自燃煤矸石骨料含水状态对混凝土性能的影响

Effect of Moisture State for Spontaneous Combustion Gangue Aggregate on Concrete Performance

自燃煤矸石骨料具有孔隙率大、吸水率高的特点,使其含水状态对混凝土性能的影响程度远大于天然骨料。利用气干、湿润和饱和面干状态的自燃煤矸石骨料配制备混凝土,通过混凝土稠度和强度试验,揭示自燃煤矸石骨料含水状态对混凝土性能的影响。结果表明,按普通混凝土设计方法确定单位用水量,气干状态自燃煤矸石骨料配制的混凝土,拌合物干稠不能满足大流动预拌混凝土施工要求,加强振捣后硬化混凝土强度比普通混凝土高两个等级;按轻骨料混凝土设计方法确定单位用水量,即饱和面干自燃煤矸石骨料配制的混凝土,拌合物出现泌水、离析现象,强度降低一个等级;当自燃煤矸砂掺入吸水率60%的附加水、自燃煤矸石掺入吸水率80%的附加水,且提前1 h润湿,配制的混凝土流动性和抗压强度与普通混凝土相当。

Because of spontaneous combustion gangue aggregate have some characteristics, for example, large porosity, high bibulous rate, so the effect degree of moisture state for spontaneous combustion gangue aggregate on concrete performance is greater than natural aggregate. This paper, using gas dry, wet and saturated surface dry state of spontaneous combustion coal gangue aggregate to prepare concrete, through the concrete consistency and strength test to reveal the effect of moisture state for spontaneous combustion gangue aggregate on concrete performance. The results show that according to the ordinary concrete design method to determine the unit water use, the dry condensed state of the concrete mixture which was prepared by using gas dry state of spontaneous combustion coal gangue aggregate cannot meet the construction requirements. When the concrete was strengthened vibratory, the strength of hardened concrete had improved two levels higher than ordinary concrete. According to the lightweight aggregate concrete design method to determine the unit water use, that is to prepare concrete by using saturated surface dry state of spontaneous combustion coal gangue aggregate, the concrete mixture appeared bleeding, segregation phenomenon, and the strength had decreased a level. In addition that, when the spontaneous combustion coal gangue sand mixed with an additional water which was 60% of water absorption, the spontaneous combustion coal gangue mixed with an additional water which was 80% of water absorption, and both of the two aggregates were wetted 1 h in advance, the mobility and compressive strength of the concrete which was prepared with them were equal to that of ordinary concrete.