MarbleThe rate of water absorption in the rock
The amount of water absorption in the rock is the amount of water that the rock absorbs in terms of its dry weight percentage. The amount of water absorption in rocks is very different, but in general, water absorption in igneous rocks such as granites is very low. But limestone and sandstone have a high water absorption rate.
Relationship between porosity and water absorption
Porosity indicates the volume of voids in the rock, so a rock with low porosity absorbs a small percentage of water, and a rock with high porosity absorbs and retains large amounts of water.
The retention of water in the rock also depends on the size and shape of the pores. If the pores are small, they will absorb more water due to their capillary nature. If the pores are large, water can be removed more easily, so sometimes we may have a low percentage of water absorption despite the high porosity.
The effect of high water absorption on rocks
The effect of high water absorption on rocks
High water absorption in rocks causes them to rot and wear and reduces the life of rocks. These types of rocks are mainly so-called hollow due to high porosity and have low compressive strength and are crushed sooner. Water remains inside these pores and freezes in cold weather and winters, and because the volume of ice is more than its liquid, it expands internally and eventually leads to cracks in the rock.
Percentage of water absorption in building stones
In general, the stones used in the building must have low water absorption and according to ASTM97 standard, the maximum water absorption in them must be 0.2 to be acceptable.
How to reduce the percentage of water absorption
The percentage of water absorption in rocks can be reduced by using nanotechnology or so-called water proof or rock waterproofing. If the coating is based on thinner, it has a higher price, but in addition to waterproofing the stone surface, it can also be polished and makes the stone surface shiny and beautiful.
These coatings will not have a permanent effect and must be re-coated after a maximum of 4 to 5 years.