Study on the effect of water rust aggregate on concrete performance
In order to study the influence and explore the reasonable range of application of water rust gravel in concrete,the effects of 20%,40%and 60%mixtures on compressive strength,flexural strength,electric flux,relative dynamic modulus and mass loss of C30 concrete were studied respectively.The appearance morphology of water rust surface and normal surface of gravel,and the interface changes between water rust surface,normal surface and mortar in concrete before and after freezing and thawing were observed by scanning electron microscope.The results show that the compressive strength,flexural strength and relative dynamic modulus of concrete decrease,and the electrical flux and freeze-thaw cycle mass loss increase with the increase of the content of water rust particles in the coarse aggregate.Among them,the flexural strength,electric flux and relative dynamic modulus change significantly.Under the same dosage,the influence of double-sided rusted gravel on concrete performance is greater than that of single-sided rusted gravel.SEM test shows that the surface of gravel rust surface is loose,and there are fine cracks between the rust surface and mortar before freezing-thawing,but the cracks become more obvious after freezing-thawing cycle.From the test results,when there is frost resistance requirements,it is reasonable to control the content of double-sided rust particles within 25%,when the content of single-sided rust particles exceeds 60%,it will have a significant impact on the performance of concrete.
water rust coarse aggregatecompressive strengthflexural strengthelectric fluxrelative dynamic modulus
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