Tire-Pavement Noise as a Construction Quality Indicator
Community & Cultural Concerns, Environmental Process
Research Idea Scope
RESEARCH PROBLEM STATEMENT
Paying a contractor based on the quality of pavement construction is not new. In fact, nearly all specifications accomplish this, be it through means & methods, end-result, or performance standards. In recent years, the latter of these has been emphasized for a number of reasons, with the most obvious being the simplicity and relevance from the perspective of the owner-agency and the traveling public.
Functional performance of a pavement can be defined by the manner in which it serves both the road users and society. Indicators of functional performance that are widely tested include smoothness and friction, with the former commonly used as a means to assure quality construction, and thus reimburse the contractor accordingly. Friction, while measured, is instead used as a means to program rehabilitation activities rather than as an indicator of construction quality.
A third important functional performance indicator is tire-pavement noise. Until recently, the methods to measure tire-pavement noise in a relevant and accurate manner did not exist. This is no longer the case with on-board sound intensity (OBSI) both standardized and regularly used by practitioners. Furthermore, with surface texture being the most important physical characteristic of the pavement that affects noise, this too can be measured as a surrogate parameter.
With the technology now readily available for both tire-pavement noise and pavement texture measurements, it is only logical to investigate the feasibility of using noise as an indicator of construction quality for possible adoption in quality control, assurance, and/or acceptance. Specifics of this process could be modeled after similar initiatives already being used by highway agencies in other countries.
The following are objectives of the proposed research:
1. Investigate the feasibility of measuring tire-pavement noise (or a surrogate measurement such as texture) as a quality parameter for pavement construction.
2. Recommend test protocols and any potential revisions that might be necessary for use in assessing construction quality.
3. Develop model language for both a quality management plan and a performance standard that accommodates tire-pavement noise.
4. Develop guidance for owner/agencies to derive pay adjustments based on tire-pavement noise as a construction quality indicator.
These objectives can be met via the following tasks divided into two phases:
1. Search the literature and other sources of information – particularly foreign sources – on the use of tire-pavement noise as a construction quality parameter.
2. Synthesize all available information, including specific specifications and test protocols that are currently in use for this purpose.
3. Develop model language that can serve as relevant sections of both a quality management plan and a performance specification, including guidance on deriving pay adjustments.
4. Identify candidate projects for “shadow” field trials of the recommended model specifications.
5. Document and deliver an interim report to include specific plans on how to evaluate the recommended model specifications, and how adjustments will be made based on the results.
6. Execute the approved field trials. Test the pavements as recommended in the model specification, and report what adjustments to the operations and/or pay factors would occur if the project had included the specification as recommended.
7. Refine the specifications as needed to accommodate the lessons learned from the field trials.
8. Document and submit final guidance, and a final report on the project.
Urgency and Payoff
There is an ever-increasing awareness of highway noise as a quality of life issue. Noise is often one of the top concerns in any road improvement project and the public is recognizing the benefits of and thus demanding quieter pavements. Tire-pavement noise is often the most significant contribution to highway noise, and thus its control (through control of the pavement surface) during construction is logical. Pavement is also the only noise generating component that DOTs have direct and immediate control over. The range between the quietest and loudest pavements can be dramatic, and lowering the noise at the vehicle source by avoiding louder pavements could be a relatively easy and low-cost form of noise mitigation. Controlling the noise-generating characteristics inherent with the pavement surface during construction can follow the same rationale as controlling pavement smoothness during construction.
Furthermore, pavement rehabilitation projects have an increased probability of being funded if an additional environmental benefit included lower community noise levels – potholes are filled and the traffic noise is reduced. Noise complaints could be avoided or lowered if a quieter pavement strategy was designed and constructed adjacent to sensitive noise receptors. DOTs would be viewed as positively addressing the environmental impacts of noisy transportation infrastructure.
Quick implementation might first be attempted as a quieter pavement policy document – identification and avoidance of loud pavements near sensitive receivers through placement of quieter pavement strategies. Performance specifications might be incentivized to provide a quieter pavement near sensitive receivers.
The results from this study will include model language for use in a quality management plan and/or performance specification. Existing test protocols such as AASHTO TP 76 (on-board sound intensity) can likely be used for this purpose.
Adam Alexander, ADC40 Transportation Related Noise and Vibration Committee