摘要
为评定早期冻融损伤对混凝土结构服役期承载性能及耐久性能的影响规律,通过不同掺合料种类及掺量、不同起冻时刻的混凝土早期受冻试验,对比了不同受冻时刻混凝土服役期的表面损伤形态,研究了起冻时刻、掺合料掺量对早期受冻混凝土服役期抗压强度、劈拉强度、动弹性模量、渗透性的影响规律,探讨了早期受冻对混凝土服役性能的损伤机理。结果表明:起冻时刻对混凝土抗压强度、劈拉强度、动弹模的影响程度均表现为2h>0.5h≈8h>1d>3d,劈拉强度损失最明显,动弹模损失次之,抗压强度损失最不显著;掺入20%粉煤灰或15%矿粉或20%煤矸石的混凝土早期受冻后的强度和动弹模损失最小,略小于普通混凝土;随着掺合料掺量的增加,同时刻受冻混凝土试件的抗渗水性和抗渗气性变差;未冻混凝土试件的抗渗性最好,3d受冻试件次之,1d受冻试件再次,而0.5、2、8h受冻试件最差甚至超出AutoClam设备的测试范围。
In order to evaluate the influence rules of early frost damage on the bearing property and durability of concrete structure in service period,early frost experiments considering different admixtures and different freezing times were carried out.The surface damage forms of different freezing times were compared.The influence rules of freezing times and mineral admixtures on compressive strength,splitting tensile strength,dynamic elastic modulus and permeability of early frost admixture concrete were studied.The damage mechanism of early frost on service performance was discussed.The results showed that the damage degree of freezing time on compressive strength,splitting tensile strength and dynamic elastic modulus embodied as 2h〉0.5h≈8h〉1d〉3d.The most obvious loss was the splitting tensile strength,and the next was the dynamic elastic modulus.The least loss was the compressive strength.When 20%fly ash or 15% slag or 20% coal gangue was incorporated into concrete,the strength loss and the dynamic elastic modulus loss was the smallest and smaller than that of common concrete.With the increase of admixture,the anti-water-permeability and anti-air-penetration of concrete specimen at same freezing timewere worsen.The anti-permeability of unfrozen concrete was the best,and the next is 3-day frozen concrete.The third is 1-day frozen concrete,and the anti-permeability of 0.5-hour frozen and 2-hour frozen and 8-hour frozen concrete were the worst and even beyond the test range of AutoClam equipment.
出处
《土木建筑与环境工程》
CSCD
北大核心
2017年第5期93-99,共7页
Journal of Civil,Architectural & Environment Engineering
基金
国家自然科学基金(51308441
51678473)
陕西省自然科学基础研究计划(2016JM5073)~~
作者简介
胡晓鹏（1980-）,男,博士,副教授,主要从事混凝土结构耐久性能研究,（E-mail）shs339@sina.com.
