Stone Chips Concretes Performance And Environmental Efficiency

Since the increase of recent years foundation engineering construction as well as the urbanized acceleration, our country's concretes output climbed year after year. This lead to an increasing demand of the structural purpose granulated substance year by year, resulting excessive consumption of the massive resources. The granulated substance is one of concretes basic materials, and in our country , structural purpose granulated substance is made from river sand primarily. For those stone aggregate occupying more than 70% of the concretes, mining and river excavation are two main resources for obtaining the stones, which in a turn, seriously destroy the natural ecological environment. Meanwhile many local high quality natural sand are tight, in short of demand. On the other hand, the storage of stone chips occupied large amounts of land meanwhile caused environmental pollution. In our country existing various tailings nearly 5,000,000,000 tons, the maintenance expense reaches several ten million every year, creating the massive resources waste and the environmental pollution. The stone chips is the quarry the sideline product which remains down in the processing crushed stone's process processes specially with the crushed stone becomes, its particle size being suitable, and the price is cheap. The physical property target of stone chips match with the natural sand and the efficiency is quite good, which is one kind of good generation of granulated substance material. Our country have rich stone chips resources, therefore replaces the natural sand with the stone chips to compound concretes not only can reduce the river destruction and ecological destruction because of the sand ,but can solve the question that the natural sand resources shortage in our country, also can save resources, protect the environment, it also saves construction costs meanwhile bring considerable economic benefits.In order to deepen people's understanding in stone chips replace nature sand, and to proof the substitutability ,this paper adopting high close-grained accumulation theory and Wu Zhongwei's most Jan mixture ratio for different grain shapes and material qualities to design concretes, and compound medium and high strength concrete. According to workability, mechanical properties, durability and microscopic structure compared to stone concrete and sand concrete, the research indicated:1,Used the stone chips powder to mix the system the concretes, improved the concretes workability. Compared with the Douluo granulated substance concretes, the stone chips powder concretes non-weeping phenomenon, the cohesive properties coherency is good. The workability, the water retention property are also better than the Douluo granulated substance concretes. 2, The mechanical properties of stone chips concretes mechanical properties in general better than Douluo granulated substance concretes.3, Compares with the Douluo granulated substance concretes, the stone chips powder concretes' durability is better. Its anti-impact ability achieves the Douluo granulated substance concretes'1.6 times; The anti-permeability label also enhanced a rank; The anti-frozen intensity loss factor must be lower than the Douluo granulated substance concretes, and the air shrinkage situation much better than Douluo granulated substance concretes; Moreover by joining stone chips powder the carbonation depth of concrete will be smaller, the possibility and degree of Rebar corrosion will be lower.4, By the SEM picture and the hole structure analysis may be known. The ultra fines of stone chips ultra plays role update of particles in the concretes. They can improve the concretes'hole structure effectively, cut the factor of porosity, and reduce the bore size, which caused the concretes to form the dense packing structure and the viewing carefully level from the close stack system, thus improved the concretes overall performance effectively, enabled the concretes not only to have the good physical mechanics performance also to enhance the concretes durability.5, By the X- diffraction may be known, because of the stone chips fine dust's nucleus function, promoted the cement early hydration, Ca(OH)2 and the stone chips ultra fine dust production basic calcium carbonate, strengthened the frontal zone caking, have a significant contributes to the concretes intensity. Simultaneously had also indicated the stone chips powder not solely is one inertia mixes the material, but with the surrounding medium happened reaction.6, Stone material is rich, the price is cheap, with it compound concrete instead of nature sand can solve the problem in the process of quarrying stone chips occupied large amounts of land, also can reduce river damage and natural ecological destruction caused by dig sand, and reduce the environment pollution greatly, so it has a broad prospect of application and environmental benefits.