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Gypsum is an excellent gelling material, its performance is far superior to some of the natural gypsum, is the best alternative to natural gypsum; slag because it contains a certain amount of cementitious mineral, it has a gelling . Gypsum-based gypsum slag cementitious materials as the substrate, steel slag to fill the body, the material takes advantage of two kinds of \However, due to the formation of slag condition is complex, cementitious mineral content less difficult hydration; Gypsum also has a high moisture, marked thickening water consumption, particle size distribution and poor performance deficiencies, making these two plastic hardening materials can not get a good application. Therefore, in order to make better use of both cementitious materials, mainly from the addition of activators, retarders, water reducer, etc. to improve the gypsum-based slag cementitious material. This paper discusses the steel slag cementitious materials on mechanical properties, such as setting time and crystal morphology performance, determine the gypsum-based slag cementitious materials in the amount of slag. Through experimental study found that steel slag as cementitious material 15% of the total mass, the mechanical properties of cementitious materials, setting time and hardened crystal morphology have shown a more excellent performance. In this paper, different single doped activator, mixed activator complex are two ways to stimulate the potential activity slag, gypsum-based slag thus improving the performance of cementitious materials. Found that a variety of different levels of activator can stimulate the potential activity of the slag, to improve the mechanical properties of cementitious materials, increase the hydration products of cementitious material is cured body of content, but will shorten the setting time of cementitious materials. Through analysis of SEM images can be obtained with the XRD patterns, body hardening cementitious material mainly calcium sulfate dihydrate crystals, CSH gel, AFt, AFm based. Obtained by orthogonal experiment, the 8th activator (cement clinker content is 2%, 0.8% triethanolamine dosage, dosage of 3% aluminum sulfate, sodium silicate content is 0.2%) can effectively improve gum condensate material surface efflorescence phenomenon, improve the mechanical properties of cementitious materials. Curing also affect the performance of cementitious materials is an important factor, research shows that the best way for the Conservation of Nature Conservation (temperature: 20 ± 2 ℃ Humidity: 40% -50%). Experimental study of sodium tripolyphosphate, tartaric, citric three kinds of retarders on the role of setting time cementitious materials studied. Study found that three kinds of retarders can play a retarding effect, but the mechanical properties of cementitious materials will have a negative impact. Citric acid, tartaric acid and the cementitious material in the liquid phase to form complexes with calcium ions, covering the surface of the gypsum embryos, reducing surface active nucleus, increasing the nucleation barrier, the gypsum crystal reduce the number of nuclear, further delaying the hydration of cementitious materials; sodium tripolyphosphate and gypsum to form a precipitate film deposited on hemihydrate gypsum and gypsum nucleation surface, hindering the dissolution of gypsum hemihydrate, delayed nuclei formation. Amount of superplasticizer can improve water reduction of cementitious materials, but excessive dosage, water-reducing effect is no longer significant, and the mechanical properties of cementitious materials would adversely affect, FDN polycarboxylate water reducing effect was less poor water reducing agent. Superplasticizer water reducing effect mainly through electrostatic repulsion and steric effects achieved, which polycarboxylate superplasticizer mainly through two effects together to complete, while the FDN superplasticizer is through electrostatic repulsion effect complete. The mixing water retaining agent generally reduces early strength cementitious material, increasing the content of hardened needle-like crystals in vivo, to extend the hydration of cementitious materials, time, but carboxymethyl cellulose, methyl cellulose, water is better than the effect of differential . Methylcellulose slag cementitious materials for gypsum-based effects, mainly in three aspects, first thickening, thickening effect, two is to enhance the role of Third retains water; carboxymethyl cellulose cementitious materials The major impact on the role of water and retarding effect.
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