高瓦斯隧道混凝土气密性能试验研究  

Experimental Study on Air Tightness of Concrete Used in High Gas Tunnel

作　　者：王秀芬[1] 

机构地区：[1]中铁十二局集团有限公司,太原030024

出　　处：《铁道工程学报》2013年第5期75-81,共7页Journal of Railway Engineering Society

摘　　要：研究目的:结合达成铁路天台寺隧道施工实际,对高瓦斯隧道气密性混凝土的气密性能进行系统的试验研究,找出混凝土气密性能的影响因素及影响规律,为气密性混凝土的配制与施工控制提供技术参数。研究结论:(1)气密性混凝土的水胶比小于0.4为宜,不得超过0.45;(2)细骨料的含泥量不超过2.5%,粗骨料最大粒径不宜超过40 mm;(3)粗骨料要严格控制针片状含量,砂率大于36%为宜且在条件允许的情况下尽可能选择较大的砂率;(4)气密性混凝土单方胶凝材料不宜小于380 kg;(5)掺硅灰和粉煤灰有利于提高混凝土的气密性;(6)减水剂和密实剂可以提高混凝土的气密性,在有多种外加剂时,要通过试验来确定各种外加剂的适应性问题,争取做到二者相互适应,以达到气密性最好;(7)粉煤灰和硅灰的掺入使得水泥产物C-S-H碱度降低,密实度增加,改善了骨料界面CH的定向排列和孔隙减少,不仅降低了钙矾石的生成,还提高了混凝土的气密性能;(8)研究成果可应用于瓦斯隧道气密性混凝土配制与施工。Research purposes： Combined with construction of the Tiantaisi Tunnel of the Dazhou - Chengdu Railway, the experimental study was done on the air tightness of the concrete used for the high gas tunnel to find the influence factors and influence law on the concrete gas tightness for providing the technical parameters for making up the gas - tightness concrete and its appliable control in high gas tunnel construction. Research conclusions： （ 1 ） The water - binder ratio of the air - tightness concrete should be less than 0.4, no bigger than 0.45. （ 2 ） The silt content of the fine aggregate should be not more than 2.5 %. The silt content of the coarse aggregate should not be more than 40 mm, with maximum grain size of no more than 40 mm. （3）The elongated flaky particle content of the coarse aggregate should be strictly controlled, and the ratio of the sand and the aggregate should be more than 36% , and the ratio of the sand and the aggregate should be big as much as possible if allowable. （4）The binder content of the air- tightness concrete should be more than 380 kg for 1 m3 concrete. （5）The silica fume and fly ash are good for improving the air tightness of the concrete. （ 6 ） The water reducer and compacting agent are able to improve the air tightness of concrete. When many additives have to be used, their adaptabilities should be tested to make them adaptable each other for obtaining the best air tightness. （7）The C - S - H alkalinity of the cement hydration product can be decreased and compactness can be increased by using silica fume and fly ash. In this way, the directional arrangement of Ca （OH）2 at the aggregate interface can be improved, the production of ettringite can be reduced and the air tightness of concrete can be enhanced. （8）The research results can be used in preparation and construction of air tightness of concrete for the gas tunnel.

关 键 词：高瓦斯隧道 混凝土 气密性 试验研究 

分 类 号：TU528[建筑科学—建筑技术科学]