Texas A&M University


Ongoing/Completed Research Projects

     Title:  Composition of Local Studies and Regional Calibration of Pavement ME Design for Rigid and Flexible Pavements in Oklahoma

     Sponsored by Oklahoma Department of Transportation (ODOT), PI: M. Sakhaeifar (pending).


     Title:  Comparative Analysis of Tack Coat, Underseal Membrane, and Underseal Technologies - ongoing project

      Sponsored by Texas Department of Transportation (TxDOT), co-PI: M. Sakhaeifar.

      Abstract:  Several options are available for preparing a surface prior to an asphalt overlay. These include traditional tack coats, non-tracking tack coats, thicker spray-applied underseal membranes, and traditional underseals. Tack coats, with a shot rate between 0.04 and 0.14 gallon (gal)/square yard (sy), are expected to provide better bonding. Underseal membranes (0.13 – 0.3 gal/sy) and underseals (>0.3 gal/sy with rock) are expected to reduce moisture infiltration and reflective cracking. However, these benefits have not been sufficiently quantified, and neither has the overall impact on the asphalt overlay service life. Some of these approaches can have considerably higher costs of materials and equipment. Currently, it is unknown whether the added benefits of these technologies (potentially longer service life) result in cost savings to the Receiving Agency.
The objective of this study is to evaluate the performance of asphalt overlays achieved with different tacking and sealing technologies, namely:
  •   Traditional tack coats,
  •   Non-tracking tack coats,
  •   Underseal membranes from a spray-paver, and
  •   Traditional underseals.
In the work plan, the research team shall evaluate each technology with respect to:
  1)   Layer bonding,
  2)   Sealing against moisture,
  3)   Resistance to reflection cracking, and
  4)   General overlay condition.


     Title:  Investigation of Improvement of Sulfur Extended Asphalt (SEA) - ongoing project

     Sponsored by Saudi Aramco from Saudi Arabia, Collaborative Research Project among King Faisal University (KFU), University of Texas at Austin (UT Austin), University of Illinois Urbana Champaign (UIUC) and Texas A&M University (TAMU), PI from TAMU: M. Sakhaeifar. 

      Abstract:  The objective of this research project is to comprehensively evaluate the long-term performance of sulfur extended asphalt (SEA) binders and mixtures with the intent of using this information to (1) identify optimal concentrations of sulfur for specific types of mixtures, (2) identify any modified forms of sulfur that can improve the up scaling and implementation of this technology, and (3) develop methods to design and evaluate sulfur extended asphalt mixtures and pavement test sections for implementation and routine use including the use of the more recent methods such as the Superpave mix design method and assessment of efficacy for specific applications by traditionally popular tests.


     Title:  Review of Oregon Department of Transportation Asphalt Mix Specification Phase II - ongoing project

     Sponsored by Oregon Department of Transportation (ODOT), co-Investigator: M. Sakhaeifar.

     Abstract:  Specifications of construction materials and methods are significant in the success of roadway paving projects. Many test methods and new technologies are used in both quality control and quality assurance. Hot mix asphalt (HMA) is unique in that it consists of aggregates and asphalt binders, and other additives to meet the desired specification. The complexity of HMA requires tests, statistical analysis, and verification to reach the desired goal and balance the various elements. Each Department of Transportation (DOT) has a standard specification, typically established jointly by contractors and the DOT. These standards differ from state to state. The differences come from many factors such as climate condition, traffic loads, past experience, and the availability and varying quality of materials. There are few overarching goals in this study to develop techniques and practices to use test data to gain a better understanding of the mix properties and behavior. 

     Title:  Compaction of Soils and Base Materials using Superpave Gyratory Compactors - ongoing project

     Sponsored by Texas Department of Transportation (TxDOT), co-Investigator: M. Sakhaeifar.

      Abstract:  The Receiving Agency employs impact hammer compaction in test procedures Tex-113-E and Tex-114-E to develop moisture-density relationships and fabricate specimens for strength testing. Although recent modifications to the test procedure enabled improvements in the precision of specimen molded moisture content and dry density, the precision of compressive strength remains a problem. This poor precision of compressive strength can result in conflicting test results regarding whether a material meets specification requirements, resulting in project delays and potentially large implications on the dollar value of a material source. This project will use the Superpave Gyratory Compactor (SGC) to analyze whether SGC compaction improves precision of compressive strength tests for unbound materials; this project also will examine use of the SGC in generation of moisture-density curves. Successful use of the SGC for soils and base materials will better represent field compaction in the lab, achieve more uniform compaction of test specimens, and most importantly reduce the variability of strength results.


     Title:  Experimental Design for Field Validation of Laboratory Tests to Assess Cracking Resistance of Asphalt Mixtures - Link

     Sponsored by Transportation Research Board of the National Academies, National Cooperative Highway Research Program, NCHRP 09-57, co-Investigator: M. Sakhaeifar.

