Study on engineering characteristics of red sandstone mechanism sand in chishui jiading group
[Objective]The red-bed area of Chishui is renowned for its Danxia landform.However,the predominant cool-toned slope protection materials used in this region are incongruous with the natural coloration of the original rock formations within the scenic area.In order to develop a new type of slope protection material in line with the landscape coordination in the red layer area of Chishui,the red layer sandstone was crushed into mechanism sand as raw material,and the essential characteristics of the mechanism sand were tested.[Methods]The machine-made sand mortar was prepared by using red-bed sandstone machine-made sand as an admixture.The compressive strength,water retention rate,and consistency of mortar at 3 d,7 d,and 28 d under dif-ferent gradations were tested to obtain the optimal gradation of machine-made sand mortar.Under the optimal gradation,the per-formance of machine-made sand mortar with different sand-binder ratios,stone powder content,and water-retaining agent content was tested by orthogonal experiment.[Results]The result show that in the best gradation test,the mortar's 28 d compressive strength increases with the fineness modulus.When the fineness modulus is 2.98,the water retention rate and consistency are the best.In the optimal ratio test,the compressive strength,flexural strength,tensile bond strength,and nuclear magnetic resonance porosity of machine-made sand mortar are inversely proportional to the sand-binder ratio,stone powder content,and water-retai-ning agent content.The content of stone powder has the most significant influence on the color difference of mortar.[Conclu-sion]The basic characteristics of red-bed sandstone machine-made sand meet the specification requirements,and the gradation characteristics are'dumbbell-shaped.'The optimal gradation fineness modulus of machine-made sand mortar is 3.31.The com-pressive strength,flexural strength,tensile bond strength,nuclear magnetic resonance porosity,and color performance are the best under the conditions of sand-binder ratio of 2.5,stone powder content of 22％,and water-retaining agent content of 0.22％.The mortar prepared by red sandstone manufactured sand meets the M10 mortar standard and the color mortar is close to that of sandstone.
red sandstoneslope protectionlandscape coordinationmachine-made sand stoneorthogonal experimentmechan-ical propertiesinfluencing factorscompressive strength
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