The Influence of a Polymer Powder on the Properties of a Cold-Recycled Mixture with Foamed Bitumen

Abstract

The paper investigates the influence of redispersible polymer powder (RPP) on the physical and mechanical properties of a cold-recycled mixture with foamed bitumen (CRM-FB). Four types of RPP with a varied chemical base were used: VA-VeoVA, VA-VeoVa-Ac, EVA and VA/VV/E/Ac. The polymer powder-modified cold recycled mixture with foamed bitumen, (P)CRM-FB, was composed of 45.8% reclaimed asphalt pavement (RAP), 45.8% natural aggregate (VA), 3.0% Portland cement CEM I 42,5R, 3.0% foamed bitumen 50/70 and 3.0% RPP, all dosed by weight. The reference mixture, (R)CRM-FB, served as a reference point for comparison. It was found that RPP improved the workability of the CRM-FB mixture. This results in a reduced number of compaction cycles and lower energy needed to obtain the air void content as in the reference mixture. In addition, the RPP modifier markedly increased the CRM-FB mixture cohesion (ITSDRY) and strength, by approximately 40–70%, depending on the RPP used. These findings are particularly important for CRM-FB mixtures designed for road bases. The present investigations confirmed the improvement of the CRM-FB mixture parameters after the modification with RPP, regardless of the powder type used.

Effects of Portland Cement and Polymer Powder on the Properties of Cement-Bound Road Base Mixtures

“…Examples of the powder microstructure are shown in Figure 1 , whereas the chemical composition of the polymer powder is shown in Table 3 . Detailed information on the polymer powder used in this study can be found elsewhere [ 26 ].…”

“…Bituminous binders reduce the stiffness of the mixture while maintaining proper cohesion and increased deformability. However, preliminary research results [ 26 ] show that the polymer powder used in cement- and foamed bitumen-bound mixtures provides high cohesion without increasing the stiffness.…”

“…A typical redispersible polymer powder—ethylene-vinyl acetate (EVA)—was used in the study. The copolymer of ethylene and vinyl acetate was selected based on the authors’ preliminary findings concerning the effects of various polymers on the properties of cold recycled mixtures with foamed bitumen [ 26 ]. The use of EVA copolymer allowed achieving high cohesion at stiffness maintained at the same level [ 26 ].…”

“…The copolymer of ethylene and vinyl acetate was selected based on the authors’ preliminary findings concerning the effects of various polymers on the properties of cold recycled mixtures with foamed bitumen [ 26 ]. The use of EVA copolymer allowed achieving high cohesion at stiffness maintained at the same level [ 26 ]. Used in the alkaline environment of cement pastes, EVA was found to minimize the detrimental saponification reaction [ 27 ].…”

Properties of a Three-Component Mineral Road Binder for Deep-Cold Recycling Technology

“…Permanent deformation generated in the foundation or mineral base layers is the distress that requires extensive maintenance. One of the techniques recommended for eliminating the cause of permanent deformation is the environmentally friendly deep-cold recycling technology (CR) [ 1 , 2 , 3 , 4 ]. Pavement lower layers produced using CR are semi-rigid base courses that are typically made with bituminous binders (such as emulsion or foamed bitumen) and mineral binders (Portland cement, hydrated lime, fly ash, or cementitious dusts) [ 5 , 6 ].…”