Study On The Activity And Application Of Coal Gangue

From the view of environmental resources, coal gangue have residue and resources dual attributes. Mainly based on the "resource" utilization of this industrial waste residue, resolving practical problems in the industrial production, purposes of conserving energy protecting the environment and recycling Bao, the activated coal gangue was researched as the complementary cementitious component.In the paper, we received the best activation patterns and the best content of coal gangue in cement mortar by studying the activity of the coal gangue.At the same time, dry-mixed mortar has many advantages such as stable quality, constructing expediently, using byproducts, good to environment, meeting the needs of various projects. It has broad prospects of development. Therefore, in the paper, based on the research of coal gangue, we designed mixture ratio of masonry dry-mixed mortar, which doped activated coal gangue and fibrous brucite.In view of characteristics of composition and structure of coal gangue, the coal gangue was activated by the mean of mechanical–thermal complex activation at first, the characteristic of thermal activated coal gangue at 600～900℃was investigated. The strength of cement mortar was tested after adding the thermal activated coal gangue to Portland cement with a mass fraction of 10%～40%. X-ray diffraction (XRD),differential thermal analysis (DTA),laser-particle size analysis(LPS), polarized optical microscope(PLM) and other modern method of testing were used to analyze the composition and microstructure of the activated coal gangue. The results show that the best mechanical–thermal complex activation is that grinding for the first five hours with ball mill, holding seven hours after heating to 700℃, grinding three hours after natural cooling; The strength of cement mortar descends as content of burned coal gangue increases, but increases with age. The compressive strength at the activated coal gangue content of 30% could reach 61.56MPa,which was 0.33% higher than that of blank specimen. The flexural strength at the activated coal gangue content of 20% could reach 8.56MPa,which was 2.76% higher than that of blank specimen. The best mix quantity is 30%,and the strength descends sharply when the mix quantity more than 35%. active SiO2 and Al2O3 are the main source of coal gangue activity that is created after calcinations of coal gangue analyzed by XRD. After gaining the best activation patterns and the best content of coal gangue in cement mortar,the flexural strength ,compressive strength, bonding strength and consistency of the mortar were tested after adding fibrous brucite and water-reducing agent. The results show that by changing the preparation of gray and sand can be a different intensity levels of dry-mixed masonry mortar at the activated coal gangue content of 30%,the fibrous brucite content of 3%, the Naphthalene superplasticizer content of 1%, and the indicators were in line with norms; Activation gangue with absorbent role. The mortar consumption increased consistency standards, and setting time extended accordingly, but the volume of cement stability were not adversely affected with the increase of Activation gangue content; Complex activation gangue mortar contraction can reduce the shrinkage values of mortar. Because of activated coal gangue have volcanic ash effect and micro-aggregate filling effect,can generate dense hydration C-S-H gel, filling the pores, which not only increased the strength of the mortar, and supported the skeleton supporting role of fibrous brucite, making mortar reduced shrinkage greatly.Through comparative analysis the properties of non-doped fiber and doped fiber mortar found that blending proper quantity of fibrous brucite and water-reducing agent not only resolved the problem of bleeding, but also improved the flowability and strength of cement mortar. The function of water-retaining and anticracking of cement mortar was obvious. It proved that fibrous brucite has a good performance in the cement-based materials once again.In addition, the future work priorities and recommendations were also suggested based on the advantages and disadvantages of the process of experiment and the current status of the activated coal gangue.