This synthesis explores the state-of-the-knowledge and state-of-the-practice regarding the latest updates on polymer-modified bitumens (PmBs). The information in this study was gathered from a thorough review of the latest papers in the literatures related to modified bituminous materials, technologies, and advances. For this purpose, the paper is presented in two principle sections. In the first part, the bitumen itself is investigated in terms of chemical structure and microstructural systems. In the second part, the paper focuses on bitumen modification from different aspects for assessing the effectiveness of the introduced additives and polymers for enhancing the engineering properties of bitumen in both paving and industrial applications. In conclusion, the knowledge obtained in this study has revealed the importance of the chemical composition of base bitumen for its modification. It can be declared that while some polymers/additives can improve one or some aspects of neat bitumen properties, they can lead to compatibility problems in storage and production. In this respect, several studies showed the effectiveness of waxes for improving the compatibility of polymers with bitumen in addition to some benefits regarding warm mix asphalt (WMA) production.

This review focuses on certain classes of organic compounds known variously in the specific literature of asphalt as adhesion promoters, antistripping agents, wetting agents, antistrips, or adhesion agents. These kinds of organic additives are currently formulated to enhance the bitumen coating of mineral aggregates and improve the workability of asphalt mixtures. In this review, the term “adhesion promoters” includes both synthetic organic compounds as well as those extracted from natural resources, mixed in trace amounts to bitumen. Their main role is to alter the interfacial energy, so that the presence of water, even in trace, does not weaken the bitumen-aggregate bond and tends to favor adhesion. The report also considers the chemical functionalities that play a predominant role in bonding, as well as the effects of surface modification of the aggregate due to the presence of adhesion promoters in pre-blended bituminous mixtures. Although bitumen is widely used in road pavement construction and the discussion is mainly addressed to the improvement of adhesion in road materials, adhesion and wetting properties can also represent a general issue in various bitumen-based industrial products.

The objective of this study was to develop approximate relationships for prediction of the rheological properties and tensile strength of asphalt concrete with conventional bitumen binder to address the low-temperature cracking analysis. The parameters of modified Christensen–Anderson–Marasteanu model for relaxation modulus of bitumen were related with its penetration index and softening point by approximate formulas based on Van Der Poel's nomograph for determining bitumen stiffness. Hot mix asphalt relaxation function has been described by the Christensen–Bonaquist model. Hot mix asphalt tensile strength as a function of loading time and temperature was related to the bitumen stiffness by equation based on Heukelom's data and the Molenaar-Li empirical formula. The strength of hot mix asphalt has been also studied by performing tensile tests at constant strain rate and temperatures. The results were analysed considering the calculated stress increase with temperature drop at various cooling rates. Critical temperature was estimated from comparison of thermal stress and tensile strength of asphalt concrete at constant stress rate.

Bitumen, one of the by-products of petroleum industry processes, is the most common binder used in road pavements and in the construction industry in general. It is a complex organic mixture of a broad range of hydrocarbons classified into four chemical families, collectively known with the acronym SARA fractions, which include saturates, aromatics, resins and asphaltenes. Since the 1940s, researchers working on bitumen and the science behind its existence, nature and application have investigated the spatial organization and arrangement of several molecular species present in the binder. Therefore, several models have been proposed in the literature, and they are more or less corroborated by experimental studies, although most of them are model-dependent; for example, the structural investigations based on scattering techniques. One of the most popular models that has met with a wide consensus (both experimentally and of the modeling/computational type) is the one aiming at the colloidal description of bitumen’s microstructure. Other types of models have appeared in the literature that propose alternative views to the colloidal scheme, equally valid and capable of providing results that comply with experimental and theoretical evidence. Spurred by the constant advancement of research in the field of bitumen science, this literature review is aimed at providing a thorough, continuous and adept state of knowledge on the modeling efforts herein elaborated, in order to more precisely describe the intricacy of the bituminous microstructure. In this body of work, experimental evidence, along with details of bitumen’s microstructure (depicting the colloidal state of bitumen), is particularly emphasized. We will also try to shed light on the evolution of the experimental and theoretical results that have focused on the aspect of the association and aggregation properties of asphaltenes in various models and real systems.

Pavement roads and transportation systems are crucial assets for promoting political stability, as well as economic and sustainable growth in developing countries. However, pavement maintenance backlogs and the high capital costs of road rehabilitation require the use of pavement evaluation tools to assure the best value of the investment. This research presents a methodology for analyzing the collected pavement data for the implementation of a network level pavement management program in Kazakhstan. This methodology, which could also be suitable in other developing countries’ road networks, focuses on the survey data processing to determine cost-effective maintenance treatments for each road section. The proposed methodology aims to support a decision-making process for the application of a strategic level business planning analysis, by extracting information from the survey data.