Application Of Collecting Dust Powder In Concrete

Collecting dust powder is a kind of powder that is produced during building stone production,collected and stored through the dust collection system.The mechanical properties of concrete incorporated collecting dust powder as mineral admixtures and the sulfate resistance of collecting dust powder cement at low temperature were investigated,and the phase components of sulfate attack were characterized by XRD and FTIR,which will provide the technical basis for applications of collecting dust powder as admixtures in the concrete.The results indicate as follow:With the collecting dust powder increasing,the strength of cement mortars decreased continuously.Fly ash is replaced by collecting dust powder with equal volume or equal quality to prepared C30 and C50 concrete,with the increase of collecting dust powder replacement ratio,the loss of concrete slump flow and slump after one hour is smaller and the compressive strength is firstly increased and then decreased.The collecting dust powder cement is susceptible to thaumasite sulfate attack(TSA).The ratio of collecting dust powder in cement is increased and the age of exposed to 5% MgSO4 solution attack is prolonged,the deteriorated of TSA is more serious.Fly ash can improve sulfate resistance of collecting dust powder cement at low temperature.The suitable percent contents of fly ash and collecting dust powder respectively is 15%.The lower ratio of water and cement(w/c)can improve strength and sulfate resistance of collecting dust powder cement at low temperature,and specimens with w/c for 0.3 exposed to 5% MgSO4 solution attack for 270 d are not deteriorated by TSA.The water proofing agent added in collecting dust powder cement can improve sulfate resistance.The compression strength of cement firstly increased and then decreased with the increase of water proofing agent,and the suitable dosage is 1.8%.The collecting dust powder as admixture is suitable for concrete engineering,which is low cost.