摘要
以3种煤矸石取代骨料的方式配置低强度混凝土,研究了煤矸石掺量、类型对低强度混凝土坍落度、力学强度等性能的影响规律,并采用岩石点荷载测试和光学显微镜、扫描电镜等方法分析了煤矸石作为骨料对低强度混凝土强度的影响机理。结果表明:煤矸石对低强混凝土的强度影响不仅与取代方式有关,同时也取决于煤矸石的种类;煤矸石取代间断级配粗骨料30%以上时,混凝土抗压强度最大降低为24.9%;煤矸石全取代粗细骨料,混凝土强度会降低40%~60%;在煤矸石已取代连续粗骨料的前提下若继续取代细骨料,抗压强度会继续下降27%,劈裂抗拉强度会下降24.1%。煤矸石对低强度混凝土的强度降低效应主要是自身强度低以及界面过渡区(煤矸石-水泥)薄弱;为缓解因煤矸石取代所造成的强度"弱"化,可适当通过掺入粉煤灰的方法来改善。
The authors replaced the aggregate with coal gangue in three different ways and studied the effect law of the amount and the type of coal gangue in slump and mechanical strength of low-strength concrete.Furthermore,the influence mechanism on the strength of lowstrength concrete with coal gangue as aggregate was analyzed by rock point load testoptical microscope and scanning electron microscopy.The results show that the influence of coal gangue on the strength of low-strength concrete is not only related to the way of substitution,but also depends on the kind of coal gangue.When coal gangue replaces discontinuous grade with coarse aggregate more than 30%,the concrete compressive strength will be reduced by 24.9%.When coal gangue replaces coarse and fine aggregate completely,the strength of the concrete will be reduced by 40%~60%.Under the coal gangue replacing the continuous coarse aggregate if the coal gangue replace the continuous fine aggregate,the compressive strength will continue to decrease by 27%and the splitting tensile strength will decrease by 24.1%.The effect of coal gangue on the strength reduction of low-strength concrete is mainly due to its low strength and weak interface transition zone(gangue-cement).Adding fly ash can alleviate the"weakness"of the strength induced by the replacement of coal gangue.
作者
白朝能
李霖皓
沈远
龙广成
马昆林
BAI Chaoneng;LI Linhao;SHENG Yuan;LONG Guangcheng;MA Kunlin(Xi’an Railway Survey and Design Institute Co.,Ltd.,Xi’an 710054,China;School of Civil Engineering,Central South University,Changsha 410075,China)
出处
《煤炭科学技术》
CAS
CSCD
北大核心
2020年第S01期270-277,共8页
Coal Science and Technology
基金
中铁西安勘察设计研究院有限责任公司2017年科技计划资助项目(738010875).
关键词
煤矸石
低强度混凝土
粉煤灰
取代方式
coal gangue
low-strength concrete
fly ash
replacement method
