Views: 9 Author: Mary Publish Time: 2019-06-12 Origin: Horizon Chemical
1. Mix Ratio Adjustment
According to the construction environment, the summer construction mix proportion should be adjusted reasonably. In order to reduce the loss of concrete slump and avoid the concentration of hydration heat, the cement with lower hydration heat can be used as raw materials, and the setting time of concrete can be delayed by adjusting the amount of compound admixtures to meet the construction requirements.
2. Concrete pouring in summer
When pouring concrete in hot climate, we should adjust the time, properly arrange the construction work surface, in night or morning with lower ambient temperature to carry out concrete construction, avoid the high temperature time in noon or afternoon, equip enough manpower, equipment and machinery to cope with the disadvantageous situation that concrete, and control the temperature difference between concrete surface and the outside and concrete temperature difference between interior and surface.
(1)To strengthen temperature observation in construction, pay attention to temperature management. If the actual temperature difference can be controlled less than the allowable value in construction, temperature cracks can be avoided. Temperature management is based on timely and accurate temperature observation. At present, there are many methods to measure the internal temperature of concrete, such as resistance type, thermocouple type and bar type, alcohol, thermometer and so on.
(2) Take appropriate temperature control measures in concrete pouring process, the actual measured temperature difference should be less than the allowable temperature difference. The main measures adopted are: reducing pouring temperature, paying attention to aggregate sunscreen, adding ice chips or ice water to mix concrete in concrete construction, adding caps to containers in transportation to prevent sunshine; reducing the temperature rise of hydration heat, mainly through the selection of reasonable raw materials. In order to prevent surface cracks, measures can be taken to increase the surface temperature of concrete, such as covering thermal insulation on the exposed surface of concrete structure, setting up thermal insulation shed and covering plastic film.
(3) In order to reduce the maximum temperature of concrete, cooling water pipes (serpentine pipes) can be embedded in the structure to cool the mass concrete by circulating water. The maximum temperature of concrete embedded with cooling water pipe can be reduced by 4 to 6 degrees Celsius.
(4) In the construction, the use of fly ash with a large ratio of bottom water to binder not only meets the strength requirements, but also makes the whole continuous casting successful and ensures the construction quality. The temperature difference between inside and outside of block concrete is always lower than 20 C, effectively controlling the cracks.