中高强再生混凝土配合比设计及力学性能研究

发布时间：2018-04-17 22:31

本文选题：中高强再生混凝土 + 配合比设计　；参考：《辽宁工程技术大学》2015年硕士论文

【摘要】：随着城市化的发展,产生了大量的建筑垃圾,其中大部分是废弃混凝土,大量的废弃混凝土对社会环境已经造成了巨大的污染；废弃混凝土再生利用的形势迫在眉睫,混凝土行业的发展必须走可持续发展的道路。利用再生混凝土配制技术,不仅可以解决废弃混凝土引起的环境污染问题,还可以给社会带来一定的经济效益。目前,再生混凝土的研究及应用局限于低强度方面,中高强再生混凝土的研究尚未有系统的研究。本文旨在研究中高强再生混凝土的配合比设计及其基本力学性能方面,探讨适用于再生骨料的二次搅拌工艺、利用低强度再生骨料配制中高强再生混凝土的可行性及利用神经网络技术对中高强再生混凝土进行强度预测。本文研究路线为水泥(42.5普硅)+活性矿物掺合料(硅灰和粉煤灰双掺技术)+高效减水剂(萘系减水剂),基于本文的研究成果(改进的二次搅拌工艺),成功的实现了再生混凝土高强化的目标,为再生混凝土的推广应用提供一定的理论基础与参考价值。以水胶比(A)、再生粗骨料替代率(B)、硅灰掺量(C)和粉煤灰掺量(D)为影响因素,各有四个水平,采用正交表L16(45)安排了16组正交试验。通过对7d、28d和60d正交试验结果的极差分析和方差分析,分析各因素各水平对中高强再生混凝土的基本力学性能的影响。并得出28d立方体抗压强度的最佳配合比是：A2B3C4D2,即水胶比=0.32,再生粗骨料取代率=75%,硅灰掺量=10%,粉煤灰掺量=15%。且结果表明75%与100%取代时抗压强度差异小,在5%以内,所以为了使再生粗骨料利用达到最大化,综合分析得出最优组合：A2B4C4D2。对中高强再生混凝土28d后抗压强度进行多元线性回归分析可知,抗压强度与胶水比确实不呈简单的线性关系,这也是bolomey公式不适用于中高强再生混凝土的根本原因。利用SPSS神经网络对中高强再生混凝土7d、28d和60d立方体抗压强度进行预测,结果显示各个观测点的预测情况良好。说明应用现代电脑科技对工程材料进行强度预测是十分有利的,也具有一定的可靠性和前瞻性。本文仿照斯拉特公式进行中高强再生混凝土的7d抗压强度和28d抗压强度之间的非线性回归,结果为f28=f7+2.185(f7)0.5。应用此式,可由所测得的中高强再生混凝土的早期(7d)强度,来估算其28d龄期的强度。这对以后中高强再生混凝土在实际应用时,由此可控制生产施工的进度,如确定混凝土拆模、构件起吊、放松预应力钢筋、制品堆放、出厂等的日期提供了一定理论基础,具有一定的参考价值。
[Abstract]:With the development of urbanization, a large amount of construction waste, most of which is waste concrete, has caused huge pollution to the social environment.The development of concrete industry must take the road of sustainable development.Using recycled concrete preparation technology can not only solve the problem of environmental pollution caused by waste concrete, but also bring certain economic benefits to the society.At present, the research and application of recycled concrete is limited to low strength, and the research of medium and high strength recycled concrete has not been systematically studied.The purpose of this paper is to study the mix ratio design and basic mechanical properties of medium and high strength recycled concrete, and to discuss the secondary mixing process suitable for recycled aggregate.The feasibility of making medium and high strength recycled concrete with low strength recycled aggregate and the prediction of strength of medium and high strength recycled concrete by neural network technology are discussed.The research route of this paper is cement 42.5% silicon) active mineral admixture (silica fume and fly ash) high efficiency water reducing agent (naphthalene water reducing agent). Based on the research results of this paper (improved secondary stirring process), it has been successfully realized.The goal of high reinforcement of recycled concrete,It provides a certain theoretical basis and reference value for the popularization and application of recycled concrete.With water / binder ratio (An), replacement ratio of regenerated coarse aggregate (B), silica fume content (C) and fly ash content (D) as the influencing factors, there were four levels in each group, and orthogonal experiments were arranged in 16 groups by orthogonal table L16C45).The effects of various factors and levels on the basic mechanical properties of medium and high strength recycled concrete were analyzed by means of the range analysis and variance analysis of the results of 7 d and 60 d orthogonal tests.The optimum mixture ratio of 28d cube compressive strength is: W A 2B 3C 4D 2, that is, water / binder ratio is 0.32, replacement rate of regenerated coarse aggregate is 75 / 75, silica fume is 10 and fly ash is 15.The results show that the difference of compressive strength between 75% and 100% is small, less than 5%. In order to maximize the utilization of recycled coarse aggregate, the optimum combination: A2B4C4D2 is obtained by comprehensive analysis.The multivariate linear regression analysis of the compressive strength of medium and high strength recycled concrete after 28 days shows that there is no simple linear relationship between the compressive strength and the ratio of glue, which is the fundamental reason why the bolomey formula is not suitable for the medium and high strength recycled concrete.The SPSS neural network is used to predict the compressive strength of medium and high strength recycled concrete cubes for 7d ~ 28d and 60d respectively. The results show that the prediction of each observation point is good.It shows that the application of modern computer science and technology to the strength prediction of engineering materials is very advantageous, and also has certain reliability and foresight.In this paper, the nonlinear regression between the 7d compressive strength and 28d compressive strength of medium-high strength recycled concrete is carried out according to the Slatter formula. The result is f28=f7 2.185 f7c0.5.Using this formula, the early strength of medium and high strength recycled concrete can be estimated from the early stage of 7 d) strength of the medium and high strength recycled concrete, and the strength of the medium and high strength recycled concrete can be estimated at 28 d age.This provides a certain theoretical basis for determining the dates of concrete demolition, lifting of members, lifting of prestressed steel bars, stacking of products, leaving the factory, etc., when the medium and high strength recycled concrete is in practical application, and thus the progress of production construction can be controlled.It has certain reference value.
【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】：2015
【分类号】：TU528

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