Preventive Road Maintenance: The Three Phases of Deterioration

Roads are crucial infrastructure that connect people, goods, and services across different regions. However, with time, usage, and exposure to environmental factors, they start to deteriorate. Understanding the three phases of road deterioration can help transportation agencies and road managers plan and implement effective maintenance strategies to prolong road lifespan and prevent costly repairs.

The three phases of road deterioration include:

1) Initial densification

2) Gradual deterioration

3) Rapid deterioration

Austroad’s model below takes into account factors such as initial densification, which occurs within the first 12 months after construction due to traffic loading, which can lead to certain forms of permanent distress such as rutting and roughness. However, it's worth noting that the model may not account for the potential increase in pavement strength that can result from initial densification.

The second phase of road deterioration is known as gradual deterioration, and it is the phase in which most in-service pavements operate. During this phase, deterioration proceeds at a low, virtually linear rate. Modelling at this phase is typically used to forecast the future condition of a pavement and determine necessary maintenance.

The third and final phase of road deterioration is referred to as the rapid deterioration phase. This phase is characterised by a deterioration rate that is two to three times higher than the rate of gradual deterioration. Predicting this phase is difficult, as the pavement approaches ultimate failure. Some recent RD models, such as those developed by Austroads in 2014 and 2015, have been designed to predict rapid deterioration. However, these models are based on limited data and are not yet considered fully reliable predictors of rapid deterioration because of the limited observational data available.

Figure 1: The Three Phases of Road Deterioration (RD) from Austroads 2023.

We believe that preventive road maintenance is the best strategy for road managers to manage road deterioration. By identifying the three phases of road deterioration and implementing appropriate maintenance measures, road managers can extend the life of roads, save money on costly repairs, and prevent accidents and vehicle damages caused by road defects. Therefore, it is crucial for road managers to prioritise preventive maintenance as an essential part of their long-term road management strategy. By doing so, they can ensure that roads remain a reliable and safe means of transportation for generations to come.

Reference

Austroads 2023, ‘Austroads Road Deterioration Model Update: Cracking,’ Austroads Technical Report, Publication No. AP-T368-23.