高強大流動度混凝土的制備及應(yīng)用研究
發(fā)布時間：2019-03-02 09:08
【摘要】：本文采用三類流變儀，研究了水泥漿體、砂漿以及混凝土的流變特性。首先，從流變學(xué)的角度討論了顆粒級配對水泥基材料的影響，從而得出了適合制備高強大流動度混凝土的礦物摻合料的最優(yōu)配合比以及細集料和粗集料的最優(yōu)級配曲線。水泥基材料流變學(xué)研究結(jié)果表明，當(dāng)粉煤灰與礦粉的質(zhì)量比為2:1，且總量占膠凝材料總質(zhì)量的30%時，膠凝材料漿體具有較高的流動性和力學(xué)性能。與此同時，研究發(fā)現(xiàn)一個相對較寬的膠凝材料粒徑分布有利于改善漿體的流動性。對砂漿流變性研究結(jié)果表明，中砂適合制備普通大流動度混凝土，然而細度模數(shù)小于3.30的粗砂更適合制備高強大流動度混凝土。在制備大流動度混凝土?xí)r，我們應(yīng)該更多的去注意各粒徑范圍內(nèi)的砂粒質(zhì)量百分比。一般來說，0.315mm以下的砂粒量百分比在15%-30%之間為宜；0.6mm以下的砂粒質(zhì)量百分比在30%-45%之間為宜；1.18mm以下的砂粒質(zhì)量百分比在55%-75%之間為宜。粗集料對流變性能研究結(jié)果表明，粗集料的級配對新拌混凝土的流動性影響最大，而對混凝土力學(xué)性能影響較小。當(dāng)制備高強大流動度混凝土?xí)r，粒徑在4.75mm-9.5mm之間的粗集料質(zhì)量百分比在30%-50%之間為宜；粒徑在16mm-19mm之間的粗集料質(zhì)量百分比在20%-30%之間為宜。在混凝土流動性要求不是很高的情況下，粒徑在16mm-19mm之間的粗集料質(zhì)量百分比可以放寬到10%-40%。 在前期大量試驗的基礎(chǔ)上，制備了符合工程要求的C60和C80泵送混凝土以及C80自密實混凝土。最后，通過流變儀測試C80泵送混凝土和C80自密實混凝土的流變參數(shù)。試驗發(fā)現(xiàn)，粗集料的砂漿包裹層厚度是引起C80泵送混凝土和C80自密實混凝土流變性差異的主要原因。當(dāng)砂漿包裹層厚度大于2mm時，自密實混凝土具備良好的流動性和密實效果。如果C80泵送混凝土的粗集料的砂漿包裹層厚度超過2mm，C80泵送混凝土也具有一定的自密實能力，但是它的流動性能很大程度上取決于粗集料的最大粒徑。
[Abstract]:In this paper, the rheological properties of cement paste, mortar and concrete are studied by three kinds of rheometer. Firstly, the influence of particle size on cement-based material is discussed from the point of view of rheology, and the optimal mix ratio of mineral admixture suitable for preparing high strength fluidity concrete and the optimal gradation curve of fine aggregate and coarse aggregate are obtained. The rheological study of cement-based materials shows that when the mass ratio of fly ash to mineral powder is 2? 1 and the total amount is 30% of the total mass of cementitious materials, the cement paste has higher fluidity and mechanical properties. At the same time, it is found that a relatively wide particle size distribution of cementitious material is beneficial to improve the fluidity of slurry. The rheological behavior of mortar shows that medium sand is suitable for preparing ordinary high fluidity concrete, but coarse sand with fineness modulus less than 3.30 is more suitable for preparing high mobility concrete. When preparing high fluidity concrete, we should pay more attention to the percentage of sand particles in the range of particle size. Generally speaking, the percentage of sand under 0.315mm is between 15% and 30%; the percentage of sand under 0.6mm is between 30% and 45%; and the percentage of sand under 1.18mm is between 55% and 75%. The results of the study on the convective behavior of coarse aggregate show that the gradation of coarse aggregate has the greatest influence on the fluidity of fresh concrete, but has little effect on the mechanical properties of concrete. When the high strength fluidity concrete is prepared, the mass percentage of coarse aggregate between 4.75mm-9.5mm and 16mm-19mm is between 30% and 50%, and the mass percentage of coarse aggregate between particle size between 20% and 30% is suitable. When the fluidity requirement of concrete is not very high, the mass percentage of coarse aggregate with particle size between 16mm-19mm can be relaxed to 10% and 40%. C60 and C80 pumping concrete and C80 self-compacting concrete were prepared on the basis of a large number of previous tests. Finally, the rheological parameters of C _ (80) pumping concrete and C _ (80) self-compacting concrete were tested by rheometer. It is found that the thickness of mortar envelope of coarse aggregate is the main reason for the difference of rheological properties between C80 pumping concrete and C80 self-compacting concrete. When the thickness of mortar coating is greater than that of 2mm, self-compacting concrete has good fluidity and compacting effect. If the thickness of mortar envelope of coarse aggregate of C80 pumping concrete is more than 2mm, C80 pumping concrete also has certain self-compacting ability, but its flow performance depends largely on the maximum particle size of coarse aggregate.
