Research On Preparation And Road Performance Of Machine-made Sand Roller Compacted Concrete

Roller compacted concrete(RCC)is a kind of dry and hard concrete with high compactness.Compared with ordinary cement concrete,its main advantages are fast construction,large amount of saving cement and less water consumption.Roller compacted concrete pavement is generally paved with asphalt pavement construction machinery to pave,roll forming.In the production process of machine-made sand,a large number of stone powder will inevitably be produced.However,there are stringent requirements for the content of stone powder in machine-made sand in road engineering in China.Too much stone powder is washed and accumulated into mountains,which not only wastes resources,but also destroys the environment.In the existing research,the influence of stone powder content on the road performance of RCC has not been studied,but in the water conservancy project,it has been studied and put forward that a higher stone powder content is conducive to improving the performance of RCC dam.Therefore,based on the principle of economy and practicability,this study analyzed the influence of the content of stone powder in manufactured sand from Panlong gravel site in Guangxi on the road performance of RCC.(1)Firstly,the paper gives the principle and technical index of raw materials used in the preparation of RCC,then makes the preliminary design of mix proportion through the empirical method,and then adjusts the water-cement ratio at the maximum dry density and the best moisture content through the geotechnical compaction test as the final mix proportion,because fly ash can replace cement in the current RCC pavement because it can improve the strength of concrete.For the most common practice at this stage,and ordinary concrete can meet the design requirements in 28 d,this paper chooses two groups of mix proportion of fly ash RCC with similar mechanical strength of 28 d without fly ash to study the influence of stone powder content.(2)In the fourth chapter,the compressive strength and splitting strength of RCC with 0%,5%,10%,15% and 20% stone powder content are studied.It is found that when stone powder content is less than 15%,stone powder can increase the compactness of RCC,thereby enhancing the mechanical strength of RCC.However,when stone powder content is more than 15%,the mechanical properties of RCC decrease,and its mechanism is analyzed.Secondly,Midas model is used to analyze the stress distribution in the mechanical properties test of RCC cylinder specimens and the fitting between the numerical simulation value and the measured value.(3)In the fifth chapter,the impact resistance,wear resistance,dry shrinkage,impermeability and fatigue properties of RCC with 5 kinds of stone powder content ranging from 0% to 20% are studied.The influence rules of stone powder content on impact resistance,wear resistance,dry shrinkage,impermeability and fatigue performance of RCC are obtained.It is concluded that the durability of RCC can be enhanced when the stone powder content is not more than 10%.The mechanism of the influence of stone powder on the durability of RCC is analyzed.It is concluded that in the construction design of RCC pavement,the content of stone powder in machine-made sand should be controlled.Comprehensive analysis shows that proper amount of stone powder can improve the mechanical properties and durability of RCC.When the content of stone powder is 10%,the performance of RCC is the best,which has strong economy and practicability.