
Refers to the concrete mass concrete structures entity is not less than the minimum size of 1m gross amount of concrete, or concrete is expected to be due to temperature changes caused by hydration of cementitious materials and contraction caused by cracks in the concrete harmful.
A large volume of concrete quality problems and major reasons:
(1) The temperature difference within the constraints of concrete tensile stress leads to concrete cracks;
(2) After cooling shrinkage of concrete, the tensile stress on the concrete outside the constraints arising cause concrete cracks;
(3) concrete itself shrinkage of concrete tensile stress causes the concrete cracks.
Second, the quality control of mass concrete indicators:
(1) pouring concrete pouring into the mold body temperature rise in temperature on the basis of not more than 50 ℃;
(2) in the form of concrete pouring body temperature not more than 25 ℃;
Cooling rate (3) not more than pouring concrete body 2.0 ℃ / d;
(4) concrete pouring surface and atmospheric temperature not more than 20 ℃.
Third, the general technique of mass concrete measures taken:
(1) reduce the mix into the mold temperature is optimized to reduce the amount of cement, concrete configuration dual mixed method (incorporation of slag and fly ash), as far as possible using low heat portland slag cement, lower heat of hydration of cement in concrete; reduce sand, stone, cement temperature; ice water mixing concrete.
(2) slow the casting speed.
(3) hierarchical placement.
(4) Select the pouring time.
(5) slow down to reduce the surface temperature (insulation cover, water conservation).
(6) puts up greenhouses.
(7) reducing the temperature of the center (using less).
(8) template insulation.
(9) the laying of the sliding layer.
(10) using the temperature monitoring technology, and timely data analysis, to take measures to guide the construction.
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