The Effect of Polymer Powder on the Cracking of the Subbase Layer Composed of Cold Recycled Bitumen Emulsion Mixtures.

Jakub Krasowski,Przemysław Buczyński,Marek Iwański

doi:10.3390/ma14195867

Abstract

The research was aimed at assessing the effect of the redispersible polymer powder on the fracture resistance of a subbase made of a mineral–cement mixture with a bitumen emulsion. The test was performed at two temperatures, i.e., 0 °C and 20 °C. The prepared mixtures differed in the content of cement, asphalt emulsion, and polymer modifier. Cement and redispersible polymer powder were dosed in 1.5% steps from 0.5% to 3.5% while the amount of bitumen emulsion ranged from 0.0% to 5.0%. The SCB (semi-circular bending) tests carried out in the laboratory showed the dependence of the influence of the amount of binder and polymer modifier on the fracture resistance of the recycled subbase. Mixes containing a polymer modifier in their composition are characterized by a much higher resistance to cracking than traditional mineral–cement–emulsion mixtures. An example is the doubling of the framework’s fracture toughness (KIC) when the amount of the polymer modifier is increased from 0.5% to 2.0% with a constant cement content of 0.5%. The obtained results (KIC) in this case were 2.90 and 5.81. The key is the right ratio of polymer powder and cement in the base composition.

Highlights

Subbases with hydraulic binders are commonly used in pavement structures
It seems to be important to test the fracture resistance of mixtures made using the deep cold recycling technology, and of all materials used in the road pavement layers [16,17,18]
It is worth mentioning bound mixes used as Cement Bound Mixtures (CBM)

Summary

Introduction

Subbases with hydraulic binders are commonly used in pavement structures Examples of such materials include, among others, mixtures made using the deep cold recycling technology. It is extremely important for the industry to precisely identify the stiffness modulus of recycled mixtures This parameter is strongly affected by the quantity and quality of the hydraulic binder added to the mix, as well as the content of binders in the subbase. It seems to be important to test the fracture resistance of mixtures made using the deep cold recycling technology, and of all materials used in the road pavement layers [16,17,18] It is worth mentioning bound mixes used as Cement Bound Mixtures (CBM). Despite the fact that they can constitute a permanent and load-bearing subbase, the risk of fracturing is even higher

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Conclusion