Industry Applications
How to Improve the Softening Point of Asphalt?
The softening point of emulsified asphalt is essentially the softening point of the base asphalt, and different asphalts have different softening points.
To increase the softening point, modification methods can be used.
The simplest method is to add a modifier—polyethylene wax—to the emulsified asphalt, which can adjust the asphalt softening point. Polyethylene wax can significantly reduce asphalt penetration and increase the asphalt softening point and ductility.
As the polyethylene wax content increases from 8% to 16%, the PI value of the modified asphalt increases from 0.939 to 1.877, belonging to sol-gel type asphalt. It exhibits some elasticity and less obvious thixotropy, with significantly improved high-temperature rutting resistance and low-temperature cracking resistance.
When the polyethylene wax content increases to 20%, the PI value of the modified asphalt increases to 2.407, exceeding +2.0, belonging to gel-type asphalt. It has obvious elastic effects, with strong elasticity and thixotropy.
Through the study on the dynamic rheological properties of modified asphalt, it is found that polyethylene wax increases the complex shear modulus (G*), storage modulus (G') and loss modulus (G''), while decreases the phase angle (δ). At the same time, the rutting resistance factor G*·sinδ⁵⁻¹ of modified asphalt is improved to a certain extent, and the rutting resistance is enhanced.
A study on the viscosity (η) of base asphalt and modified asphalt at different temperatures in the high-temperature region shows that polyethylene wax can significantly increase the viscosity of asphalt, enhance the ability of asphalt to resist flow, and thus achieve the purpose of improving its rutting resistance.
