Low-temperature properties of plant-produced RAP mixtures in the Northeast

The impact of reclaimed asphalt pavement (RAP) materials on pavement performance is an important topic of study in the industry due to environmental and cost benefits. The primary concern for increasing allowable RAP percentages in hot mix asphalt relates to the presence of aged materials, which may embrittle the mixture and decrease cracking resistance. Low-temperature cracking is a major distress in cold temperature climates, such as the Northeastern United States. Currently, there are several procedures to analyse low-temperature performance of asphalt binders and mixtures. However, these methods use different starting (initial) temperatures and cooling rates that may not represent actual field temperatures and cooling rates. This paper presents the results of a study on low-temperature performance of plant-produced RAP mixtures. Eighteen mixtures from three states were tested with varying RAP contents (0–40%) and different virgin binder grades. The objectives of the study were to: (1) evaluate the impact of cooling rate and starting temperature on the critical cracking temperature of RAP materials; (2) evaluate the impact of RAP content on the low-temperature properties of mixtures; (3) evaluate the benefit of using softer virgin binder grades to mitigate the impact of the aged RAP binder in the mixture; and (4) to compare the low-temperature cracking properties determined from different mixture and binder tests. Based on the results, warmer starting temperatures and faster cooling rates result in warmer critical cracking temperatures for all mixtures. Through use of the uniaxial thermal stress strain test, it was found that the addition of RAP alters fracture behaviour from ductile failure towards a brittle failure. Based on results from the indirect tensile test, tensile strength increases with RAP content. However, due to a faster-building thermal stress, warmer critical cracking temperatures result. It was also determined that degree of blending may impact the effectiveness of using softer binder grades at higher RAP percentages to improve low temperature cracking resistance. The data also show that analysis procedure and test protocols can have a profound effect on critical cracking temperature. The conclusions presented reinforce the need for more accurate representation of RAP materials, and careful selection of analysis parameters.

[1]  S. Huang,et al.  Rubber Concentrations on Rheology of Aged Asphalt Binders , 2008 .

[2]  Nicholas W. Tschoegl,et al.  The Phenomenological Theory of Linear Viscoelastic Behavior: An Introduction , 1989 .

[3]  Matthew W Witczak,et al.  New Predictive Models for Viscosity and Complex Shear Modulus of Asphalt Binders , 2007 .

[4]  Nathan E. Morian,et al.  Low Temperature Characterization of Asphalt Mixtures by Measuring Visco-Elastic Properties under Thermal Loading , 2013 .

[5]  Glaucio H. Paulino,et al.  Development of a Single-Edge Notched Beam Test for Asphalt Concrete Mixtures , 2005 .

[6]  Numerical computation of convolution integral for the linear viscoelasticity of asphalt concrete , 2006 .

[7]  Richard Schapery,et al.  A theory of crack initiation and growth in viscoelastic media , 1975 .

[8]  R. Roque,et al.  A mechanics-based prediction model for thermal cracking of asphaltic concrete pavements , 1994 .

[9]  T S Vinson,et al.  Low temperature cracking resistance of asphalt concrete mixtures , 1993 .

[10]  R. Roque,et al.  EVALUATION OF EMPIRICAL AND THEORETICAL MODELS TO DETERMINE ASPHALT MIXTURE STIFFNESSES AT LOW TEMPERATURES (WITH DISCUSSION) , 1996 .

[11]  K Close,et al.  AMERICAN ASSOCIATION OF STATE HIGHWAY AND TRANSPORTATION OFFICIALS COMPUTER SYSTEMS INDEX , 1976 .

[12]  Imad L. Al-Qadi,et al.  Simple method to obtain asphalt binders low temperature properties from asphalt mixtures properties , 2005 .

[13]  R. Taylor,et al.  Thermomechanical analysis of viscoelastic solids , 1970 .

[14]  N. Gibson,et al.  Effect of long-term ageing on RAP mixtures: laboratory evaluation of plant-produced mixtures , 2013 .

[15]  S. W. Park,et al.  A viscoelastic constitutive model for particulate composites with growing damage , 1997 .

[16]  Ghassan R. Chehab,et al.  Viscoelastoplastic Continuum Damage Model Application to Thermal Cracking of Asphalt Concrete , 2005 .

[17]  Rebecca S McDaniel,et al.  Investigation of Low- and High-Temperature Properties of Plant-Produced RAP Mixtures , 2012 .

[18]  Thomas Bennert,et al.  Performance characteristics of plant produced high RAP mixtures , 2012 .

[19]  Jo Sias Daniel.  Development of a simplified fatigue test and analysis procedure using a viscoelastic, continuum damage model and its implementation to WesTrack mixtures , 2001 .

[20]  S. W. Park,et al.  Methods of interconversion between linear viscoelastic material functions. Part I-a numerical method based on Prony series , 1999 .

[21]  Glaucio H. Paulino,et al.  Investigation of Low Temperature Cracking in Asphalt Pavements, National Pooled Fund Study - Phase II , 2012 .

[22]  D. Christensen.  ANALYSIS OF CREEP DATA FROM INDIRECT TENSION TEST ON ASPHALT CONCRETE , 1998 .

[23]  G. Huber,et al.  Investigation of Properties of Plant-Produced Reclaimed Asphalt Pavement Mixtures , 2007 .

[24]  David H. Allen,et al.  A THREE-DIMENSIONAL FINITE ELEMENT FORMULATION FOR THERMOVISCOELASTIC ORTHOTROPIC MEDIA , 1997 .

[25]  M W Witczak,et al.  DEVELOPMENT OF A GLOBAL AGING SYSTEM FOR SHORT AND LONG TERM AGING OF ASPHALT CEMENTS (WITH DISCUSSION) , 1995 .

[26]  Hyunwook Kim,et al.  Simulation of Fracture Behavior in Asphalt Concrete Using a Heterogeneous Cohesive Zone Discrete Element Model , 2008 .

[27]  M I Darter,et al.  THERMAL EXPANSION-CONTRACTION OF ASPHALTIC CONCRETE , 1968 .

[28]  Henrique M Reis,et al.  Effects of Recycled Asphalt Pavement Amounts on Low-Temperature Cracking Performance of Asphalt Mixtures Using Acoustic Emissions , 2011 .

[29]  Y. Richard Kim,et al.  A viscoelastic continuum damage model and its application to uniaxial behavior of asphalt concrete , 1996 .

[30]  Michael Boyle.  Materials-Related Forensic Analysis and Specialized Testing: Laboratory Evaluation of Hot-Mix Asphalt (HMA) Mixtures Containing Recycled or Waste Product Materials Using Performance Testing , 2005 .

[31]  Eric B. Becker,et al.  A multidata method of approximate Laplace transform inversion , 1970 .

[32]  J. M. Jiménez-Mateos,et al.  Characterization of petroleum bitumens and their fractions by thermogravimetric analysis and differential scanning calorimetry , 1996 .

[33]  N. Tschoegl.  The Phenomenological Theory of Linear Viscoelastic Behavior , 1989 .

[34]  Jo Sias Daniel,et al.  Can More Reclaimed Asphalt Pavement be Added? , 2010 .