摘要
以混凝土冻融耐久性为研究内容,用不同种类混凝土的抗压强度、动弹性模量、超声波声速等指标的损失率来表征冻融过程中混凝土的性能劣化状况,并系统比较了不同种类混凝土的抗冻性优劣.通过研究得出:无论是普通混凝土,还是高强混凝土或高性能混凝土,其动弹模损失率、抗压强度损失率、超声波声速损失率均随冻融次数的增加而增大;提高混凝土强度在一定程度上可以提高混凝土抗冻融性能;掺入高效减水剂、优质引气剂和优质掺合料等,高性能混凝土抗冻融性能比对应的基准混凝土性能显著改善,而且通过这样的技术措施,较低强度等级的混凝土也可以获得高抗冻性.鉴于超声波测试方法方便、快捷、准确,而且可以直接用于实际工程的混凝土性能检测,所以,与动弹模测试方法相比,采用超声波测试技术来评价实际工程中混凝土的耐久性劣化程度具有明显的优势.
The paper deals with the freeze-thaw durability of concrete, describing the property degradation in freezing and thawing of different kinds of concrete with their loss rate of such indexes as compressive strength, dynamic modulus of elastic and ultrasonic wave velocity, and then systemically comparing their performance of frost resistance. Experimental results showed that not only to ordinary concrete but also to high strength concrete and high performance concrete, the loss rate of dynamic modulus of elasticity, of compressive strength and that of ultrasonic wave velocity always increased with the increase of number of freezing-thawing cycles. It also demonstrated that we could enhance the freezing-thawing durability by heightening the strength of concrete in some degree. In fact, on the one hand, the freezing-thawing durability of high performance concrete mixed in high efficient water reducer, high-quality air-entrance agent and high-quality admixture has been improved greatly compared with that of normal concrete. On the other hand, through the above technical measures, concrete with low strength can as well get a high frost resistance. Besides, the testing method of ultrasonic wave is so convenient, prompt and accurate and can be utilized to test the performance of concrete in practical engineering. Therefore, using the descriptive method to evaluate the durability of concrete in practical engineering has obvious advantages over using the method of dynamic modulus of elastics.
出处
《湖南城市学院学报》
2003年第6期1-5,共5页
Journal of Hunan City Univeristy
基金
国家自然科学基金资助项目(50278039).
关键词
混凝土
冻融耐久性
超声波
抗压强度
动弹性模量
concrete
durability
freeze- thaw
ultrasonic wave
dynamic modulus of elasticity
