粗骨料体积分数对混凝土弹模和抗压强度的影响  

Effect of volume fraction of coarse aggregate on elastic modulus and compressive strength of concrete

作　　者：韩宇栋[1,2] 张君[1,2] 王振波[1,2] 

机构地区：[1]清华大学土木工程系,北京100084 [2]清华大学结构安全与耐久教育部重点实验室,北京100084

出　　处：《哈尔滨工业大学学报》2013年第4期84-91,共8页Journal of Harbin Institute of Technology

基　　金：国家自然科学基金(51178248);国家重点基础研究发展计划(973计划)(2009CB623200);高等学校博士学科点专项科研基金(20100002110016)

摘　　要：为了研究粗骨料体积分数对早龄期混凝土弹性模量和轴心抗压强度发展的影响,本文针对水胶比为0.62、0.43和0.3的三种混凝土分别设计了粗骨料体积分数逐渐增大的系列混凝土配合比.保持混凝土的砂浆各组分不变,粗骨料体积分数从零逐渐增大,同一水胶比的系列混凝土28 d静力抗压弹性模量随粗骨料体积分数增大而单调显著增大,而其轴心抗压强度则呈现"先减小、后增大"的变化规律且变化趋势相对平缓.环境干燥下混凝土内部可蒸发水散失将降低水泥水化程度,混凝土的弹性模量和轴心抗压强度均低于密封养护下的同期值;水胶比越大,环境干燥的影响越大.本研究建议的基于水泥水化度发展预测混凝土弹性模量和抗压强度的模型,对不同水胶比、不同粗骨料体积分数、不同养护条件均适用,试验值和模型值吻合良好.To investigate the effect of volume fraction of coarse aggregate （VFCA） on the developments of elastic modulus and prismatic compressive strength of early-age concrete, mixtures with different VFCA were designed for concretes with water to cementitious material ratio （w/b） of 0.62, O. 43 and 0.3 respectively. Keeping the mortar composition and w/b unchanged, and merely increasing the VFCA gradually from zero, the elastic modulus of concrete at the age of 28 days increased significantly, whereas the compressive strength of prismatic specimen first slightly decreased when VFCA is small, and subsequently increased gently when VFCA became larger. External drying induced evaporable water loss in concrete decreased the degree of cement hydration, which resulted in a reduction on elastic modulus, and a reduction on compressive strength as well in the dried specimens compared to that of sealed ones with the same curing age. The larger the w/b was, the bigger reduction the elastic modulus exhibited. Degree of cement hydration-based predictions of concrete elastic modulus and compressive strength were proposed, and good agreements were found between the test and the analytical results regardless of w/b, VFCA and curing conditions

关 键 词：混凝土 粗骨料体积分数 弹性模量 轴心抗压强度 水泥水化度 

分 类 号：TU528[建筑科学—建筑技术科学]