# Design of Nonbituminous Binders for Road Application Using Vegetable Resources

## TL;DR

This paper introduces a sustainable, nonbituminous road binder made from vegetable resources as a replacement for petroleum-based bitumen.

## Contribution

A novel biobinder formulation using colophony resin ester, waste cooking oil, cellulosic pulp, and MDI is proposed for road applications.

## Key findings

- The biobinder formulation includes 27.22% oil, 67.76% rosin, 2.02% cellulosic pulp, and 3% MDI.
- MDI acts as a compatibilizer via urethane/amide linkages between components.
- The biobinder meets European and American standards for asphalt binders.

## Abstract

This work proposes novel biobinders
as a more sustainable alternative
to traditional bituminous products. They should be able to fully replace
petroleum bitumen as binders of aggregates in road asphalts. Colophony
resin ester (R), waste cooking oil (O), and cellulosic pulp (CP) were
used as the main components of biobinders. Furthermore, the addition
of a small amount of a reactive isocyanate-terminated prepolymer (MDI)
is required. Binder formulation and processing were assessed by a
comprehensive rheological, microstructural, and technological characterization
to understand the role of each component in the final material properties.
Rosin was a structuring agent, oil acted as a plasticizer, and the
cellulosic pulp increased the material's softening point. MDI
played
a key role as a compatibilizer via urethane/amide linkages between
the isocyanate groups of MDI and the OH/COOH groups present in the
other three components. As a result, a biobinder formulation was proposed
to replace bituminous binders, which was composed of 27.22 wt % oil,
67.76 wt % rosin, 2.02 wt % cellulosic pulp, and 3 wt % MDI. They
should be added following the order R > O > MDI > CP and
processed
at 150 °C. Finally, its potential as an asphalt binder was evaluated
according to European and American standards accepted for commercial
bituminous products.