Study on proportioning test of a new cementing filling material and hydration mechanism

Abstract

The strength of the new filling cementing material which is mixed by fly ash, lime, desulfurization gypsum and a small amount of cement is tested in order to apply to backfill mining in Xinyang coal mine.The optimum ratio of cement, lime, desulfurization gypsum and fly ash in coal mine is determined by orthogonal test method.Hydration mechanism of new filling materials is studied by the XRD and electron microscope scanning(SEM).The types of hydration products and the micro development form of cementitious materials at different ages are revealed.Finally a new type of backfilling cementing material is invented by mixing cementitious materials, coal and water and it's characteristics is compared with previous version.The results show that the best ratio of new cementing material for coal mine is Cement:Lime:Desulfurization gypsum:Fly ash=10%:1.8%:9%:79.2%;The main presence of hydration products is needle, linked through flocculent filamentous product when the curing age of the new cementing material is 3 days;The main forms of the hydration products are clusters, blocks or patches, and hydration products were closely bonded when the curing period reached 28 days;It was found that the new filling material can greatly reduce the cost of the cementitious material and apply to the requirement of filling mining in the Xinyang coal mine despite the intensity and bleeding rate and other indicators decreased slightly through comparing new type of backfilling cementing material with the high concentration of cemented filling materials at the same concentration.

Keywords

• new filling cementing material
• orthogonal test
• hydration products
• micro structure
• high concentration cementation stowing materials