The previous two issues talked about the causes of oil spills, waves, gnawing edges, bulges, cracks and subsidence on asphalt pavement and how to deal with them. Finally, let’s analyze the problems of loose pavement and potholes among the common diseases of asphalt pavement.
Loose
Loose asphalt pavement is mainly caused by the small asphalt oil-stone ratio during paving, resulting in low bonding force between asphalt and aggregate. Or the temperature during construction is low, and the internal gaps of the mixture are too large during paving, which will cause the road surface to become loose due to repeated vehicle loads later. Or when the mixture is mixed, the pellets are coated with dust, which causes the adhesion between the pellets and asphalt to deteriorate, resulting in loosening of the mixture. Or there are other reasons, which I won’t go into details here.
There are two main traditional methods for treating loose pavement diseases. One is to spread new asphalt oil and coarse aggregates such as stone chips on the original pavement and then repeatedly roll it. This method can make full use of the original pavement materials, but since it cannot guarantee the quality of the repaired pavement and cannot fundamentally solve the problem, it has been basically eliminated.
The second method is to cut off the pockmarked pavement and re-pave it with the same asphalt mixture as the original pavement. This maintenance method can ensure the quality of the project, and can also excavate and repair unqualified base layers. However, this method requires the entire original road surface to be excavated, and the removed original road surface materials can only be discarded, which is a waste of resources. On the other hand, the replaced road surface affects the driving comfort.
With the advancement of technology, asphalt pavement thermal recycling technology has begun to be widely used in pavement maintenance. This technology can combine the advantages of the above two processing methods, which can not only make full use of the original pavement materials, but also fully ensure the construction quality of the repaired road.
Potholes
According to their manifestations, potholes can be mainly divided into potholes on the upper surface layer of the road, potholes on the mid-surface layer and potholes on the subgrade. Different pits have different mechanisms. The pits on the upper surface are mainly caused by improper handling of the asphalt mixture during paving, insufficient bonding between aggregates, excessive gaps, shallow and smaller pits caused by rain and traffic loads, etc., and their depth is generally less than 5CM.
The occurrence of potholes in the mid-surface layer is mainly due to the fact that a certain pavement gap in the road surface is too large, rainwater pours into and stays in it, and the deeper potholes are formed by the driving load, and their depth is generally less than 10CM;
The pits caused by the roadbed are due to the fact that the roadbed was not treated in time during paving, and groundwater intruded later and damaged it. The mud turning is more serious and the pits produced are deeper, generally more than 10CM in depth.
For potholes on the upper surface or potholes in the mid-surface layer, an insulation truck or asphalt repair truck can be used to directly repair the road surface. For potholes caused by damage to the base layer, the damaged part of the road surface and roadbed must first be eradicated, and then measures must be taken to reinforce the foundation, and then the road surface layer can be laid.