Research And Application On The High-performance Bearing Grouting Material

In this paper, for the construction of high-speed rail, especially high-speed rail on the request of special materials, developed an excellent technical performance, easy construction, low cost, high adaptability, the advantages of bearing grouting material.The high-performance bearings grouting material developed by this paper use rapid hardening cement as the main cementitious material, the high-quality quartz sand as fine aggregate, combined with chemical admixtures such as water reducer, retarder, expanding agent,etc.The product has good flow properties and early strength properties, the slurry has micro-expansion properties, stable performance and durability.The main research of the topics are:(1) The initial mix of the bearing grout design:Study the specific properties of mortar by the options of experimental materials and a variety of materials to changes in materials content, including the performance, strength and free expansion rate.The specific research lines are:1) Use the rapid hardening cement as the main cementitious material.2) Use high-quality quartz sand as the fine aggregate, and ratio the quartz sand of different particle size to get the best effect of close packing.3) Comparison of naphthalene, melamine and polycarboxylate superplasticizer on the fluidity, strength and expansion properties, obtained melamine superplasticizer and rapid hardening cement has good adaptability.4) Select inorganic retarder H1 as the mortar retarder, H1 can slow down the mortar of the early hydration.5) Select expansive agent combined with the departmentof lime and the other types of expansive agent, this expansive agent has significant role in promoting to the expansion of mortar.6) In the mortar mixed with small amounts of polypropylene fibers can make the mortar paste to be dispersed, to prevent bleeding and segregation, inhibition of micro-cracks.(2) The optimization of bearing grouting materials mix:According to the initial mix research, add the optimizing development components to optimize the performance of the mortar, and to study the ratio of water and temperature on various properties of mortar. The results show that:1) Optimization of components in the fluidity of mortar can make the compressive strength to meet the requirements for half an hour in advance under the requirements of fluidity, optimization components can significantly promote the growth of early compressive strength mortar, it can also increase the fluidity of mortar through time.2) Ratio of water to the mortar fluidity is obvious, when water ratio is low, mortar flow is small, with the ratio of water gradually increases, the fluidity of mortar increases too. As the ratio of water gradually increases, compressive strength with two hours of mortar decreases.3) Temperature plays a vital role in the early strength of mortar, when temperature is too low, it will inhibit the early hydration of mortar, making the low early strength of mortar. With increasing temperature, the hydration of rapid hardening cement will accelerate and significantly increase the compressive strength with two hours of mortar.(3) The construction details and engineering application of the bearing grouting material:Discuss how to respond to environmental factors on the material properties and construction problems that should be noted. Proposed the construction attention of mortar in different season, study the problems that often appear in the construction and solution. The bearing grouting material developed by this paper has been tested by laboratory and engineering, it has been popularized.