Investigation on physical properties and compressive strength of gobi aggregate concrete
In order to make use of the gobi aggregate,the waste material excavated in the engineering construction in northwest China,it focused on the gobi aggregate of an airport expansion project in northwest China.Firstly,the basic physical properties and mineral components of gobi aggregates were analyzed,and then taking water cement ratio,gobi sand ratio,type of fine aggregate and amount of cementitious material as changing parameters,the working performance,failure mode and compressive strength of gobi aggregate concrete were studied successively.The results showed that gobi aggregates have a high mud content,and the clay minerals mainly contain smectite and illite with strong water absorption capacity about 20%.With the increased in water cement ratio,the slump decreased but the compressive strength increased linearly,which was consistent with the law of ordinary concrete.Under the same mix ratio,the compressive strength of all gobi aggregate concrete was higher than that of gobi coarse aggregate concrete,but the mixture of the former is more viscous.Although the slump of all gobi aggregate concrete could be slightly improved by screening out gobi fine aggregates with a particle size of less than 0.15 mm,the compressive strength was unfavorable.With the increase of gobi sand ratio,the compressive strength of concrete increased first and then decreased but the slump kept increasing.Finally,through regression analysis,suggestions on mix proportion design of gobi aggregate concrete were given.
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