Research On Influential Factors Of Abrasion Resistance Of Pavement Manufactured Sand Concrete

With the vigorous development of our infrastructure, expanding proportion of highway construction of total, strengthening consciousness of social energy saving and environmental protection and shortage of nature sand resource, manufactured sand used in pavement concrete is imperative.Compared with nature sand, MS (manufactured sand) is characteristic of rough particle and angular, with a large amount of stone dust and lithofacies diversity. Research the characteristics of MS on abrasion resistance is largely beneficial for the application of MS on pavement concrete.Aiming at the characteristics of MS and the mixture design parameters, investigated the effects of water to cement ratio, sand ratio, fineness modulus, stone dust content in MS and Los Angeles abrasion as well as parent rock kinds of MS on the strengths and abrasion resistance of pavement concretes. Results show that with the decrease of water to cement ratio, the strength and abrasion resistance of manufactured sand concrete were improved, and the MS with larger fineness modulus and suitable lower sand ratio were beneficial to the abrasion resistance of pavement concrete; The increment of stone dust from 4.3 to 20% did not adversely affect the strength, and the abrasion loss of concretes was reduced. The abrasion resistance of the manufactured sand concrete had not evident relation with the silicon content of sand, while comparatively better relation with Los Angeles, surface roughness and crushing index of sand particles.Based on gray system theory, the relationship degree among complications on abrasion resistance of MS concrete were calculated, the conclusion shows that the most important factor effect the abrasion resistance of pavement MS concrete is the content of stone dust in MS. In order to obtain the higher performance abrasion resistance MS concrete, it is necessary to have higher content of stone dust to make sure the density of concrete.Combining with the mechanism of stone dust in concrete, preliminary discussed the abrasion resistance mechanism of MS pavement concrete. In the abrasion process of MS concrete, porosity, interface, aggregates and matrix are the basic four factors effect the abrasion resistance. The abrasion resistance of concrete can be guaranteed by appropriate adjustment of parameters and control of indicators as well as the characteristics of sand which improve the pore structure and interface structure of MS concrete.According to the classical high packing theory, the idea of super-filling system in concrete was put forward; set K1 as the margin coefficient of paste and K2 as the margin coefficient of mortar, regarded stone dust as paste to carry out a mix design; explored a feasible and applicable mix design method of pavement MS concrete.