Download Free Evaluation Of Polymer Modified Asphalts For Seal Coal Applications Book in PDF and EPUB Free Download. You can read online Evaluation Of Polymer Modified Asphalts For Seal Coal Applications and write the review.

The Department desires to evaluation asphalt modifiers to enhance aggregate retention for seal coats. We have been looking at various asphalt modifiers that in past years have included latex and neoprene type additives. Recently, the asphalt industry has developed various polymer additives that are marketed to solve many of the present problems. These additives are promoted to give "rubbery" characteristics to the asphalt binder materials during the hot pavement surface temperature periods of the summer months when other asphalt binders will become soft and allow loss of the aggregates. These additives are usually costly and increase the project costs significantly. Therefore, it is important to evaluate the cost-effectiveness of their use. After one year of service, the control sections have suffered significant loss of the aggregate and the sections are flushed and asphalt is tracking in the direction of traffic. The polymer modified sections are in better shape than the control sections. All have suffered the usual snowplow damages, such as abrasion of the aggregate by the sliding snowplow shoes and "scuffing" by the bouncing snowplow blade.
Following the five-year study performed to investigate the behavior of binders and asphalt mixtures containing polymer modifiers, it was determined that an insufficient amount of time had elapsed to allow any determinations to be made based upon the special field test sections. The study reported herein was to extend that initial time and to study in depth those special test sections, using visual observations coupled with resulting tests performed on samples extracted from the sections and comparisons with the original data developed in the original research. The research includes laboratory testing of field samples, determining the aging effect on the control and modified binders and corresponding effect on the mixtures, and visual evaluations. Retained samples of the original asphalts were also evaluated for potential performance as determined by the performance-based asphalt binder specification developed by the Strategic Highway Research Program. Four hot mix pavement field projects were constructed in the Tyler, Lufkin, San Antonio, and Childress Districts (10, 11, 15, and 25, respectively), and two seal coat projects were placed in the Odessa and Bryan Districts (6 and 17).
Polymer modified asphalts have recently been the focus of much attention in the U.S. due to claims that polymer additives will lengthen the life of an asphalt pavement. Much of the published research on this topic has been concentrated on the effects of polymer modifiers on binder and mixture properties. The goal of this testing is to predict from laboratory testing the actual field performance of an asphalt concrete. Over the years, specifications have been developed for conventional asphalts that allow pavement performance to be predicted from certain binder tests. These conventional binder tests do not fully address the special characteristics of polymer modified asphalt binders and need revision to be an effective tool in predicting pavement service life. This paper presents the findings of a two-part laboratory research program intended to relate binder and mixture properties of polymer modified asphalts. The preliminary testing involved five asphalt binder types and a variety of binder and mixture tests. Promising test procedures were further investigated in the final testing program where ten asphalt binders were examined. Simple linear regression was used to determine the strength of a relationship between pairs of binder properties and mixture properties. The preliminary testing showed penetration, toughness and tenacity, and force ductility to have the most promise in predicting mixture performance. The final testing contained enough data to be analyzed with both simple linear regression and multiple regression. Penetration, toughness and tenacity, force ductility again were the test procedures that had binder properties that correlated well with mixture properties.
The primary objective of this project was to study selected Superpave tests on asphalt binders to evaluate their applicability to polymer modified asphalts. Other tasks included the determination of experimental techniques to evaluate the concentration of polymer additives in polymer modified asphalts and the evaluation of rutting potential of roadway cores and gyratory specimens in the Asphalt Pavement Analyzer (APA), a commercial version of the Georgia loaded wheel tester.
Asphalt modification using polymeric additives derived from solid wastes, i.e. polyolefins, is reported. Chlorination of polyethylene can be controlled to produce semicrystalline polymeric additives. Differential scanning calorimetry can be used to determine the asphalt crystallinity and the distribution components among phases in asphalt/polymer blends. To enhance the resolution of a given thermogram, a several-step annealing process is required to experimentally realize a near-equilibrium state. Introducing chlorine atoms on polyethylene chains can improve the compatibility of the asphaltlpolymer blends by adjusting the interaction between the components of asphalt and polymer. Maleation of polyolefins at very low levels (one to two percent) is an effective means for enhancing the polarity of the additive without influencing the degree of crystallization.