The pH value of underground water

The pH of the mountain water plays an important role. When the the pH value of the mountain water increase, lime is excreted from the water. The theory say, that over a pH value of 10, no more lime can be disolved in the mountain water. This mechanism is often a problem when we mix 2 water together which have different pH values. In such cases, we can observe the the formation of strong deposits (near to the mixing point).Responsible for the pH increase of the mountain water are, the alkalis of the shotcrete and its additives.

At the beginning of the construction work, the pH value increase is very strong and causes the largest deposits, followed by a slow reduction as a result of leaching through the mountain water. Depending on the quantity and quality of the binders, the influence extend over 10 years. Therefore Alkali-free concrete admixtures are available on the market. However, the effort should be compared with the yield.