| Coal gangue is an selected industrial solid waste in the coal mining, coal washing and the coal preparation process. While after the fuel burning in nature of hiding in the coal spontaneous, combustion coal gangue was created. Spontaneous combustion coal gangue as base material for fine grinding process, reaching a certain fineness can be the powder materials-spontaneous combustion gangue powder(SCGP). This paper highlights the domestic shortage of high quality concrete admixture, relying on the committee project of National Natural Science and the limited company of ShenHua group, it is the subprojects of the (U1261122).Studying of the feasibility that SCGP as the concrete admixture and the affect to performance of concrete, and trying to develop a new variety of concrete admixture, explore the new way of spontaneous combustion coal gangue resource application.This paper firstly arouse the potential activity of SCGP by mechanical activation method. According to the SCGP-cement mortar fluidity and strength test results, and the grinding energy consumption to determine the economic grinding time of spontaneous combustion coal gangue. On this basis, by the orthogonal test of concrete consistency and strength, with choosing the proportion of SCGP and the varieties and proportion of water reducer as influencing factors to research the compatibility of SCGP and two kinds of water reducer. Finally, taking the SCGP as concrete admixture to research the Influence of SCGP dosage to concrete resistance to chloride ion permeability and frost Financial resistance. To provide for the basis ensurence with engineering application of SCGP mineral admixture. This paper draws the following conclusion:(1) Fuxin Qinghemen mine spontaneous combustion of coal gangue grindability index is higher, when the grinding time is 4?6min, the activity index higher than class I fly ash, but slightly inferior S95 powder and cement, mortar fluidity between with fly ash and slag powder, and satisfied the basic requirements as mineral admixture of concrete.(2) SCGP admixture with different varieties of superplasticizer composite double mixed, compatibility is different, the degree of compatibility:polycarboxylic acid (Poly)> naphthalene (Nap)> lignin. It can display excellent compatible performance when the SCGP and Poly double doped.(3) Comparison the concrete consistency and strength rules with different SCGP dosage, different varieties of water reducing agent and admixture found that SCGP content improved a certain extent to the mixture cohesion and water retention, the influence to initial slump and the loss is not obvious, but have a certain effect on the concrete compressive strength of 7d when with Nap water reducing agent double doped, especially the late strength growth rate faster than pure cement concrete. The influence of varieties and dosage of reducing agent to SCGP admixture concrete workability and strength are not obvious.(4) SCGP with incorporation of small although reduce early strength of concrete, but the strength and durability performance for concrete development. SCGP reduced the content of harmful holes in hardened, curing the ingress of chloride ions in the system.The concrete anti chlorideion penetration level of 60d was "very low" when SCGP content is 35%.The frost resistance grade of concrete at least can reach more than F1200 when SCGP content is 15%. As long as control the water cement ratio, ensure the compactness of concrete, it also can get higher strength and better frost even if the amount of coal gangue admixture is bigger, resistance. |
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