The water reducing agent produces a good water reducing effect in the concrete works and has a direct impact on the concrete performance.The surface of the water reducing agent has a good active substance. Under the chemical action of the active material, the cement particles in the concrete are adsorbed by the water reducing agent, and the cement particles generate the same kind of electric charge.The cement particles are separated under the action of the water reducing agent active material, reducing the surface tension of the cement and water, and increasing the contact area.The water content of the cement particles is fully reacted, and the effect of reducing the amount of cement or water is finally achieved under the condition of maintaining the strength.
Fully understanding the characteristics of high-efficiency water reducer and applying it correctly will not only help improve the construction quality, but also improve economic benefits and make it better for engineering construction services.
1、Ordinary water reducer and superplasticizer should be tested for pH value, density (or fineness) and water reduction rate before application, and can be used only after meeting the requirements.The determination of the optimum dosage must meet the performance requirements such as design strength, workability, durability and economy of the engineering environmental conditions.According to the recommended dosage provided by the supplier, a reasonable dosage is obtained through trial matching.Excessive amount of high-efficiency water reducing agent causes serious fouling of cement concrete and large loss of cement slurry, resulting in insufficient compactness and affecting strength.
2、The water reducing agent should be formulated into a uniform solution.The harmful effects of admixture precipitation are the same as those of admixtures.Solid precipitates that are not dissolved in the solution should be removed daily.According to the needs of the project, ordinary water reducing agent and superplasticizer can be combined with other miscible admixtures.
3、Adding a retarder, a high temperature retarder, a plasticizer or a retarding type water reducing agent suitable for cement in the high-efficiency water reducing agent can reduce the loss of hot weather slump,When transporting cement concrete with a mixer or tanker, a superplasticizer can be added twice at the pouring site.After rapid mixing and even discharge, no more water is added, and the pouring, vibrating, facing, etc. are completed quickly; the retarding type high-efficiency water reducing agent is used.
4、The health link is the key link to ensure that the cement concrete structure does not produce cracks and micro cracks.Therefore, the highway engineering cement concrete structure with ordinary water reducing agent and high-efficiency water reducing agent should be strengthened and insured as soon as possible.Cement concrete members with ordinary water reducing agent are not suitable for steaming;The cement concrete component with the retarding type water reducing agent must ensure that the cement concrete forms a certain structural strength after a certain period of static stop to be steamed.Cement concrete mixed with superplasticizer can be cured by steaming.