The Study On Performance Of Mortar Of The Basin Rubber Bearing Of High Speed Railway

In recent years, the focusing of railway construction is on the high- speed railway in our own country. The characteristics of high-speed railway are fast speed, safe and convenient which require higher performance of its base material. Most of the current domestic research are on the performance of mortar for cast-in-place bridge pot rubber bearing. However, the research on the mortar specialized in precast beam pot rubber bearing is a lack of systematic study.As the mortar specialized in the basin rubber bearing of high speed railway have the requirements of the rapid harden high-strength on the early hydration. Firstly, this paper studies the influence of different sand grain composition to the mortar, this paper selected is the combinations of 8~20mesh, 20~40mesh, 40~70mesh, 70~140mesh. Secondly, the research accelerator, retarders, superplasticizer, thickening agent and coagulant factors of single affecting on workability and mechanical properties of mortar. Effect on performance of mortar with multivariate admixtures including accelerator, thickening agent, superplasticizer and retarders. Finally,the optimum set of hydration heat and XRD experiments.The results show:(1)8~20 mesh sand greatest influence on the mechanical properties of mortar, when the single cube dosage of 8~20 mesh、20~40 mesh、40~70 mesh、70~140 mesh of sand are 325kg/t、 75kg/t、75kg/t、50kg/t, the mortar shows better strength properties.(2) Accelerator can improve the early strength mortar and reduce late strength; Retarder can extend the setting time of mortar. Compressive strength of mortar decreased slightly,mortar strength of 12 h and 24 h improved significantly, when content is 0.10%,mortar compressive strength of 24 h increased by 22%;Superplasticizer incorporated that mortar still has a large fluidity at 30 min.Mortar early strength increase by superplasticizer dosage increased.With the increase of dosage of coagulant mortar’s early compressive strength increase first and then decrease, Its late strength increases too. The optimal dosage of thickener MC400 is 0.2 kg/t ~ 0.6 kg/t.(3) Variance analysis showed that accelerator is influence of the most significant sector of influence on compressive strength of mortar 8h and late shrinkage of mortar, Thickener is influence of the most significant sector of influence on 24 h flexural strength of mortar and compressive strength of the 12 h, Superplasticizer is the most significant sector of influence on late compressive strength and early shrinkage of mortar. Retarder is the most significant sector of influenceon compressive strength of mortar.(4)The addition of admixture to the made the hydration heat increase. The second exothermic peak disappears in the process of hydration that its first hydration exothermic peak appears 30 min later. When the hydration goes 2h, the content of anhydrous calcium sulfo-aluminate increased, and at the same time generated plenty of Ettringite. With the extension of the mortar hydration age, the content of the anhydrous calcium sulfo-aluminate decreased, while the content of the Ettringite continues to increase.