Productivity in road pavement maintenance & rehabilitation projects : perspectives of New Zealand roading contractors on the constraints and improvement measures : a thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy (PhD) in Construction, School of Built Environment, Massey University, Albany, New Zealand

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Massey University
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Road Maintenance and Rehabilitation contractors (RMRCs) – and indeed all contractors handling public sector projects – face the challenge of performance-based rewards, which seek to maximise tax dollars by ensuring whole-of-life best value in the project delivery process. To be successful, a contractor’s productivity and performance should remain high and resilient to internal and external constraints in the project environment. There is a lack of research on a practical approach to modelling and prioritising performance constraints in the roading sector. This study aimed to investigate the priority constraints RMRCs face in New Zealand (NZ) as well as strategies for improvement. The thesis presents the final findings of interview-based qualitative surveys of medium- to large-sized roading contractors in NZ, followed by a questionnaire survey (quantitative) to prioritise the constraints found during the first stage of the research. Empirical data then were analysed using descriptive statistics and SPSS-based principal component analysis. The results showed - in diminishing order of influence - the following four principal items extracted from the initial 68 constraints identified from the interviews: process, operating environment; input; and output constraint groups. The most influential constraints in the four groups are inclement weather, frequency of design changes, inadequate supply or high cost of required resources, and post-construction defective or non-compliant work. The findings contribute to the relevant body of knowledge by revealing critical factors constraining the productivity performance of NZ RMRCs and associated improvement measures. The Input-Process-Environment-Output (IPEO) constraint model is seen as being more practical and easy to follow by industry stakeholders than the internal-external risk approach reported in the literature; it presents new and more enriching perspectives into how contractors could leverage their limited resources to address key constraints.
Pavements, Roads, New Zealand, Maintenance and repair, Contractors, efficiency, performance, productivity, road maintenance & rehabilitation