Asphalt mixtures that fail to meet specifying agency requirements for TSR need to be completely redesigned.

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Tensile Strength Ratio (TSR) is a measure of how resistant an asphalt mixture is to moisture damage. It compares the strength of a conditioned (wet) sample to an unconditioned (dry) sample. A low TSR means the mix is losing strength when exposed to moisture, which can lead to stripping and reduced durability.

If a mix doesn’t meet the TSR requirement, you don’t automatically redesign the entire mix from scratch. The typical approach is to make targeted adjustments to improve moisture resistance and then retest. This can include changing the asphalt binder grade or adding anti-strip agents, adjusting binder content, modifying aggregate sources or cleanliness, altering the aggregate gradation or RAP content, or tweaking production or process factors. Only after these focused changes fail to bring TSR into spec would a more extensive redesign be considered.

So, the statement that failing TSR requires a complete redesign is not accurate.