Quick-traffic slurry surfacing mix with orthophosphoric acid

Bitumen emulsions for slurry surfacing mix technology using oxidized bitumen and hydrochloric and orthophosphoric acids on laboratory DenimoTech bitumen-emulsion plant are made in the work. Methylene blue adsorption index of granite aggregate for use in slurry surfacing mix was investigated. Comparatively mix time and cohesion strength build-up of selected compositions slurry surfacing mix with hydrochloric and orthophosphoric acids depending on the variable content of bitumen emulsion. The advantage of using orthophosphoric acid in slurry surfacing mix according to the cohesion strength build-up criterion has been proved. The importance of correct distribution of bitumen drops in the emulsion was confirmed using a sedimentograph Mastersizer 2000. Two emulsions of the same component composition were compared, which differed in particle size. It has been established that it is not possible to design a slurry surfacing mix using the mix time criterion with the help of coarse bitumen emulsion

Adhesion in Bitumen/Aggregate System: Adhesion Mechanism and Test Methods

A literature review of the five main theories describing the interaction mechanisms in the bitumen/aggregate system was conducted: theory of weak boundary layers, mechanical theory, electrostatic theory, chemical bonding theory, and thermodynamic theory (adsorption theory). The adhesion assessment methods in the bitumen/aggregate system are described, which can be divided into three main groups: determination of adhesion forces for bitumen with different materials, determination of bitumen resistance to the exfoliating action of water with different materials, and determination of adhesion as a fundamental value (contact angle measurements, interfacial fracture energy, adsorption capacity and others). It is proposed to evaluate the quality of adhesive interaction in the bitumen/aggregate system in two stages. The authors recommend using the adhesion determination methods for these two stages from the second group of methods the determination of bitumen resistance to the exfoliating action of water with different materials. In the first stage, the adhesion in the bitumen/aggregate system is determined by an accelerated technique in which the used bitumen binder and mineral material are considered as test materials. After the first stage, there are positive results in the second tests on compacted mixtures (indirect tensile strength test, Modified Lottman indirect tension test, immersion-compression test, and Hamburg wheel tracking test)