摘要:
为综合利用承德地区的钒钛磁铁矿尾矿，以该尾矿为主要原料，制备了高强混凝土制品，研究了尾矿细度、尾矿及减水剂掺入量对样品抗压强度与流动度的影响，分析了样品的组成与结构，检测了其耐硫酸盐侵蚀性能与抗渗透性能。结果表明：添加尾矿降低了样品早期的抗压强度，增大尾矿与减水剂掺入量，减小尾矿的粒径，样品的28 d抗压强度呈先升后降的变化趋势，适当提高尾矿细度与增大减水剂掺入量可提高水泥砂浆的流动度。当尾矿、水泥、高炉渣、石膏与减水剂的掺入量分别为60%、24%、12%、4%与1%，尾矿的细度为-0.074 mm粒度占80.44%时，混凝土制品的28 d抗压强度高达90.2 MPa，满足《高强混凝土结构技术规程》中C50~C80等级的要求。XRD和SEM分析结果表明：制品养护28 d后，生成了针板状的托勃莫来石，针状的钙矾石及无定形态的水化硅酸钙等产物，水化硅酸钙凝胶紧密胶结粗粒骨料，赋予制品较高的抗压强度、优异的耐硫酸盐侵蚀性能与抗渗透性能。
Abstract:
To comprehensively utilize the vanadium titanomagnetite tailings from Chengde area,the high strength concrete products were prepared using the tailings,cement clinker,blast furnace slag and gypsum as raw materials.The effects of fineness of tailings,dosage of tailings and water reducer on the compressive strength and fluidity of the samples were studied.The composition and structure of the samples were analyzed.The sulfate corrosion resistance and permeability resistance of the samples were tested.The results show that the compressive strength of cement mortar increases first and then decreases with the increase in tailings and water reducer dosage as well as decrease of tailings particle size.The fluidity of cement mortar increases with increasing the tailings fineness and water reducer dosage,and the early compressive strength of cement mortar decreases with the tailings addition.When the dosage of tailings,cement,blast furnace slag,gypsum and water reducer is respectively 60%,24%,12%,4% and 1%,and the tailings with-0.074 mm particle size account for 80.44% in amount,the 28-day compressive strength of concrete products reaches 90.2 MPa,which meets the requirements of C50~C80 grade in Technical Regulations for High Strength Concrete Structures.The results of XRD and SEM analysis show that after curing for 28 d,plate-like tobermorite,needle like ettringite and amorphous hydrated calcium silicate can be formed.Hydrated calcium silicate gel tightly cemented coarse aggregate,giving the sample high compressive strength,excellent sulfate resistance and permeability resistance.
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