The Experimental Study On Properties Of Portland Cement-Sulphoaluminate Cement Composite System

At present,there are many researches on the mixing of Portland cement and sulphoaluminate cement.Previous studies have shown that the two kinds of cement can not only play their respective advantages,but also shorten the coagulation time.However,the research was limited to two kinds of cements mixing.The influence of mineral admixtures on two kinds of cement composite system has not been further explored.Mineral admixture can not only improve the performance of Portland cement sulphoaluminate cement,but also save environment and reduce costs.This paper studies the Portland cement,polycarboxylate superplasticizer and mineral admixtures on Portland cement-sulphur aluminate cement standard consistency water consumption,setting time,flexural and compressive strength of colloidal mortar shrinkage rate and the influence of hydration heat?supplemented by XRD and SEM analysis,come to the conclusion:(1)Adding Portland cement to sulphoaluminate cement will increase the water consumption of standard consistency.When the Portland cement content is reducing,the setting time will decrease,and vice versa.The polycarboxylate superplasticizer will reduce the water consumption of standard consistency and shorten the setting time.When the amount of water reducer is 1%?the water consumption of standard consistency is the minimum and the setting time is the shortest.With the increase of mineral admixture,the water consumption of standard consistency will increase gradually,and the setting time will gradually extend.(2)Two kinds of cement mixed will reduce the strength;The mixing of polycarboxylate superplasticizer increases the strength of the gel,and the maximum strength is when the content is 1.0%.The mineral admixture has been used to reduce the strength of the sand.In addition,the strength of the test parts of the mineral powder is the lowest,and the 3 days can increase the strength of compressive strength by 3 days.(3)Sulphoaluminate cement and Portland cement mixed can improve the drying shrinkage of mortar;polycarboxylate superplasticizer can improve the drying shrinkage of mortar,content greater than 1.2%,the shrinkage rate increased;slag and fly ash admixture can weaken the mortar dry shrinkage parts,including slag powder and fly ash 30%20%when the dry shrinkage rate lowest,silica fume will make the dry shrinkage of mortar.(4)Two kinds of cement mixed and unable to produce new products,the early hydration rate slowed down,but in advance,the total heat release is reduced;adding water reducing agent to hydration products increased,the hydration exothermic peak early time gradually postponed,but the early hydration rate,hydration heat difference in general,only the dosage of 1%,the total heat release;slag and silica fume,the initial hydration rate,hydration exothermic peak time delay,the total hydration heat is reduced;the addition of fly ash,the initial hydration rate,hydration heat peak time later,the total heat of hydration at the age of fly ash decreased.The addition of mineral admixtures reduces the hydration products.(5)The addition of mineral admixture will improve the anti-sulphate corrosion resistance of rubber sand samples and improve the ability to resist erosion with the increase of the amount of mixing.Among them,the anti-sulphate capability of the powder is the best.