AASHTO TP 141-20 PDF Download

AASHTO TP 141-20 is a provisional standard method of test that provides guidelines for determining the indirect tensile Nflex factor of asphalt mixtures. The purpose of this standard is to assess the cracking resistance of asphalt mixtures, specifically for load-related cracking in asphalt pavement layers. The method involves using the indirect tensile (IDT) geometry at 25 degrees to measure the toughness and brittleness slope of the asphalt mixture.

The toughness is calculated by measuring the area beneath the stress-estimated strain data, while the brittleness slope is determined by analyzing the post-peak stress-estimated strain rate. These values are then used to calculate the Nflex factor, which serves as an indicator of the asphalt mixture's susceptibility to load-related cracking.