     Abstract:  Cracking is a primary mode of distress that frequently drives the need for rehabilitation of asphalt pavements. There are four major modes of asphalt pavement cracking— thermal, reflection, fatigue, and top-down—that are affected by numerous factors and interactions. In the past, volumetric mixture design gave a reasonable level of comfort for performance since the materials were relatively consistent within a given jurisdiction. Meanwhile, asphalt mix designs are becoming more and more complex with the increasing uses of recycled materials, recycling agents, binder additives/modifiers (such as recycled engine oil bottom), and multiple warm-mix asphalt technologies. These changes have altered the performance of mixtures both positively and negatively so that volumetric mix design alone is not sufficient for evaluating the potential behavior of asphalt mixtures. Thus, there is an urgent need to establish and implement reliable performance tests that can be used to eliminate brittle mixes or used to model asphalt pavements to predict cracking. The overall objective of this research is to develop an experimental design for field validation of laboratory tests selected under this study in order to assess the cracking potential of asphalt mixtures.

     Research Results Digest 399 - Link 

     Cracking Tests Workshop - Link 


     Title:  Selection of Long-Lasting Rehabilitation Treatment Using Life-Cycle Cost Analysis and Present Serviceability Rating

     Sponsored by Oklahoma Department of Transportation (ODOT), November 2013- September 2015, PI: M. Sakhaeifar.

      Abstract:  A wide range of variables influence the selection strategy for rehabilitation and maintenance of pavements. The focus of this study is to conduct a project-level evaluation of high traffic volume asphalt-surfaced pavements located in the state of Oklahoma and develop a performance based rehabilitation strategy. In order to develop feasible rehabilitation strategies, a systematic collection of relevant pavement-related data was provided by ODOT. The collected data includes performance measurements, traffic, climate and structural integrity of existing pavements obtained by falling weight deflectometer (FWD) analysis. These various data sets are supplemented with laboratory testing to determine the material characterization and damage characterization of different surface rehabilitation mixtures. The national highways located in the state of Oklahoma are divided in several pavement family groups. The representative pavement sections for family groups are identified and the required data for analysis are either extracted from existing sources or measured in the laboratory. Three levels of rehabilitation activities including light, medium and heavy rehabilitation are considered for each of the pavement family groups and a mechanistic-empirical methodology is employed to obtain an estimate of the performance of potential rehabilitation activities and their extended service life. A combination of local material properties, structural integrity and environmental condition are used for structural analysis and development of an evaluation output matrix. At the end of this study a series of time-based renewal solutions are recommended for pavement family groups with a similar existing condition and the most cost effective methodology is determined by performing life cycle cost analysis using RealCost software.


     Title:  Performance Evaluation, Specification, and Implementation of Trackless Tack - Link

     Sponsored by Texas Department of Transportation (TxDOT), Fall 2013-present, co-Investigator: M. Sakhaeifar.

     Abstract:  Trackless tack is a popular material for bonding pavement layers. While conventional tack tends to be sticky and messy, trackless tack hardens quickly at ambient temperatures and then reactivates when hot-mix asphalt (HMA) is laid over the tack and compacted. Several trackless tack products have come to market in Texas; however, there are currently no specifications to ensure the products have trackless properties and adequate bond strength.
This project:
   Evaluated the tracking resistance of different trackless tack products.
   Evaluated the bond strength of different trackless tack products and other construction parameters (surface type, tack reactivation temperature, and compaction effort).
   Constructed trackless tack test sections in the field and evaluated initial performance.
   Developed specifications for trackless tack and associated test procedures.

     Project Summary - Link 


     Title:  Pavement Maintenance Guideline for General Aviation Airport Management - Link

      Sponsored by Transportation Research Board of the National Academies, Airport Cooperative Research Program, ACRP 09-11, co-Investigator: M. Sakhaeifar.

     Abstract:  This report provides guidance to general aviation airport managers in determining the most cost-efficient and appropriate preventative maintenance solution to common pavement issues. Research was conducted on the different types of pavement distresses that occur at airports and the types of preventative pavement practices typically used. The guidance includes the effect the climate has on pavement maintenance options and illustrates the range of costs that are expected for each type of preventative maintenance option. In addition to the guidebook, two additional products were developed. The Airport Pavement Maintenance Recommendation Tool (available at is an interactive tool that will assist the user in identifying pavement issues and will make appropriate recommendations. The Field Guide for the Airport Pavement Maintenance Recommendation Tool is intended to assist in identifying the specific pavement issues while in the field.

     Airport Pavement Maintenance Recommendation Tool - Link


Research Projects from Previous Institutes

     Title:  Tire-Pavement Interaction Noise and Surface Characteristics in 2009 Pavement Test Track Cycle

     pooled fund study sponsored by numerous State DOTs at National Center for Asphalt Technology (NCAT), 2012.

      Title:  Deployment of Innovative Asphalt Mixture Technologies

     Cooperative research study sponsored by Federal Highway Administration (FHWA) at National Center for Asphalt Technology (NCAT), 2012, RFA No. DTFH61-11-RA-00014, $3M. PI for “Pavement Preservation (PP) Specifications and Practices”.

     Title:  LTPP Computed Parameter: Dynamic Modulus

     Sponsored by: Federal Highway Administration (FHWA), September 1, 2007-April 30, 2009.

     Title:  Nondestrcutive Evaluation of Asphalt Pavements Using Impact Resonance Testing

     Sponsored by Federal Highway Administration (FHWA) at North Carolina State University, 2006.