In order to reduce environmental pollution and resource waste caused by the accumulation of non-spontaneous combustion coal gangue and reducing the overuse of natural sand resources.In this work,the physical and chemical properties and the basic mechanical properties of non-spontaneous combustion coal gangue concrete under different coarse aggregate replacement rate,water-cement ratio,additional water consumption and aggregate gradation were studied.The results show that the bulk density and apparent density of non-spontaneous combustion coal gangue are smaller,water absorption is higher and crushing value is larger than that of ordinary gravel.The water-cement ratio and the replacement rate have significant effects on the slump of non-spontaneous combustion coal gangue concrete.The compressive strength,tensile strength and elastic modulus of concrete decrease gradually with the increase of non-spontaneous combustion coal gangue replacement rate and water-cement ratio.When the replacement rate is more than 50%,the above indexes decrease obviously.The additional water consumption and aggregate grade have a certain effect on the non-spontaneous combustion coal gangue concrete.