【作者】 杨旭；

【导师】 何庭蕙；

【作者基本信息】 华南理工大学 ， 固体力学， 2010， 硕士

【摘要】 液体橡胶基混凝土是以液体橡胶为基体的新型混凝土,而不同于以橡胶为填充颗粒的传统橡胶混凝土。它作为一种潜在的铺装材料,其动态力学性能非常关键,目前国内外对该材料的动态性能和损伤的研究还处于初级阶段。本文着重研究该材料的冲击和疲劳力学性能及其损伤分析,主要内容包括:(1)在大尺寸Hopkinson压杆实验系统上,对新型液体橡胶基混凝土进行了冲击试验,了解了材料的冲击性能及其材料参数的影响,考察了材料的应变率敏感性和冲击损伤特点。随着冲击速度的提高,材料具有应变率正敏感性,但到一定程度材料反而显示出应变率负敏感性。虽然在冲击后,试件尺寸基本不变,也无外观的损伤,但由冲击后测得的模量变化显示材料存在损伤,这说明新材料的冲击损伤具有不同传统混凝土材料的损伤行为和机理。(2)研究了液体橡胶基混凝土材料的弯曲疲劳性能。本文进行了液体橡胶基混凝土在不同应力水平下的三点弯曲疲劳试验,通过实验测定了材料的疲劳寿命曲线,建立了单对数形式和双对数形式的疲劳方程;基于两参数Weibull分布的疲劳寿命预测方法,得到了简化形式的存活概率函数,并通过分析疲劳实验数据,确定了不同应力水平下液体橡胶基混凝土材料的存活概率参数,得到了材料的疲劳寿命概率分布。(3)运用超声波损伤检测技术对冲击和疲劳实验中添加表面处理剂和未添加表面处理剂的液体橡胶基混凝土试件进行损伤检测分析,与冲击和疲劳实验数据分析结果进行对比,证明该方法检测混凝土损伤的准确性和实用性。同时从微观结构角度对液体橡胶基混凝土的损伤破坏机理进行分析,即考虑界面层结构和分子运动方式的影响。并通过对比实验验证了表面处理剂的添加能提高材料的疲劳和冲击性能,较好的降低材料的冲击与疲劳损伤。更多还原

【Abstract】 Liquid rubber based concrete (LRBC) is a new concrete with liquid rubber being matrix, which is different from traditional rubber concrete in which the solid rubber particles are used as all or a part of aggregates in the concrete. Being a potential pavement material, the dynamic mechanics behaviors of LRBC are very important, which are seldom studied by now. In the thesis, we focused on the properties of the dynamic and fatigue of LRBC, and the related damages analysis. The main research aspects of content include:(1) By the Spitted Hopkinson Pressure Bars system with large diameter, the LRBC was tested to learn its impact properties, including the strain rate sensitivity and impact damage, and the effects of materials parameters on the properties. With the increment of impact velocity, the new material appears positive strain rate sensitivity, but when the increment reaches a certain degree, the material shows negative strain rate sensitivity. Though the geometries of the specimen have no change and the appearances no damage after impacts, the change of the elastic modulus after impact shows that there exists the significant damage of the material, which means that the impact damages of the new material are different with that of traditional concretes and are waiting for further studies.(2) Studying on the bending fatigue properties of LRBC. In the thesis, constant-amplitude three-point bending tests under different stress levels were carried out and the fatigue life of the material is determined, single-logarithmic and double-logarithmic fatigue equation are derived. Based on the prediction method of Weibull distribution with two parameters for the fatigue life, the simple survival probability function was presented. By analyzing the experimental data of fatigue life, the Weibull parameters of fatigue life at different stress levels were obtained, and probability distributions of fatigue life were derived.3) Ultrasonic damage detection method is used to detect damages of LRBC with additive treatment and without additive treatment in impact test and fatigue test. The damages determined by the new method is compared with that from the compressive tests, the accuracy and effectiveness of this new method were verified. At the same time, the damage evolution mechanism of LRBC is analyzed by the view of microstructure which including effects of interfacial layer structure and molecular movement. Comparative tests were carried out to prove that additive treatment will increase the resistance and reduce the damage of LRBC from impact and fatigue.更多还原