The use of concrete admixtures can not only improve work efficiency and increase economic benefits, it has a wide range of uses. Different admixtures have different functions: for example, admixtures have the function of reducing water, air-entraining agents have the function of adding gas, and coagulants have the function of regulating coagulation. In general, admixtures can give full play to their effects:
Concrete admixtures can improve construction conditions, ease physical labor, play a positive role in ensuring and improving construction quality, and can make previously arduous tasks easier High-quality engineering projects are carried out under current standards. For example: high-efficiency admixtures can be added to configure extremely high-strength concrete under construction site standards, and concrete pumping can be configured. Maintenance time can be reduced, formwork can be removed in advance to speed up template capital turnover, and prestressed reinforced concrete can be stretched and sheared in advance. In other words, the project progress can be accelerated.
Many admixtures can improve the strength of concrete, improve its performance, compactness, cold resistance, impermeability, and improve its drying and shrinkage properties. Some admixtures can improve the resistance of construction steel bars. Corrosive, etc. It can save resources, such as saving concrete; it can improve the adhesion of concrete, thereby promoting the smooth development of the vibrating intensity and plastering process, reducing the vibrating intensity and closing time, and reducing heat and oil consumption.
Reasonable use of various admixtures and at least the following points must be ensured to ensure the quality of project construction.
(1) Expressive intake
In the construction of the project, accurately mixes the outer agent according to the design scheme intake. If it is a liquid, the liquid concentration value should be measured accurately; if it is a granule, it should be added evenly and accurately so that the deviation is controlled within ±2%.
(2) Incorporation evenly
It is necessary to find ways to evenly distribute the admixture in the entire mixture so that it can fully utilize its effect and prevent adverse effects caused by excessive concentration. If the granular agent is added together with concrete, it should be spread out and the dry mixing time should be appropriately increased; the liquid agent should also be spread evenly to avoid local concentration.
(3) The mixing process is accurate
For concrete mixed with several types of admixtures, attention should be paid to the order of their mixing. It may be added first, or it may be added first. It is added later, and some are added after it is shipped to the site. Therefore, there is a certain order in adding admixtures and cannot be messed up.
(4) Timely replacement
Different admixtures have different characteristics, and admixtures suitable for the current season should be replaced in time, because from December to January in winter, the average When the temperature is already below zero, high-efficiency water-reducing admixtures used in autumn are still used. This type of admixture has a certain retarding effect, and the cold-proof effect is not very good. When the temperature is relatively low, the solidification rate is slower, resulting in No coagulation for 24 hours, and the compressive strength progress is slow. Therefore, from autumn to winter construction measures, the type of concrete admixtures should be changed in advance. In winter, cold-proof and early-strength admixtures should be used to fully prepare for winter construction measures.
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