高原低气压环境对新拌混凝土含气量的影响  

Effect of low-pressure in plateau environment on air content of fresh concrete

作　　者：李雪峰[1,2] 付智[1,2] 罗翥[2] 柯国炬[2] 

机构地区：[1]东南大学交通学院,南京210096 [2]交通运输部公路科学研究院,北京100088

出　　处：《东南大学学报（自然科学版）》2014年第5期1046-1051,共6页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金资助项目(51308246);交通运输部科技资助项目(201231879210)

摘　　要：通过低气压试验箱模拟高原不同海拔地区气压环境，研究了环境气压对引气剂引气能力的影响。试验结果表明：环境气压的降低将显著削弱引气剂的引气能力，当环境气压降低至50 kPa时，混凝土含气量降低约20％～49％；混凝土含气量随环境气压降低呈线性减少，初始含气量越高，随环境气压降低含气量减少速率越大；混凝土坍落度越大，其抵抗因环境气压降低造成含气量降低的能力越强。因此，在高原地区设计引气混凝土时应针对不同结构物，结合当地气压条件及引气剂类型，相较于常压情况适当增加引气剂掺量，以达到抗冻设计指标中要求的含气量。The effect of air pressure of environment on air content of fresh concrete was studied using low-pressure test chamber to stimulate the plateau environment.The experimental results indicate that the air pressure of environment has a significant impact on the performance of air-entraining agents.The air content of fresh concrete falls by roughly 20% to 49% when the air pressure is 50 kPa.The air content of fresh concrete decreases linearly with the drop of air pressure.The higher the air content of fresh concrete mixed in ordinary pressure,the faster the air content of fresh concrete decreases with the drop of air pressure.The concrete with high slump shows better resistance to drop of air-content due to low air pressure than the concrete with low slump.Therefore,in order to meet the design requirements of air content of air-entrained concrete for different constructions in the plateau regions,it is necessary to increase the dosages of air-entraining agents according to different pressure conditions and types of air-entraining agent.

关 键 词：高原 低气压 含气量 引气混凝土 

分 类 号：TU528[建筑科学—建筑技术科学]