Projects

Background

Intelligent compaction (IC) is an alternative to replace the traditional approach to yield better compaction control. IC was initially developed in Europe for the compaction of granular materials in 1980’s. The core IC technology is the accelerometer-based measurement system to monitor the stiffness of the compacted materials. The density or compaction level of the materials can be obtained by correlating the density with stiffness. In addition, a high precision global positioning system (GPS) and infrared temperature sensors (in the case of asphalt) are usually fitted to the compactor to map the precise position and the surface temperature [2]. As a result, IC can monitor in real time the compaction condition of the entire section. Generally, the benefits of IC for asphalt pavement include:

Improved uniformity of density/modulus, which can be expected to lead to better performance of the unbound pavement;
Improved efficiency of the compaction process, which may result in cost savings;
Continuous record of a stiffness, which can identify those weak points in pavement or substrate layers;
Improved documentation of the compaction process and therefore improved process control records;
Possible linkage with building information modelling (BIM) for pavement in the future with full record of data.

However, the implementation of intelligent compaction requires considerable investment and therefore the benefits need to be quantified both in technical and economic terms. In addition, some limitations were also found with IC, such as the weak correlation between IC measured value (ICMV) and the core densities (Chang et al., 2017). Hence, there is a need to validate the proposition that intelligent compaction leads to better quality and consistency of layer and to investigate how much this will extend the life of the unbound pavement. There is also a need to investigate whether IC results may be used to reduce the number of spot measurements that have to be carried out to confirm density compliance.

Project Objectives

1. Develop a data standard for unbound/subgrade compaction using IC

2. Quantify the benefits of using IC for unbound materials from technical and economic aspects through cost-benefit analysis (CBA)

3. Validate the data standard and CBA analysis through field trials undertaken with partners

4. Identify other parameters that need to be measured to make rollers more intelligent

5. Recommend methodology to incorporate of IC into bidding of road construction projects