Key Components in Long Term Sustainability of Concrete Pavement Systems & Sustainability Considerations for PCC Pavement Design and Construction

This paper addresses key issues regarding important factors affecting the sustainability and long-term performance of PCC pavement structures. Key distress types and their associated features are discussed in terms of their effect on performance and sustainabilityin terms of specific pavement components. Relevantmaterialproperties are also identified and discussed as to how they are represented in laboratory and field testing. A process to manage inspection resources is described and illustrated.

Pavement sustainability can and frequently does have a broad range ofdefinitions that mayreflect conflictingobjectivesand purposesbut in the context of this paper, pertainsexclusively to the quality of the structural-relatedperformance of a pavement structure over givenservice life. Furthermore, the definition of sustainability referred to in this documentwill betied to perpetual pavement longevity asfounded inthe life cycle assessment (LCA) and itscapability to be sustained in its original configuration over a given period of time(1). Inherent to such adiscussionistheoptimization of an acceptable level ofpavementstructural conditionover timeand theminimization of the impact of current rehabilitation decisions to limit the capability of future generation to achieve cost-effective repair alternatives. Achieving sustainablepavementperformancefirst of allinvolvesgainingan understanding of pavement behavior and how that behavior isaffected by key pavement subsystems and their associationwith cycles of deterioration, which if allowed to become advanced enough, will affect thefunctionaland structural capacity of a pavement and limit its overall use.It also involves the understanding of the performance-related functionality or the utility of common material tests used for inspection and specification purposes to represent performanceand to serve as an aid in the assessment of selected design, material, construction, or maintenance combinationsto provide sustainable performance. Discussion in this documentwill address how the assurance of a a sustainable levelof performance can often be governed bythe success oftwokeyactivities:Performance monitoring, andConstruction inspectionThis is a key issue with regard to sustainability and to make the outcome of these two components beneficial over a long period of time, it is important that key activities for each component be identified and elaborated in order to better insure the result of the application and optimal benefit of each. The first of these activitieswill be elaborated later but it does involve a very important focus pertaining to the maintenance of a pavement structure at a high level of service and minimizing the cost to do so over a given period to time. The second activityhas traditionally been high onthe list of theresponsibilities commonly undertaken by the projectownerduring constructionto positively affectthe outcome of the overallconstruction effort,as it should be.One of the key aspects anyinspection program is to ensure quality in the constructed product and to prevent, to the extent possible, the development of unexpected, premature distress in theconstructedpavement and infrastructure. Premature distress is oftena function of and dependent uponprevailing weather conditions which oftenaffectsthe quality builtinto the constructed product. Onepurpose of inspection is to minimize the effects of circumstancesinvolving methodsof construction, materials, and weatherthat can lead to premature failure; the minimizationis facilitated by testsand checksconducted by the inspector to provide an indication of less than acceptable conditions when they exist. Most tests selected for use in construction inspectionand specificationyield useful values of measured properties or parameters that reflect the quality of the constructed product and in some casesthe level of expected service over the designlife. Thebetter a testmethodis able to detect a key propertyor a characteristicthe better is its utilityto indicate performance. Not all tests address or involve the same amount ofvariability orriskin determining unacceptable resultsand as a consequence,do not or would not share the same level of testing liability due to perhaps a  higher confidence level in measuring a meaningful test parameterand/or achieving an acceptable level of testing precision.