Air-entraining concrete suitable for plateau areas

Abstract

The invention relates to air-entraining concrete suitable for plateau areas, and aims at effectively improving the workability and freezing resistance of the concrete in a plateau low-pressure environment, and the air-entraining concrete has the advantages of good bubble stability and high strength after hardening. The air-entraining concrete comprises the following components in parts by weight: 300-500 parts of cement; 50-100 parts of fly ash; 600-1000 parts of sand; 80-300 parts of broken stone 1 with the particle size of 5-10 mm; 160-600 parts of broken stone 2 with the particle size of 10-20 mm; 160-600 parts of broken stone 3 with the particle size of 16-31 mm; 100-200 parts of water; 1-3 parts of nano silicon dioxide; 1-2 parts of a rheological additive; 1-2 parts of an air entraining agent; 0.1-0.5 part of a bubble stabilizer; and 1-10 parts of a water reducing agent.

Description

technical field [0001] The invention relates to the technical field of building materials, in particular to an air-entraining concrete suitable for plateau areas. Background technique [0002] The plateau area has the characteristics of high altitude, thin air, low air pressure and large temperature difference. On the one hand, the annual average temperature in the plateau area is low, the daily temperature difference and annual temperature difference are large, and the number of annual freeze-thaw cycles is more than 300 times. During the day, the sun is irradiated strongly, and the temperature rises to melt the ice in the concrete, and the temperature drops at night to cause the pore water in the concrete to freeze and expand. The performance of concrete deteriorates faster under the action of strong freeze-thaw. Concrete durability is the primary issue. [0003] At present, air is mainly used to improve the frost resistance of concrete. Since the 1940s, the United Stat...

AI Technical Summary

Problems solved by technology

In this environment, the stability of the bubbles becomes worse, the lifetime of the bubbles is shortened by about 50%, the amount of air-entraining agent is doubled, and the concrete is difficult to entrain air. The air content is only about 50% under normal pressure, and the loss of air content increases by about 3 times, which greatly weakens the ability of concrete to resist freeze-thaw damage; and the concrete is easy to segregate and bleed, and the pumping resistance increases; the strength of the concrete decreases; the space coefficient of hardened concrete bubbles increases by nearly 1 times, and the average pore size increases by 8%~ 12%, the total porosity and the number of pores in the range of 500-1000nm increased significantly, and the number of air bubbles per unit volume decreased, only about 35% under normal pressure, seriously reducing the durability of concrete such as frost resistance

[0005] At present, there is a lack of basic research on the design and preparation of air-entrained concrete in plateau low-pressure environments at home and abroad.