自燃煤矸砂预处理对混凝土性能影响试验研究

发布时间：2018-05-08 03:38

本文选题：自燃煤矸砂混凝土 + 细集料预处理　；参考：《辽宁工程技术大学》2014年硕士论文

【摘要】：自燃煤矸石集料以其质量较好、储量较大、易开采、价格低廉的特点,在轻集料家族中占一席之地。但随着预拌混凝土的广泛应用,自燃煤矸石集料由于孔隙率大、吸水率高,搅拌过程中吸收混凝土中的拌合水,使拌合物干稠,坍落度较小。另外,对自燃煤矸石集料配制的混凝土耐久性研究也较少。本文是国家自然科学基金委员会与神华集团有限公司联合资助项目—“煤矸石在水泥和混凝土中资源化利用关键科学问题研究”(U1261122)中的子项目,通过采取对自燃煤矸砂预处理、复掺矿物掺合料、外加剂等技术途径,实现配制大流动性、高耐久性自燃煤矸砂混凝土的配制目标。取得如下研究成果：(1)机械破碎的自燃煤矸砂,颗粒级配较差,若与天然砂合理组配,可以满足混凝土用细集料的质量要求。(2)通过对自燃煤矸砂预处理,以及复掺高效减水剂、矿物掺合料,当自燃煤矸砂全部取代天然砂,仍可配制出大流动、中等强度、高耐久性的自燃煤矸砂混凝土。(3)自燃煤矸砂的附加用水为吸水率60%,且提前10min吮水润湿,拌合物在保证大流动性预拌混凝土配制要求的基础上,硬化强度等级也能满足结构设计要求。(4)中等强度等级的自燃煤矸砂混凝土正交试验表明,胶凝材料之间的质量比对混凝土拌合物坍落度影响显著；外加剂之间的质量比对拌合物坍落度影响不显著。当水泥：粉煤灰：矿粉=80：10：10,减水剂：引气剂=0.8：0.2时,拌合物在保证粘聚性和保水性良好的前提下,坍落度最大；外加剂之间的质量比、胶凝材料之间的质量比对混凝土28d抗压强度影响都比较明显,影响程度为：外加剂之间的质量比大于胶凝材料之间的质量比。当水泥：粉煤灰：矿粉=80：10：10,减水剂：引气剂=1：0时,混凝土抗压强度达到最高。(5)自燃煤矸砂混凝土抗氯离子渗透和抗冻性试验表明,外加剂之间的质量比对自燃煤矸砂混凝土抗氯离子渗透性能影响特别显著,胶凝材料质量比对抗氯离子渗透无明显影响；当冻融循环次数小于100次时,两因素对其影响均不明显,但当冻融循环次数大于150次时,胶凝材料质量比对抗冻性能影响程度逐渐明显。
[Abstract]:The spontaneous combustion gangue aggregate has the characteristics of good quality, large reserves, easy mining and low price, so it occupies a place in the light aggregate family. However, with the wide application of ready-mixed concrete, the spontaneous combustion gangue aggregate has high porosity and high water absorption, and absorbs the mixing water in the mixing process, which makes the mixture dry thick and the slump is small. In addition, the durability of concrete prepared by spontaneous combustion gangue aggregate is less. This paper is a sub-project of the National Natural Science Foundation Committee of China and Shenhua Group Co., Ltd., which is a sub-project of "Research on the key Scientific problems of the Utilization of Coal gangue in cement and concrete". The compounding of mineral admixture and admixture can achieve the preparation goal of high fluidity and high durability self-burning gangue sand concrete. The following research results are obtained: 1) the grain gradation of mechanically broken self-coal gangue sand is poor. If it is properly combined with natural sand, it can meet the quality requirement of fine aggregate for concrete. Mineral admixture, when the natural sand is completely replaced by the self-coal gangue sand, it can still be prepared with large flowing, medium strength and high durability self-coal gangue sand concrete. On the basis of ensuring the preparation requirement of high fluidity ready-mixed concrete, the hardening strength grade can also meet the structural design requirements. 4) the orthogonal test of self-coal gangue sand concrete with medium strength grade shows that, The mass ratio of cementitious material has a significant effect on the slump of concrete mixture, while the mass ratio of admixture has no significant effect on the slump of concrete mixture. When cement: fly ash: mineral powder 80: 10: 10, water reducer: air entraining agent = 0.8: 0.2, the mixture has the highest slump under the premise of good cohesion and water retention; the mass ratio between admixtures, The influence of the mass ratio of the cementing materials on the compressive strength of concrete for 28 days is obvious, and the influence degree is that the mass ratio between admixtures is greater than the mass ratio between the cementing materials. When cement: fly ash: mineral powder 80: 10: 10, water reducer: air entraining agent 1: 0, the compressive strength of concrete reaches the highest. The effect of the mass ratio between admixtures on the chloride ion permeability of the concrete from coal burning gangue sand is particularly significant, and the cement material mass ratio has no obvious effect on the chloride ion permeation, and when the freeze-thaw cycle times are less than 100 times, However, when the freeze-thaw cycles were more than 150 times, the effect of the mass ratio of the cementing material on the freezing resistance was gradually obvious.
【学位授予单位】：辽宁工程技术大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528

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