The natural stone offers very remarkable conditions of conservation, durability and resistance, being the recommended material for the elaboration of pavements subject to high demands of use and climatology.
The causes of damage produced to stones must be rectified to resolve the pathological process that affects the stone, since repairing the damage does not imply the elimination of the origin because the signs of the pathological process will continue to manifest themselves.
The causes of the damage can be direct – the action immediately produces damage – or indirect, due to mistakes made in the process of design and/or elaboration of the pavement.
Direct causes are classified according to the type of damage caused. In this way, we can consider direct physical, mechanical and chemical causes. We will focus this time on mechanical damage, which is the cause of damages such as cracks, fissures, detachments and erosion and include all the strongest actions that the stone element can withstand.
The actions are:
- Overloads of use: they are superior mechanical actions that were foreseen in the calculation, such as loads and overloads that produce cracks, fissures or deformations in the element.
- Impacts: derived from the fall of hard bodies.
- Abrasion or wear: originated by the circulation of pedestrian or vehicular traffic.
- Breakages: In this type of pathology, the position of the breakage must be distinguished, being able to be located in the mortar-stone element junction (due to the lack of adherence between them) or in the element itself.
- Detachments: can be produced by expansion or compression of the support structure.
In the detachment by dilatation it is recommended to act especifically on the row of adjacent elements to the joint, so that it is executed as planned in the project.
The compression damage causes a differential seat in the stone tiles, which causes detachments by compression on the support structure. Depending on the magnitude of failure, different actions are carried out: on the entire pavement or at a single point.
- Erosion or wear: to repair the damages caused by wear, a surface finish identical to the original one can be re-done or the damaged stone element can be replaced when the quantity of lost material is considerable.
Eva Portas Fernández
AREA OF TECHNICAL CONSULTANCY
TECHNOLOGICAL FOUNDATION CENTRE FOR GRANITE OF GALICIA