The Experimental Study Based On The Ordinary Portland Cement- Aluminate Cement- Gypsum Cementitious System

Ordinary Portland cement, aluminate cement and gypsum, mixed by a certain percentage, can be compounded into mortar or concrete due to the good performance of rapid hardening and high strength, which can be applied to structural anchoring, equipment foundation foot grout, retention and engineering repair and so on. This paper according to the study of the Ordinary Portland cement- aluminate cement-gypsum system, to provide the basis for repairing materials which have the proportions of rapid hardening, early strength and easy for construction.In this paper, the best ratio of ternary cementitious system was determined. Moreover, the effects of admixtures on the properties of ternary cementitious system were studied by mixing the superplasticizer and retarder. Finally, it was supposed to enhance the strength of the ternary cementitious materials by adding steel fibers. The main experiments conducted in this paper include the setting time, fluidity and adsorption capacity of the ternary cementitious paste, as well as the compressive strength, flexural strength, tensile splitting strength of the mortar and concrete. Meanwhile, the X-diffraction analyzer and scanning electron microscope was used to test the micorscopic characterization of the samples.The results are described as follows:(1) The best ratio of Ordinary Portland cement- aluminate cement- gypsum system was 76%∶16%∶8%.(2) The ternary cementitious has longer setting time when the superplasticizer mixed with retarder.(3) With the increaseing of dosage of retarder, the fluidity of the ternary cementitious paste increased at first and then decreased. Notably, the maximum fluidity appears when the content of the retarders reaches 0.09%.(4) When the superplasticizer mixed with retarder, the early strength is reduced with the dosage of retarder, and the later strength of the motar improved by the retarder. At the same time, the negative influence of citric acid(CA) is smaller than that of sodium gluconate(SG).(5) Bow steel fibers have a certain enhancement on compressive strength, flexural strength and tensile splitting strength of concrete. The optimum amount of steel fibers in the ternary cementitious system motar is 2.0%. Meanwhile, when the content of steel fiber reaches 0.68%, strongest effect will show in the properties of the ternary cementitious system concrete.