Concrete repair and protection technologies
A. REPLACEMENT OF DETERIORATED CONCRETE
Sometimes concrete is so deteriorated that the best solution is to remove the areas that are in poor condition and then reconstruct them. Most of the occasions when it is necessary to proceed in this way, the concrete is carbonated or contaminated.
After having removed the deteriorated concrete through any of the above techniques, the reconstruction should be performed, which can be accomplished by several methods.
If the volume of concrete removed is small, then the most convenient method is to use hand-applied mortar, while if the volume is large, it should be grouted with poured concrete or mortar or projected concrete or mortar.
B. RESTORATION OF LOOSE CONCRETE SECTIONS
This method of repair is closely related to the replacement of deteriorated concrete sections since it often requires the same procedure as when performing the refilling with new concrete after having removed the deteriorated concrete.NThe restoration of concrete sections can be accomplished with mortar or concrete,Napplied in different ways depending on the situation and the extent of the section to be restored:
C. CRACK INJECTION
The purpose of crack injection in concrete is to fill cracks or voids. Depending on the purpose of the injection, the type of structure and the size of the crack or hole to be injected, various injection systems can be used, using a combination of materials and pressures.
Moreover, prior to making the crack injection, it must always be ensured if it is an active or passive crack, meaning in the first case that the crack will move, and in the second one that it is completely stable. Flexible injection will be used if it is an active crack.
Other elements repair
A. REPAIR OR REPLACEMENT OF EXPANSION JOINTS
When a joint is deteriorated or is becoming loose, a repair or replacement must be undertaken since, if the joints are not properly protected, elements can penetrate through the joint and severely damage the structure.
If sealants are used for the repair and replacement of the joints is the option, the remaining part of the original joint must first be removed and subsequently, the sealant will be applied, and the joint will be filled. If just repairing, the sealant should be applied directly to the damaged areas in such a way that the joint becomes continuous again.
If the joint was sealed with a flashing (an element made of a highly deformable material that is placed in the joint to prevent, in the first place, the ingress of water) and this is damaged, a solution can be taken to remove it and place another one or to repair it, e.g. with a leak stopper.
B. REPAIR OR REPLACEMENT OF BEARINGS
When the bearings of a bridge are displaced or deformed, they need to be repositioned, repaired or replaced as soon as possible so that they can continue providing load transfer, since any progression of these pathologies can lead to the collapse of the structure. A project is required to design both bearings, jacks and temporary supports.
The most common process to be followed is as outlined below:
C. REPAIR OR REPLACEMENT OF BARRIERS:
Safety barriers protect users by slowing down the impact and preventing the vehicle from leaving the road and falling over the bridge, as well as preventing pedestrians from tripping.
It is therefore essential that these safety elements remain in optimum condition under all circumstances. If it is a metal structure special attention should be paid to the grounding system.
Two types of actions can be distinguished: minor repainting and restoration works; and replacements, when the barriers are so damaged that it is better to remove them and replace them with new ones.
D. REPAIR OR REPLACEMENTS OF DRAINAGE SYSTEMS AND ELEMENTS:
Water and moisture in a bridge have a direct influence on its structural behaviour and can lead to loss of support and have a detrimental effect on the durability of its elements. The evacuation of water is therefore vital for the correct functioning of the bridge.
These elements must be in optimum operating condition, eliminating any obstructions they may have. In the event that there are areas in poor condition, small maintenance actions can be carried out, and in cases of major deterioration, these elements can be replaced.
