How to return cement base caulk alkalinity? The effect of adding calcium formate is unusual？

People who do construction projects know that return is a common problem in silicate products. In recent years, in order to reduce the occurrence of this common problem, the construction industry has used ceramic tile caulk to apply it to cement. As a mortar early strength agent, calcium formate is widely used because of its unique properties, which can accelerate the hardening rate of cement-based joint fillers and improve the early strength of cement-based joint fillers.

The caulking material is divided into dark external wall caulking material and internal wall caulking material, and the caustic return often occurs in the winter fog-day construction or the external wall after less than 24 hours after construction, local whitening and white crystal material precipitation, which seriously affects the decorative effect of the caulking product.

Commonly used caulking materials are: white cement, putty powder, caulking agent, sealant and so on. Among these materials, white cement and putty powder are traditional caulking materials, but both of these materials are lacking in performance. The application of calcium formate is superior to traditional caulking materials.

Properties and selection of calcium formate

Calcium formate is a white powder product with the molecular formula C2H2Ca04, which can speed up the hydration rate of cement, thereby improving the early strength of cement-based caulk, so adding an appropriate amount of calcium formate to the winter formulation of cement-based caulk should speed up the formation of CSH gel, thereby reducing the occurrence of return alkali.

The production of alkali scale will not only be affected by the construction environment, ceramic tile as the base is often the root cause of the problem. The selection of appropriate calcium formate products and dosage is very important to improve the anti-alkali property of cement-based joint material. In the winter formulation system of cement-based joint filler, 1-2% calcium formate content can significantly reduce the return alkali of cement-based joint filler.