Influence Of Oil Shale Ash On Properties Of Large Volume Concrete

In recent years, as oil, coal, natural gas and other traditional energy reduction and the development of the industry, all kinds of alternative energy research and development are obviously rising trend. Oil shale as a kind of unconventional oil and gas resources is abundant, can extract oil shale oil similar to oil, can also be used for burning to generate electricity, for this reason, recently all the countries in the world have strengthened the research of exploration and utilization of oil shale. At present, for the use of oil shale, more than 90% is used for combustion power generation or refining shale oil, a large number of ash will be produced in use process because of low oil content and high ash content in oil shale. At present, the main method of dealing with the ash is stacked aside, this treatment not only occupies the land, and pollute the environment, but also is a waste of resources. Therefore, processing and utilization of oil shale ash has become a hot topic of research in recent years.The ultrafine oil shale ash in this paper was got by grinding oil shale primary ash made in Yantai Longfeng thermal power plant to a certain fineness, and had the high chemical activity. This article selected the Portland cement clinker grinding P.O42.5 cement with C3 A content less than 7%, the S95 grade slag powder, the secondary fly ash and the ultrafine oil shale ash as raw material, according to the performance characteristics of the material to optimize the mass concrete mix ratio. In different gelling material ratio, by studying water binder ratio on working performance and mechanical properties of large volume concrete, the aim was to determine an appropriate water binder ratio for the test. Under a certain water binder ratio, influence of oil shale ash replacing cement on the properties of concrete was studied. Under the same water cement ratio and cement dosage, influence of oil shale ash instead of fly ash content on the performance of concrete was studied. Through the working performance, mechanical properties, internal temperature rise and other macro detection method, as well as the particle size analysis, XRD, SEM, hydration heat and microscopic test technology, the oil shale ash and its application in mass concrete were analyzed. Through this study, the following conclusions are obtained.(1) Grinding oil shale original ash for 30 min, the 7d and 28 d activity index are respectively 88% and 98%, reach S95 grade powder activity level. Oil shale ash particles are mainly irregular shape debris, water demand is relatively high and is 105%;(2) When water binder ratio is 0.37, concrete mixing slurry is so viscosity that is difficult to pump, and the admixture dosage is more, resulting in slurry coagulation time is too long and affects the construction progress; Water cement ratio is 0.41, the later strength of concrete is lower,, the mechanical properties cannot be guaranteed. Therefore, combining with the working performance and mechanical properties to comprehensive consideration, the suitable water binder ratio for this paper is 0.39;(3) Under water binder ratio is 0.37, in the per cubic concrete, cement dosage is in 180~280 kg, and the ultrafine oil shale ash dosage is accordingly 100~0kg, the 28 days strength of concrete is between 43 MPa and 47 MPa, the 7 days adiabatic temperature is in the range of 45℃ to 49℃.In addition, after the oil shale ash replacing an equal amount of fly ash, water demand of concrete is increasing, and workability is worse, but later strength is bigger;(4) Compared with sand and gravel as aggregate concrete, internal temperature of standard sand as coarse and fine aggregate concrete is lower, low around 3℃. The internal temperature of concrete are greatly influenced by sand and gravel aggregate. Under the same gelled material and water binder ratio, concrete temperature changes with different aggregate. Using the standard sand instead of coarse and fine aggregate to test concrete internal temperature rise, this is a scientific and suitable method to measure internal temperature of large volume concrete.