What should we pay attention to when inspecting the quality of concrete admixtures?

1. Admixture product quality inspection, measuring the composition, performance and quality stability of a certain admixture to determine whether it meets the specified physical and chemical performance indicators. Such as appearance, active substance content, solubility, specific gravity, pH value of aqueous solution, chloride ion content, sulfate content, sugar content, foaming property, surface tension, and whether there is corrosion of steel bars, etc.

2. Performance inspection of admixtures mixed into cement slurry (also known as clean slurry) to check the performance indicators that admixtures should meet when adapting to different types of cement. Its measurement items include slurry fluidity, setting time, exothermic changes in hydration heat, stability, settlement test, etc.

3. The admixture is mixed into the concrete for adaptability test, that is, the concrete mixed with the admixture is compared with the benchmark concrete to test the water reduction rate, bleeding rate, and content of the new concrete. Air volume, condensation time, slump loss, and test the compressive strength, impermeability, frost resistance, shrinkage, creep, and corrosion of steel bars after hardening of the concrete. The quality control indicators (including benchmark concrete) that these test projects should achieve and the quality requirements for test materials are clearly stipulated in the “Technical Specifications for the Application of Concrete Admixtures”. The purpose of this part of the inspection is to determine whether the selected admixtures are suitable for the concrete properties formulated with all other materials, including cement varieties, and whether they can meet the design requirements for concrete properties. After passing the above-mentioned test, the construction department can adjust the mix ratio based on the actual selection of sand, stone and other mixing materials for construction, combined with the above-mentioned test results, and conduct optimal testing of the admixture dosage range, and provide the results during construction. use. </p