Retarded portland cement and preparation method thereof

Abstract

The invention relates to a retarded Portland cement and a preparation method thereof. The retarded Portland cement is prepared from the following components in percentage by weight: 52 to 58 percent of Portland cement clinkers, 22.2 to 25.5 percent of mixed slags, 14.8 to 17.5 percent of silica fume, and 5 percent of gypsum. The preparation method comprises the following steps of premixing a phosphorus slag, a vanadium-titanium bearing slag and a zinc slag according to the proportion to obtain a mixed slag a; mixing and grinding the mixed slag a, the Portland cement clinkers, the silica fume and the gypsum to prepare the retarded Portland cement. According to the retarded Portland cement provided by the invention, the usage amount of the Portland cement clinkers is reduced, so that the ingredient cost of producing the cement is effectively reduced, and the discharge of carbon dioxide is reduced; meanwhile, with the adding of the phosphorus slag and the silica fume, the problem that the long-term strength is reduced since the Portland cement clinkers are reduced is solved. The defects that the setting time is prolonged and the strength is reduced, or the strength is increased and the setting time is shorter due to the utilization of other materials in the prior art are overcome, and the obtained retarded Portland cement is remarkably prolonged in initial setting time and remarkably improved in long-term strength.

Description

technical field [0001] The invention relates to a retarded Portland cement and a preparation method thereof, in particular to a retarded Portland cement mixed with microsilica fume and phosphorus slag and a preparation method thereof. Background technique [0002] Cement is used to stabilize sand and gravel (including gravel soil) and crushed stone in construction engineering, and is an indispensable engineering basic material. Under some special construction conditions, cement also needs to have some corresponding specific properties, such as mass concrete, long-distance transportation, summer high-temperature construction and other conditions, due to the long time for construction mixing, paving, and compaction, it must be Prolong the initial setting time of cement, so according to the construction time, the initial setting time should be around 300 minutes, and the final setting time should not exceed 600 minutes. At present, there are generally two methods in the produc...

AI Technical Summary

Problems solved by technology

Phosphorus slag can be widely used in cement-based materials, and has the characteristics of low heat of hydration, good durability, and high later strength. However, cement-based materials only mixed with phosphorus slag can prolong the setting time, but at the same time have low early strength. , and drying shrinkage problems

[0005] Existing Chinese Patent Document 1 "A Phosphorous Slag Super Sulfate Cement and Its Preparation Method" (Patent No. ZL201210408576.2), and Existing Chinese Patent Application Document 2 "A Silica Waste Rock Cement Mixture" (Patent Application No. 201410520857.6 ) respectively disclosed the use of phosphorus slag to prepare phosphorus slag super sulfate cement, and the use of silica fume to prepare cement admixtures, but the resulting cement still has the problem of low early strength or short setting time

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