This paper introduces bio-binder as a partial replacement for bituminous binder on highway and airport pavements. The proposed bio-binder is produced from the thermochemical conversion of swine manure. Bio-binder is then blended with virgin binder to produce bio-modified binder (BMB). In addition to being a renewable alternative for petroleum-based binder, the production and application of bio-binder may provide a solution for the management of swine manure waste. Furthermore, the application of bio-binder will improve asphalt binder's properties while reducing asphalt pavements' construction cost; the cost of bio-binder production is $0.54/gallon compared with that of asphalt binder $2/gallon. However, although the BMB has improved low-temperature properties, it may decrease the high-temperature grade of the binder. To address this concern, we in this paper investigate the feasibility of applying polyphosphoric acid into BMB. Using BMB in asphalt pavements can reduce mixing and compaction temperatures an...

Partial replacement of asphalt binder with bio-binder: characterisation and modification

This paper documents and discusses an investigation into the improved performance grading of asphalt binders that were used in the Canadian Strategic Highway Research Program (C-SHRP) pavement trial in Lamont, Alberta. Binders were assessed for their tendency to reversibly age at low-temperatures. While the correlation between cracking severity and regular AASHTO M320 and MP1a grades was weak (r 2=0.73 and 0.49, respectively), the predictive ability of the BBR method increased significantly when binders were tested after 1, 3 and 8 days of conditioning (r 2=0.94–0.97). Brittle and ductile fracture energies were measured in single-edge-notched bending (SENB) and double-edge-notched tension (DENT), respectively. In the brittle state, the SENB test revealed little difference between the binders. However, in the ductile state, the DENT test revealed significant differences between materials, with binders that showed the least amount of cracking having the highest works of fracture at 0°C.

Performance grading of the Lamont, Alberta C-SHRP pavement trial binders

Cette these s'inscrit dans le cadre d'une collaboration entre l'Ecole Nationale des TPE et les entreprises routieres APPIA et EUROVIA. La societe petroliere TOTAL a egalement ete associee a l'etude. Ce travail traite de l'analyse du comportement thermo-mecanique des enrobes bitumineux aux temperatures basses et intermediaires et vise a mettre en evidence les relations entre les proprietes des liants et des enrobes. Un large travail experimental de laboratoire a ete realise en vue de repondre a ces deux objectifs. Il s'agit notamment de mieux cerner les criteres existants de caracterisation des liants, voire d'en proposer de nouveaux, en relation avec le comportement en place des enrobes. Apres une etude bibliographique sur la rheologie et les proprietes thermo-mecaniques des bitumes, des mastics et des enrobes bitumineux, le travail experimental mene aussi bien dans le domaine des petites deformations que des grandes deformations, est expose. Le comportement a basse temperature des bitumes a ete evalue avec trois tests fondamentaux largement repandus : i)l'essai de module complexe, ii)l'essai de fluage au BBR, iii)l'essai de traction directe SHRP a vitesse de deformation constante et temperatures constantes. En outre, un nouvel essai de fissuration, consistant en un essai de flexion trois points sur eprouvettes de bitume preentaillees, a ete developpe a l'ENTPE. Les parametres de tenacite et d'energie de rupture des bitumes a basses temperatures ont pu etre determines en utilisant les hypotheses de la MLR (Mecanique Lineaire de la Rupture). Le comportement thermo-mecanique des enrobes bitumineux a basse temperature a ete etudie en realisant i)des essais de module complexe, ii)des mesures du coefficient de dilatation-contraction thermique, iii)des essais de traction a vitesses de deformation constantes, iv)ainsi que des essais de retrait thermique empeche. Tout d'abord, des liens pertinents entre les proprietes des liants et des enrobes, et des caracteristiques suffisamment discriminantes au regard des proprietes a basse temperature des enrobes ont ete mis en evidence. Ensuite, l'analyse a consiste a effectuer un travail de modelisation du comportement des liants et des enrobes, en petites et grandes deformations. Un modele rheologique monodimensionnel, qui consiste en une generalisation du modele analogique de Huet-Sayegh, a ete developpe dans le domaine des petites deformations. Ce modele, appele modele “2S2P1D”, permet de simuler correctement a la fois le comportement visco-elastique lineaire des bitumes et celui des enrobes bitumineux. A partir de ce modele, une transformation originale –independante du modele– permettant de predire le module complexe de l'enrobe a partir de celui du liant est proposee, puis validee. Enfin, la derniere partie de cette these est consacree a la loi generalisee monodimensionnelle “DBN” (Di Benedetto-Neifar) a partir de laquelle un programme a ete developpe sur l'interface Visual Basic du logiciel Excel. Ce programme constitue un outil simple de prevision du comportement de l'enrobe bitumineux sous diverses sollicitations (mecaniques et/ou thermiques). Ce modele rheologique permet de faire le lien entre les petites et les grandes deformations. Des simulations d'essais de traction a vitesses de deformation constantes, ainsi que des simulations d'essais de retrait thermique, monotones ou cycliques, sont enfin presentees.

