Evaluation of the causal effect of the surface performance-graded (SPG) specification for chip seal binders on performance

Abstract The Texas Department of Transportation (TxDOT) has implemented a Surface Performance-Graded (SPG) specification for chip seal binders as a special provision available for use in their annual statewide chip seal program. The SPG specification was established to improve chip seal field performance by limiting aggregate loss and bleeding during the critical first year after construction. The objective of this study is to evaluate the effect of the SPG specification on chip seal field performance by reviewing selected highway sections (HSs) from previous TxDOT annual statewide chip seal program built from 2011 to 2014. The review of chip seal binder laboratory characterization and field monitoring results is based on: (a) the finalized SPG specification with validated high and low temperature limits, (b) an updated SPG climate-based map with 6 °C increments for practical consideration, and (c) an improved Surface Condition Index calculation method to eliminate subjectivity from field inspection personnel. The review results are used to compare the SPG criteria with field performance. A causal effect analysis is performed to assess the average treatment effect on HSs from implementing SPG specification for chip seal binders. HSs are categorized into treatment and control groups based on SPG results, and 19 well-matched pairs were selected by utilizing a nearest-neighbor matching algorithm to minimize selection bias. Given the random selection of chip seal HSs, an improvement of field performance on HSs that satisfied the SPG specification is validated by a statistical hypothesis test at 95% confidence level.

[1]  Minas Guirguis,et al.  Chip seal aggregate evaluation and successful roads preservation , 2018, Construction and Building Materials.

[2]  Scott Shuler,et al.  Manual for Emulsion-Based Chip Seals for Pavement Preservation , 2011 .

[3]  Lubinda F. Walubita,et al.  Initial Validation of a New Surface Performance-Graded Binder Specification , 2004 .

[4]  D. Rubin.  Causal Inference Using Potential Outcomes , 2005 .

[5]  Gary King,et al.  Matching as Nonparametric Preprocessing for Reducing Model Dependence in Parametric Causal Inference , 2007, Political Analysis.

[6]  Douglas D. Gransberg.  Correlating chip seal performance and construction methods , 2006 .

[7]  J. Dalton,et al.  A unified approach to measuring the effect size between two groups using SAS , 2012 .

[8]  Darren Hazlett,et al.  Performance-Graded Binder Specification for Surface Treatments , 2002 .

[9]  Nasir G. Gharaibeh,et al.  Improving Chip Seal Construction Using Laser Intensity Data , 2020 .

[10]  Mustafa Karaşahin,et al.  Effect of aggregate surface properties on chip seal retention performance , 2013 .

[11]  Andre de Fortier Smit,et al.  Modeling the effect of environmental factors on evaporative water loss in asphalt emulsions for chip seal applications , 2012 .

[12]  T. VanderWeele.  Principles of confounder selection , 2019, European Journal of Epidemiology.

[13]  Mustafa Karaşahin,et al.  Effects of construction-related factors on chip seal performance , 2012 .

[14]  Amy Epps Martin,et al.  Revision and Further Validation of Surface Performance-Graded Specification for Chip Seal Binders , 2013 .

[15]  William D. Lawson,et al.  Chip Seal Maintenance , 2009 .

[16]  Shi Chang,et al.  Evolution of the Surface Performance-Graded Specification for Chip Seal Binders , 2017 .

[17]  Amy Epps Martin,et al.  Revision and further validation of surface-performance graded specification for surface treatment binders. , 2012 .

[18]  D. Rubin.  Estimating causal effects of treatments in randomized and nonrandomized studies. , 1974 .

[19]  Amy Epps Martin,et al.  Surface Performance-Grading System to Grade Chip Seal Emulsion Residues , 2010 .

[20]  Douglas D. Gransberg.  Chip Seal Program Excellence in the United States , 2005 .