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2) Water dust than influence important factor that concrete shrink, is it reduce water is it split pharmaceutical can make concrete water consumption reduce by 25% to defend to use.
3) Cement consumption important factor, concrete of person who shrink too, is it add and subtract water is it split concrete reducible 15% of the cement consumption on terms that keep the intensity of concrete of pharmaceutical to defend to mix, its volume is supplemented by increasing aggregate consumption.
4) Reduce water is it split pharmaceutical can improve consistency of grout , reduce concrete secrete ink to defend, reduce and sink and draw back deforming.
5) Improve gluing the strength of forming of the grout and aggregate, the concrete improved resists the performance of splitting.
6) Concrete is it produce stress of drawing to restrain from while shrinking, crack when drawing the stress and is greater than concrete tensile strength can produce. Reduce water is it split pharmaceutical effective concrete tensile strength of improvement very to defend , improve resisting the performance of splitting of concrete by a wide margin.
7) It can make the concrete density good to add the admixture to mix , can improve resisting carbonization of concrete effectively , reduce carbonization to shrink.
8) Is it reduce water is it split slow coagulation time proper concrete under pharmaceutical to defend , on the basis of preventing the fast water of cement from sending out heat effectively to mix, prevent the plasticity shrink that brings because the cement is not congealed for a long time from increasing.
9) Mix admixture concrete and getting easy and kind, surface easy to feel flat, form little membrane, reduce the moisture to evaporate, reduce drily and shrink. A lot of admixture all have the functions of slow coagulation, increasing and apt, improvement plasticity, the experiment that we should carry on in this respect more in the project practice is compared with and studied, than lean against not improving terms more simple, may getting simple and more direct, economy.
1.4 Early maintenance of 4 concrete
Practice has proved , the common crack of concrete , most is the surface crack of different depth, main reason its whether temperature gradient cause cold temperature of area lower too easy to form crack suddenly. So say the warm - keeping of the concrete is especially important to preventing the early crack of surface. From the viewpoint of temperature stress, should reach and require to keeping warm following:
1) Prevent concrete internal and external temperature poor and concrete surface gradient from, prevent the surface crack.
2) Prevent concrete from to be ultra and cold , should is it is it make the minimum temperature is not lower than the steady temperature of concrete service time construction time in concrete to try to try one's best.
3) Prevent the old concrete sub cooling, in order to reduce the restraint among the old and new concrete.
The early maintenance of the concrete, the main purpose lies in keeping the suitable warm and humid condition, in order to get the result of two respects, on the other hand make the concrete avoid the invasion and attack of the unfavorable and warm, humidity out of shape, the ones that prevent from harmfully are cold to contract and do to contract. On one hand make cement water function go on smoothly, is in the hope of reaching the intensity designed and resisting the ability of splitting.
The suitable warm damp condition is interrelated. Mix warm - keeping measure paid to congeal often protects wet results too. Analyze, water concrete include moisture can meet demand, cement of water have enough and to spare newly theoretically. But because the reason of evaporating etc. often causes losses of the moisture, thus postpone or hinder water of the cement from, the surface concrete receives this kind of adverse effect easiest and directly. Key period when maintained in initial a few days after so the concrete is built should pay attention to conscientiously in constructing.