(1) easy to secrete large cement fineness water, cement C3A content is low and easy bleeding, cement standard consistency small amount of water, and easy bleeding.
(2)the amount of cement is small, easy bleeding.
(3) low-grade cement ratio of high-grade cement concrete and easy bleeding (with content).
(4) the same level of concrete, concrete high-grade cement than low-grade cement concrete more bleeding.
(5) units of water is too large concrete easily bleeding, segregation.
(6) Concrete mixture temperature is too high, especially in summer, the temperature is high, quick hydration, large slump loss.
(7) the intensity of low-grade concrete prone to bleeding.
(8) The rate of small concrete sand and easy bleeding, segregation phenomenon.
(9) continuous particle size smaller water than the single particle size gravel gravel concrete bleeding.
(10) concrete admixture water retention, thickening, poor air-entraining concrete prone to bleeding.
(11) excess concrete mixer concrete admixtures prone to bleeding, segregation.
(12) Some models of the mixer truck was stirred poor performance by some distance transport, when the initial discharge concrete mixtures obvious coarse aggregate floating phenomenon.
(13) concrete mixer truck mix leave water barrel, not drained before loading or during transport, any water to mix barrel.
2. Solutions
(1) the fundamental way is to reduce the unit water consumption.
(2) increasing the rate of sand, choose a reasonable rate of sand.
(3) hot summer, to take measures to reduce the temperature of the concrete mixture.
(4) increasing the amount of cement or mixed with the right amount of Ⅰ, Ⅱ grade fly ash.
(5) continuous grading of gravel and small flakiness content.
(6) to improve the performance of concrete admixtures, it has better water retention, thickening, or the amount of reducing concrete admixture content (live only), mixing station if the lower dosage of concrete admixtures, may be out of concrete and concrete Slump loss fast new problems.
(7) concrete mixer truck in front of the discharge, should be in high-speed rotating mixing drum, the concrete mixture evenly discharge.
(8) to strengthen the management of the truck after cleaning the mixing tube shall discharge before charging after draining them. After loading, non-random to mix with water barrel.
3. Lessons Learned
Bleeding, segregation problem prone against concrete. By learning experimented summed up a set with the actual situation to solve problems. Such as optimizing mix, strengthen the approach detection of raw materials, enhance on-site management. Prevent mixing station due to poor site management and increased water consumption random phenomenon.
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