mechanical causesReading time:
There are three categories of mechanical causes :
- excessively high permeability: in fact, achieving a very high level of compactness with amounts of cement varying from 300 to 400 kg · m–3 constitutes a minimum condition when faced with aggressive water;
- the existence of crevices and/or cracks caused by unsatisfactory poor conditions, (e.g. concrete joints) and that can be improved by increasing concrete plasticity by using a water/cement proportion of less than 0.45 or by using a plasticiser;
- erosion caused by water circulation velocities in pipes in excess of 4 m · s–1 or by excessively high heat gradients.