摘要
岩相法和快速砂浆棒法试验结果表明 ,青藏铁路用混凝土中的大多数骨料含有典型的碱活性矿物。为预防混凝土日后发生碱 骨料反应 ,确保桥涵结构的长期耐久性能 ,在青藏铁路混凝土施工过程中 ,采取了限制混凝土原材料碱含量 ,严格控制混凝土的总碱量 ,掺用优质粉煤灰及DZ型专用复合外加剂等技术措施。为了考察矿物掺合料及外加剂对碱 硅酸反应的抑制效果 ,根据我国实验室实际情况 ,参照ASTMC12 6 0提出了一套实验方法。研究表明 ,复合掺入优质粉煤灰和DZ型专用复合外加剂后 ,采用该试验方法检验的结果表示抑制碱 硅酸反应有效。进一步研究发现 ,上述砂浆试件的微观结构与宏观膨胀试验结果吻合。可见 ,采用上述技术措施抑制青藏铁路混凝土碱
It was proved by ASTM C295 that most aggregates used in the concrete of Qinghai-Tibet Railway contained alkali reactive minerals. In order to prevent the alkali-silica reaction in the concrete of Qinghai-Tibet Railway and insure the long–term durability of the bridges and tunnels, measures had been taken in the course of construction, such as restricting alkali content of raw materials used in the concretes, controlling total alkali content of the concretes, adding high quality fly ash and special composite admixture of DZ in the concretes. In order to eusure the effectiveness of preventing alkali-silica reaction when mixing mineral admixture and admixture in concrete, according the situation of the laboratories in China and ASTM C1260, author raised a test method .When this method was used to evaluate the effectiveness of adding high quality fly ash and special composite admixture of DZ in the concretes of Qinghai-Tibet Railway to resist alkali-silica reaction, the measure was considered to be effective. Further study show that the macroscopical conclusion was confirmed by microcosmic test. It is obvious that mixing mineral admixture and composite additive in concrete could prevent the alkali-silica reaction efficiently.
出处
《铁道科学与工程学报》
CAS
CSCD
北大核心
2004年第2期6-13,共8页
Journal of Railway Science and Engineering
关键词
青藏铁路
铁路建设
混凝土
碱-骨料反应
青藏高原
Qinghai-Tibet railway
concrete
alkali-aggregate reaction
durability
experimental method
