Maintenance of external paving
Correctly designed and constructed external concrete pavements should have a long service life and require only limited maintenance. However some changes in the condition of the pavement over time and some maintenance, especially at joints, are to be expected. Therefore, it is strongly recommended that routine monitoring be undertaken at intervals to assess the condition of the pavement and to also assess the rate of change.
Some loss of texture or surface mortar is to be expected over time, particularly in heavily trafficked areas, and should not be regarded as unusual. It is relatively common in very heavily trafficked areas of industrial concrete paving to find after several years that the upper surface mortar layer has been lost, giving an exposed aggregate type finish. If brush-finished concrete paving is heavily trafficked by vehicles with small hard wheels rapid abrasion of the surface is to be expected. Damage can also occur at locations where jockey wheels of trailers are dropped onto the surface. If the surface texture becomes inadequate for skid resistance purposes, the surface can be retextured by mechanical methods, e.g. by using a concrete plane or enclosed shot blasting machine. Any re-texturing will clearly affect surface appearance.
Freeze-thaw damage often becomes apparent as small localised patches of shallow spalling or ‘shelling-off’ of the upper mortar layer. Eventually, damage may lead to the partial or complete loss of the surface mortar layer and in the worst cases deep pitting of the surface.
Joints require the most maintenance and thus regular monitoring of their condition is very important. Sealants must be replaced as necessary; unfilled/unsealed joints can lead to surface water percolating down into the sub-base and subgrade, leading to a possible deterioration in the support to the paving. In addition unfilled joints filled with detritus give an increased risk of joint edge damage.
Most cracking that occurs in concrete paving is due to restrained contraction and will not normally affect the performance of the paving. Sometimes the edges of wider cracks may break down under the action of traffic. If significant vertical movement or differential vertical displacement is apparent at joints or cracks further investigations should be undertaken. Excessive vertical movements at joints or cracks may lead to localised structural failures around the joint or cracks.