Experimental Study On Self-compacting Mortar Filling Rock-fill Concrete

The rubble filled with self-compacting concrete which has high workability and goodsegregation resistance is called rock-fill concrete. The rock-fill concrete is a kind ofhigh-density concrete filled by large size stones and self-compacting concrete with smallsize aggregates. When concrete is under construction, the large size stones are put into testmode directly to constitute a large skeleton of rubble, and the self-compacting concretewith high workability and good segregation resistance are poured from the upper part ofthe skeleton. Using the good self-compacting properties of concrete, self-compactingconcrete fill the skeleton of rubble automatically under the gravity, and the mass concretewith high density, high strength, structural integrity, low shrinkage deformation and lowheat of hydration is formed.The grain size of coarse aggregate of rock-fill concrete is generally100mm or more.In order to expand the application scope of rock-fill concrete, the research focus of thispaper is how to use self-compacting mortar fill the rock-fill concrete of which the grainsize of coarse aggregate is less than100mm and give the control standard quickly andeasily.Combining results of current researches at home and abroad, the workability ofself-compacting mortar is tested by standard funnel which is used to test bulk density offine aggregate in this paper. The optimal mixing amounts of water reducer and fly ash areoptimized by cement paste fluidity test. Changing the water-cement ratio, fly ash amount,water reducer dosage, sand-cement ratio and other parameters, the effects on theworkability and strength of self-compacting mortar and the strength of rock-fill concretecaused by the parameters through the orthogonal experimental design.Results show that: the optimal ratio of self-compacting mortar is water-cement ratioof0.35, sand-cement ratio of1.3, water reducer dosage of1.6%, ash content of20%; theself-compacting mortar of which the efflux time is between80s and105s and theextension degrees is between410mm and485mm can be used for filling rock-fillconcrete; the standard funnel of bulk density test of fine aggregate can effectively detect the workability of self-compacting mortar; economic benefit of rock-fill concrete isremarkable.