A kind of recycled micropowder cement and preparation method thereof

Abstract

The invention discloses a regenerated micropowder cement and a preparation method thereof. The regenerated micropowder cement of the present invention comprises the following components in mass percentage: compound regenerated micropowder: 35%-55%; cement clinker powder: 40%-60%; gypsum powder: 2%-5%; The micropowder is compounded by 5 kinds of regenerated micropowder with different particle size ranges, and the regenerated micropowder does not need to be activated. The preparation method of the regenerated micropowder cement of the present invention comprises the following steps: mixing the compound regenerated micropowder, the cement clinker powder and the gypsum powder uniformly to obtain the regenerated micropowder cement. In the present invention, regenerated micropowder with different particle size ranges is used for composite cement, and the amount of regenerated micropowder is large, and the prepared regenerated micropowder cement has excellent performance, strength grade ≥42.5, 28-day compressive strength> 40MPa, 28-day flexural strength> 6MPa.

Description

technical field [0001] The invention relates to the technical field of building materials, in particular to a regenerated micropowder cement and a preparation method thereof. Background technique [0002] With the advancement of urbanization, a large number of old buildings need to be demolished, which will generate a large amount of construction waste. The data shows that every new 1m 2 of buildings and every 1m of demolition 2 of old buildings will generate 0.3 tons and 1.3 tons of construction waste respectively, of which about 50% is waste concrete. At present, the waste concrete is mainly crushed and screened into recycled coarse aggregate and recycled fine aggregate to realize its resource utilization, and the preparation process of recycled coarse and fine aggregate will produce about 20% to 35% of the recycled content. Micropowder and regenerated micropowder have not been used efficiently, resulting in a serious waste of resources. [0003] The particles of recyc...

AI Technical Summary

Problems solved by technology

At present, waste concrete is mainly crushed and screened to make recycled coarse aggregate and recycled fine aggregate to realize its resource utilization, and the preparation process of recycled coarse and fine aggregate will produce about 20% to 35% recycled Micropowder, recycled micropowder has not been efficiently utilized, resulting in serious waste of resources

[0003] The particles of recycled micropowder are small and require a lot of water. When used in cement-based materials, it is easy to cause poor performance of freshly mixed concrete or mortar, increased loss of fluidity, and reduced strength of hardened concrete or mortar. The application is greatly restricted.

Moreover, if the regenerated micropowder is directly mixed into cement or only ground to a certain fineness and then compounded with cement clinker, fly ash, slag and other cementitious materials, the performance of the composite cement will be greatly reduced, and it is difficult to produce strength grades. Composite cement above 42.5, and the content of recycled micropowder is very low (usually no more than 15%), and it is impossible to realize large quantities and efficient utilization of recycled micropowder

In order to improve the utilization rate of recycled micropowder, at present, it is mainly activated by means of high-temperature calcination, carbonization, chemical excitation, etc., so that the 28d compressive strength of recycled micropowder cement can reach 45.0MPa, but even after activation, the recycled micropowder is still in the composite The dosage in cement is still lower than 30%, and it is still difficult to realize the utilization of large dosage. Moreover, the activation treatment of recycled micropowder will also increase the production cost of composite cement

Images