| The tailings sand and PVA fiber reinforced tailings cementitious composite used large quantity of tailings sand and fly ash to instead of fine aggregate and cement aimed to save resource and improve the performance,which made ECC preparation technology for reference,to explore the fiber reinforced tailings cementitious composite with environmentally friendly high performance.The team had done much mechanical properties experiments,which showed that the material had good mechanical properties and engineering application prospect.However,the research on the durability of the material was less,therefore,this paper proved its preparation technology on the basis of previous work,and the durability such as frost resistance,permeability resistance,carbonation resistance,corrosion resistance performance were studied,the effect of PVA fiber volume ratio and water-binder ratio on the durability of the tailings sand and PVA fiber reinforced tailings cementitious composite was studied from the perspective of mixture ratio of the composite which provided certain scientific basis for the development and application of tailings sand and the application of the cement-based composite materials in engineering.The main content and main conclusions of the paper were as follows:(1)Through the study of the selection of raw materials,mixing ratio and mixing system,the preparation of the tailings sand PVA cement-based composite raw materials,the ratio of key materials and reasonable mixing system were determined.(2)Quality loss and compressive strength loss of the tailings sand and PVA fiber reinforced tailings cementitious composite under different freezing and thawing cycle times was studied through laboratory freeze-thaw test,the results showed that the anti-frost property of the composite with PVA fiber was superior to those without PVA fiber,the optimal volume of fiber content was given,the anti-frost property of the composite gradually decreased as the water cement ratio increased.(3)The impervious capacity of the cementitious composite combined with tailings mortar and PVA fiber under 1.2 MPa constant water pressure was studied by the test of water penetration height,the results showed that adding a certain volume of fiber could improve the permeability properties of the cementitious composite combined with tailings mortar,but when the content of the fiber reached to a certain degree,the permeability resistance of the material decreased instead,the permeability resistance of the material decreased as the water cement ratio increased.(4)The carbonation resistance performance of the tailings sand and PVA fiber reinforced tailings cementitious composite was studied through the rapid carbonization test,the results showed that natural carbonation would not reach the surface of the steel bar in the structure design working life for the tailings sand and PVA fiber fiber reinforced tailings cementitious composite when the replacement rate of the tailings sand was 50%,the carbonation resistance performance of the cementitious composite combined with tailings mortar and PVA fiber could be effectively improved by adding a certain volume of fiber,the carbonation resistance performance decreased gradually as the water cement ratio increased.(5)The corrosion resistance performance of the tailings sand and PVA fiber reinforced tailings cementitious composite was studied through sulfate dry-wet circulation and wet cycle corrosion tests,the results showed that the corrosion damage speed of the tailings sand and PVA fiber reinforced tailings cementitious composite in the dry-wet circulation environment was faster than in the wet circulation environment,a certain volume of fiber was added in the dry-wet circulation environment to improve sulfate corrosion resistance performance of the tailings cementitious composite effectively,the optimal fiber volume content was given,the sulfate corrosion resistance performance of the material decreased as the water cement ratio increased. |
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