板状砂岩粗骨料应用于铁路100年耐久性泵送混凝土

APPLICATION OF PLATE SANDSTONE COARSE AGGREGATE IN RAILWAY 100 YEAR DURABILITY PUMPING CONCRETE

板状砂岩粗骨料能否应用于铁路100年耐久性泵送混凝土中,需重点解决如何降低单方混凝土用水量和改善混凝土和易性,是否满足力学及耐久性能要求,是否有足够的经济性等3个问题。采用粗骨料粒形改善及级配优化、提高聚羧酸减水剂缓凝效果和减水剂掺量、适当提高混凝土单方用水量、根据不同环境等级适当提高粉煤灰掺量、适当提高混凝土含气量和引气质量等方式可,改善板状砂岩粗骨料混凝土的和易性。配制的板状砂岩粗骨料混凝土配合比,在非冻融破坏环境地区,其力学及耐久性能可满足铁路100年使用要求。在富砂岩地区,砂岩粗骨料混凝土的经济性大幅度优于石灰岩。

It is necessary to solve the following three problems:how to reduce the water consumption of the single square concrete and improve the workability of the concrete,whether it satisfies the mechanical and durability requirements,and whether it has enough economy,whether the coarse aggregate of the plate sandstone can be applied to the 100 year durable pump concrete of the railway.The experimental study shows that the coarse aggregate grain shape improvement and the optimization of gradation,the improvement of the retarding effect of polycarboxylic water reducing agent and the amount of water reducing agent,the proper increase of the water consumption of concrete,the appropriate increase of the amount of fly ash according to the different environmental grades,the proper improvement of the gas content and the quality of the air entraining can be improved.The workability of aggregate concrete is verified by further test.It is proved that the mixture ratio of coarse aggregate concrete of plate like sandstone,in the area of non freezing and thawing environment,its mechanical and durability can meet the requirements of the 100 year use of railway,and the economy of sandstone coarse aggregate concrete is much better than that of limestone.