https://tel.archives-ouvertes.fr/tel-00006050/document

COMPORTEMENT THERMOMÉCANIQUE DES ENROBÉS BITUMINEUX À BASSES TEMPÉRATURES. Relations entre les propriétés du liant et de l'enrobé

A new simple test device is proposed to directly measure the critical temperatures for thermal cracking of asphalt binders. Using the dissimilar coefficients of thermal expansion for asphalt binders and common metals, the asphalt binder cracking device (ABCD) was developed to simulate thermal cracking of asphalt pavement in the laboratory. The ABCD consists of a metal ring, a strain gauge glued to the inner side of the ring, an environmental chamber, and a data acquisition system. Development of thermal stress within the asphalt binder during cooling is monitored by the strain gauge and the cracking temperature can be directly determined from the strain reading. A simplified theoretical analysis of the ABCD shows that the effects of thermal contraction of the asphalt binder and aggregate and the elastic properties of aggregates on thermal cracking could be reproduced in an ABCD test by adjusting the specimen and device geometries. Preliminary test data support the concept of the ABCD.

Direct measurement of asphalt binder thermal cracking

Recently, researchers have made effective use of Black Space diagrams to model stiffness and relaxation changes relating to non-load-associated cracking. A Black Space-based approach to detecting cracking susceptibility is the Glover–Rowe (G-R) parameter, which requires complex modulus and phase angle at a particular temperature–frequency combination. This parameter is being evaluated as a replacement for low-temperature Superpave binder criteria. Primary objectives are to validate the G-R approach for binders with laboratory and field performance measurements; develop an indicator parameter for low-temperature cracking of mixtures using a combination of material properties; and develop alternate approaches to study mixture performance in Black Space. The G-R intermediate-temperature parameter shows mixed results with Black Space location for sections with thermal cracking. The G-R low-temperature parameter is used to determine a critical cracking temperature that agrees with Superpave binder specificatio...

Exploring low-temperature performance in Black Space

The main objective of this paper is to describe the development of a comprehensive semi-empirical mechanistic mode to determine the critical cracking temperature of asphalt pavements. This model uses stiffness data from the Bending Beam Rheometer (BBR) to predict thermal stress in binder. The thermal stress in the hot-mix pavement is computed using a damage transfer function called the Pavement Constant (PC). To determine critical cracking temperature , the pavement thermal stress is compared with the binder tensile strength measured using the Direct Tension Test (DTT). This model was used to develop a low-temperature criterion for use as a binder specification. In this specification, the low-temperature binder performance grade is determined by comparing the thermal stress in the pavement with the binder failure stress. If the binder failure stress exceeds the thermal stress at the specification temperature, the binder is considered a "pass." The semi-empirical model was calibrated using the binder properties and the hot-mix properties from the Lamont Test Road in Alberta, Canada. Further validation was obtained from analysis of the Elk County Test Road in Pennsylvania, as well as for two widely used polymer-modified asphalts with anecdotal, but extensive, performance data.

Mark J Sharrock

Papers

Predicting thermal cracking of pavements from binder properties: theoretical basis and field validation