【學(xué)位授予單位】：西南科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2013
【分類號】：TU528
本文編號：2432907
[Abstract]:In this paper, the rheological properties of cement paste, mortar and concrete are studied by three kinds of rheometer. Firstly, the influence of particle size on cement-based material is discussed from the point of view of rheology, and the optimal mix ratio of mineral admixture suitable for preparing high strength fluidity concrete and the optimal gradation curve of fine aggregate and coarse aggregate are obtained. The rheological study of cement-based materials shows that when the mass ratio of fly ash to mineral powder is 2? 1 and the total amount is 30% of the total mass of cementitious materials, the cement paste has higher fluidity and mechanical properties. At the same time, it is found that a relatively wide particle size distribution of cementitious material is beneficial to improve the fluidity of slurry. The rheological behavior of mortar shows that medium sand is suitable for preparing ordinary high fluidity concrete, but coarse sand with fineness modulus less than 3.30 is more suitable for preparing high mobility concrete. When preparing high fluidity concrete, we should pay more attention to the percentage of sand particles in the range of particle size. Generally speaking, the percentage of sand under 0.315mm is between 15% and 30%; the percentage of sand under 0.6mm is between 30% and 45%; and the percentage of sand under 1.18mm is between 55% and 75%. The results of the study on the convective behavior of coarse aggregate show that the gradation of coarse aggregate has the greatest influence on the fluidity of fresh concrete, but has little effect on the mechanical properties of concrete. When the high strength fluidity concrete is prepared, the mass percentage of coarse aggregate between 4.75mm-9.5mm and 16mm-19mm is between 30% and 50%, and the mass percentage of coarse aggregate between particle size between 20% and 30% is suitable. When the fluidity requirement of concrete is not very high, the mass percentage of coarse aggregate with particle size between 16mm-19mm can be relaxed to 10% and 40%. C60 and C80 pumping concrete and C80 self-compacting concrete were prepared on the basis of a large number of previous tests. Finally, the rheological parameters of C _ (80) pumping concrete and C _ (80) self-compacting concrete were tested by rheometer. It is found that the thickness of mortar envelope of coarse aggregate is the main reason for the difference of rheological properties between C80 pumping concrete and C80 self-compacting concrete. When the thickness of mortar coating is greater than that of 2mm, self-compacting concrete has good fluidity and compacting effect. If the thickness of mortar envelope of coarse aggregate of C80 pumping concrete is more than 2mm, C80 pumping concrete also has certain self-compacting ability, but its flow performance depends largely on the maximum particle size of coarse aggregate.
【學(xué)位授予單位】：西南科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2013
【分類號】：TU528
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