Water containing abrassive matter in suspension

• High-quality concrete is very resistant to damage by abrasion from fast flowing water containing grit or other abrasive material .
• The degree of damage caused will depend on a number of factors of which the following are the most important :

a. The quality of the concrete in terms of compressive strength , cement content , the wear resistance of the fine & coarse aggregate .

• The degree of damage caused will depend on a number of factors of which the following are the most important :

b. The smooothness of the surface of the concrete
c. The velocity of the flowing water
d. The quantity of the grit carried , its particle shape * its abrasive characteristic are not always obvious for example china clay waste can be extremely abrasive .
e. The flow characteristics such as whether continuous or intermittent and the variation in the quantity of grit being transported .

Impact from a high-velocity water jet .

• The effect of a jet of water of very high velocity striking a concrete surface is to erode the cement paste , resulting in the loosening of the course & fine aggregate .
• The amount of damage done depends on the velocity of the water at the point of impact & the quality of the concrete int erms of compressive strength & cement content .