Orthogonal Experimental Study on Concrete Properties of Machine-Made Tuff Sand

Abstract

Machine-made sand instead of natural sand has become an inevitable choice for the sustainable development of the concrete industry. Orthogonal experiment and grey correlation analysis were used to investigate the performance of machine-made tuff sand concrete. The optimal concrete mix ratio of machine-made sand was obtained by orthogonal test and its working performance was verified. Grey correlation analysis was applied to compare the factors affecting the mechanical properties of the machine-made sand concrete. The test results show that the sand rate has the greatest degree of influence on slump and slump expansion. The mineral admixture has the greatest effect on the 7-day compressive strength of the concrete. Additionally, the water–cement ratio has the greatest influence on the 28-day compressive strength. The mechanical and working properties of the machine-made sand concrete reach the optimum condition when the mineral admixture is 20%, the sand rate is 46%, the stone powder content is 10% and the water–cement ratio is 0.30. Comparing different fine aggregate concretes of similar quality, we conclude that the mechanical and working properties of tuff sand concrete and limestone sand concrete and river sand concrete are similar. The compressive strengths of the mechanism concrete show the greatest correlation with roughness and the least correlation with stone powder content. The stone powder content has almost no effect on the compressive strength of concrete when the stone powder content does not exceed a certain range. The results of the study point out the direction for the quality control of concrete with machine-made sand.

Experimental Study and Analysis on Workability and Mechanical Performance of High Fluidity Recycled Concrete

“…With the increase in sand ratio, the filling effect of sand and the ball effect becomes more and more obvious, and the high fluidity of recycled concrete increases. This is relatively similar with the results of the literature [ 36 ], but the sand rate used in this paper is relatively small, so the conclusion obtained is that the flow rate increases continuously with increasing sand rate. The maximum increase value of the slump of NC-0, RC-30, RC-40, and RC-50 recycled concrete is 15 mm, 25 mm, 15 mm and 30 mm, respectively, with different sand ratios.…”

Experimental Study on the Properties of Mortar and Concrete Made with Tunnel Slag Machine-Made Sand

“…The properties of concrete with different stone powder content and fineness modulus were tested. Gray-correlation analysis was used to calculate the correlation between the stone powder content, fineness modulus and the slump, strength of concrete [ 6 ].…”

“…The lack of sand resources in China has led to the rapid development of the building materials industry, which has begun to use a large amount of machine-made sand [ 3 , 4 , 5 ]. Studies have shown that compared with natural sand, artificial sand has the advantages of abundant resources and controllable quality [ 6 ]. Machine-made sand is a kind of artificial sand made of stone crushed and screened by a sand-making machine, and the particle size is mostly less than 4.75 mm.…”

“…The most obvious difference between the machine-made sand and natural sand is that the machine-made sand will produce stone powder with particle size less than 0.075 mm. The limit value of stone powder is 10% according to the national standard in China, but the content of artificial sand in actual production is usually as high as 10–20% [ 6 ]. The stone powder in the artificial sand is different from the mud powder in natural river sand.…”

“…The limit value of stone powder is 10% according to the national standard in China, but the content of artificial sand in actual production is usually as high as 10-20% [6]. The stone powder in the artificial sand is different from the mud powder in natural river sand.…”