The Study On The Application Of Wastes From Stone Processing Industry In Cement And Concrete

With the rapid development of China's economy, stone processing industry has been rapidly developped, and the waste pollution generated is increasingly serious and caused serious damage to the ecological environment. How to find a fundamental solution to the problem of pollution of stone waste from a realistic point of view, is the starting point of this paper. Mainly using the stone waste discharged in Yunfu stone processing industry, this paper carried out the application research of the stone-industry wastes in cement, dry-mixed mortar, concrete.Firstly this paper tested the basic physical properties of the stone waste powder, and then studied the properties of cement, dry-mixed mortar, cocrete using the stone waste powder as addition.The results showed that the stone waste powder from Yunfu was mixture of marble powder, granite powder, artificial stone powder. The stone waste powder mainly contain CaO, SiO2 in chemical composition, CaO accounting for about 30% and SiO2 accounting for about 27%; The stone waste powder is mainly composed of high crystallinity calcite and quartz, also contain small amounts of feldspar and mica and other minerals in mineral composition; the stone waste powder is composed of 40% granite and 60% mixture which was mixed by a mass of marble powder and a small quantity of artificial stone powder. The test results of particle size distribution showed that most of the stone waste powder are fine particles,57% of the powder's particle size being less than 30μm; In the stone waste powder, the marble powder is more of circularity and fineness, and the granite powder is less of circularity and fineness.Compared to the volcanic ash, using the stone waste powder as a cement addition reduced the setting time of cement slightly. the waste stone powder's specific surface area had a little effect on the setting time of the cement. Using the stone waste powder as a cement mixing materials, the early strength of cement was improved, but late strength of cement was reduced. The marble powder in the stone waste powder was advantageous to the development of the early strength of cement, the granite powder in the stone waste powder was advantageous to the development of the late strength of cement and the artificial stone powder was harmful to the cement strength in various ages. At the same time the artificial stone powder in the stone waste powder was negative to the dry shrinkage and the wear resistance of the cement. Using the stone waste powder to replace small or all of fly ash in dry-mixed mortar may reduce the water/cement ratio, improve the coursing degree and shorten the setting time of mortar. As the stone waste powder had less the active ingredient, Using the stone waste powder to replace small or all of fly ash would reduce the later strength of the mortar.Compared to fly ash, using the waste stone powder as concrete addition improved the fine aggregate gradation and the performance of concrete. When the stone waste powder content raise from 10% to 20%, the workability of the concrete was improved, the early strength of concrete was gradually increased and the later strength was reduced. When the waste stone powder replaced the fly ash, the anti-carbonation of concrete significantly increased, and the mixing amount was higher, the performance of concrete carbonation resistance was better, but the chloride-penetration resistance was worse. Meanwhile the marble and granite parts were conducive to the improvement of anti-carbonation, but the marble part was negative to the chloride-penetration resistance of concrete.