回弹法推定砌体中普通混凝土多孔砖抗压强度研究

发布时间：2018-02-10 15:41

本文关键词： 回弹法普通混凝土多孔砖影响因素回归分析最小二乘法回弹测强曲线　出处：《湖南大学》2015年硕士论文　论文类型：学位论文

【摘要】：回弹法是一种用一弹簧驱动的重锤,通过弹击杆(传力杆),弹击材料表面,并测出重锤被反弹回来的距离,以回弹值(反弹距离与弹簧初始长度之比)作为与强度相关的指标,来推定混凝土及砖强度的一种方法。回弹法作为现场无损检测中运用较普遍的一种,它具有检测速度快、轻便易携带、操作简单且无破损性的特点。随着回弹法的应用越来越广泛,砌体结构中的烧结砖回弹法检测抗压强度应用越来越普遍,但在非烧结砖中并未得到推广应用。为了保护环境和节约能源,发展轻质、高强和节能的墙体材料,混凝土多孔砖成为各地新型墙体材料的首选产品,但是砌体中混凝土多孔抗压强度的回弹法检测也尚无相关的标准和依据。因此,有必要建立砌体中混凝土多孔砖的统一回弹测强曲线。本文通过试验研究和数据分析,运用数理统计和回归分析的方法,建立了适用于砌体中普通混凝土多孔砖的回弹测强曲线。本文主要内容如下:(1)介绍了混凝土多孔砖的研究过程、发展和特点,对回弹法检测砌体中块材抗压强度的基本原理及其主要影响因素进行了研究分析。通过四川建筑科学研究院和江苏省建筑科学研究院的墙体110块试块,对混凝土多孔砖回弹测试时回弹带肋及不带肋位置的影响进行了研究。(2)通过江苏省建筑科学研究院3片墙体,对不同砂浆强度对回弹值的影响进行了研究。(3)通过湖南大学结构实验室的12个砌体试件,对不同竖向压力、试验方法对回弹值的影响进行了研究。(4)应用Origin9.0软件进行曲线拟合:对于湖南大学结构实验室制作的80块混凝土多孔砖抗压强度试件,采用ZC3-A型混凝土回弹仪进行回弹测试,然后进行抗压强度试验,共得到80组回弹值及其对应的抗压强度。将其按照平均值相差0.5进行分组,得到22组回弹平均值和抗压强度平均值;采用ZC4型砖回弹仪,对湖南大学结构实验室的6个标准混凝土多孔砖砌体试件和四川省建筑科学研究院的3片试验墙片进行回弹测试和抗压强度试验,得到80组回弹值及其对应的抗压强度,并对其分组,得到20组回弹平均值和抗压强度平均值。将两种回弹仪所得试验数据按最小二乘法原理对其分组前后的数据分别进行回归分析,得到以ZC4型砖回弹仪的抛物线函数表达式为混凝土多孔砖回弹测强公式。
[Abstract]:The springback method is a kind of weight hammer driven by a spring. The springback value (the ratio of the rebound distance to the spring initial length) is used as the index of strength related to the strength of the hammer by hitting the surface of the material with a spring bar (force transfer rod), and measuring the distance from which the weight hammer is rebounded. As one of the most popular methods in field nondestructive testing, the springback method has the advantages of high detection speed, portability and portability. With the wide application of springback method, the springback method of sintered brick in masonry structure is more and more widely used to detect the compressive strength. In order to protect the environment and save energy, to develop lightweight, high-strength and energy-saving wall materials, concrete porous brick has become the first choice of new wall materials all over the world. However, there is no relevant standard and basis for the springback test of concrete porous compressive strength in masonry. Therefore, it is necessary to establish the unified rebound strength curve of concrete porous brick in masonry. By means of mathematical statistics and regression analysis, the springback strength curve of common concrete porous brick in masonry is established. The main contents of this paper are as follows: 1) the research process, development and characteristics of concrete porous brick are introduced. The basic principle and main influencing factors of rebound method for testing compressive strength of block in masonry are studied and analyzed. Through 110 test pieces of wall of Sichuan Institute of Building Sciences and Jiangsu Institute of Building Science, In this paper, the influence of rebound ribbed and unribbed position on rebound test of concrete porous brick is studied. The effect of different mortar strength on resilience is studied. Through 12 masonry specimens of structure Laboratory of Hunan University, different vertical pressures are studied. The effect of springback value was studied. (4) the curve fitting was carried out by using Origin9.0 software. For 80 concrete porous brick specimens made by the structural laboratory of Hunan University, the rebound test was carried out by using ZC3-A type concrete resilience instrument. Then, 80 groups of springback values and their corresponding compressive strength were obtained by the compressive strength test. The average rebound and compressive strength of 22 groups were divided into two groups according to the average value difference of 0.5, and the ZC4 brick resilience instrument was used. The springback test and compressive strength test of 6 standard concrete porous brick masonry specimens in the structural laboratory of Hunan University and 3 test wall pieces of Sichuan Institute of Building Sciences were carried out, and 80 sets of springback values and their corresponding compressive strength were obtained. 20 groups of average springback and average compressive strength were obtained. The experimental data obtained from the two kinds of springback instruments were regressed respectively according to the principle of least square method before and after grouping. The expression of parabola function of ZC4 type brick resilience instrument is obtained as the rebound strength measurement formula of concrete porous brick.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU522.1

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