早期高温养护对预制混凝土构件长期抗压强度的影响.pdf

生产技术
颜成华,李果,军武:早期高温养护对预制混凝土构件长期抗压强度的形响
早期高温养护对烦制混凝士构件长期抗压强度的影响
颜成华,李果2,夏军武2
(1.江苏东浦管桩有限公司,江苏连云港22246
2.中国矿业大学江苏省土木工程环境灾变与结构可靠性重点实验室,江苏徐州221115
摘要:混凝土构件的早期养护条件是决定其长期抗压强度的重要因素,为研究早期养护温度对预制混凝土
构件长期抗压强度的彩响,制作了单摻粉牒灰(SPC)、双摻粉渫灰、矿渣(DPC)和三掺粉牒灰、矿渣、硅灰
(TPC)以及对比普通水泥混凝土(OPC)试件,接照有、无预养分別进行了40℃、60℃和80℃的水养护,达
到设计强度后取出放置在室内大气环境,再分别测试其28d、100d、200d和300d龄期的抗压强度。研究
结果表明:无论普通混凝土还是矿物掺合料混凝土,早期养护温度越高,混凝土达到设计强度所需的养护
时间越短,但长期的抗压强度越低。掺加矿物掺合料和20℃的预养有助于增强混凝土抵御高温养护导致
的热应力问题,有利于预制混凝土构件长期强度的提高。
关词:矿物掺合料;预制混凝土构件;抗压强度;早期高温养护
Abstract: Initial curing condition is an important influencing factor to pre-cast concrete long-term strength.
To study the influences of initial high temperature curing on pre-cast concrete compressive strength, concrete
specimens made from fly ash concrete (SPC), fly ash and slag concrete (DPC), fly ash, slag and silica fume
concrete ( PC)and ordinary portland cement concrete(OPC)for comparison were fabricated. According to with
or without pre-curing, specimens were put into 40 C, 60C and 80 water tanks respectively for curing until
designed compressive strength reached. Then specimens were taken out and placed in an indoor natural
environment, and tested for compressive strength at 28 d, 100 d, 200 d and 300 d age periodically. Results
indicate that the higher the initial water-curing temperature is, the shorter the water-curing time is needed to
reach the designed strength, and the lower of the concrete long-term strength is. Adulteration of mineral
admixtures
(especially fly ash )and pre-curing of 20 C are beneficial for pre-cast concrete member to resist
the thermal stress problem caused by elevated temperature curing, and are liable to improve the long-term
strength
Key words: mineral admixture; concrete; compressive strength; initial high temperature curing
0引言
蒸汽养护、蒸压养护和高温水养护在混凝土预制构
混凝土的强度尤其是长期强度是决定混凝土件的生产中得到广泛的应用-。早期的高温养护
结构承载力安全的基础,而混凝土的原材料组成与可以加速水泥的水化,对火山灰质材料还可以激发
初期养护条件是决定其长期强度的重要因素。为了其活性提高其水化程度,从而提高混凝土的早期强
加快模具周转,提高混凝土预制构件的生产效率,度和致密程度?。但许多研究同时表明:早期的高
温养护温度越髙,持续时间越长,混凝土的后期强
金项目:国家自然科学基金面上项目(No.51178455),江
度下降甚至倒缩也越多。究其原因,主要为早期
苏省重点实验室开放基金项目(JSKL2012YBO1)。
的高温养护导致水泥水化产物生成和沉淀速度过
2014年5期
万方数