Tender Asphalt Mixes - Causes and Cures
In the Tender Zone, the mix tends to shove and push under the steel wheel. You can roll mix in the Tender Zone, but a pneumatic roller is necessary. The rubber tires do not shove the mix in the Tender Zone.
Tender Mixes - Pavement Interactive
A tender mix is an internally unstable mix that tends to displace laterally and shove rather than compact under roller loads. Internal mix stability is a function of asphalt binder viscosity and aggregate gradation and shape. Mix tenderness is usually one of two varieties (TRB, 2000 ): High temperature tenderness. At high temperatures some mixes may not be viscous enough to support roller loads without laterally displacing.
How To Compact Tender Asphalt Mixes - For Construction Pros
Hot mix asphalt mixtures that have tender characteristics still have to be compacted to a minimum level of density or a maximum level of air void content. Because of the lack of internal stability in the mix, however, the compaction of a tender mix is often very difficult.
When tender mixes occur, typically, the mix can be rolled for 1-2 or more passes with a steel wheel roller before the mix begins to move laterally. After a few passes with steel wheel rollers and after the mix has had an opportunity to cool, the mix begins to act tender under the steel wheel rollers.
Compaction of Tender HMA Mixtures
“New” Tender Mixes •Can happen to mixes designed for high traffic –Particularly coarse-graded mixtures •Usually occurs at an intermediate temperature (roughly between 260 and 200 F) after breakdown rolling •Not readily apparent during mix design or production QC testing
Compacting Hot-Mix Asphalt Pavements: Part II | Roads & Bridges
of density with a tender mix-the rollers can't compensate for a poor mix design. When a tender mix is encountered, the mix design-not the compaction process-should be changed. Until the mix design can be changed, often the best way to compact a tender mix is to use a pneumatic-tire roller in the breakdown position, directly behind the paver.
Stone Mastic Asphalt - Civil Engineering
SMA is best explained as two-component hot mix asphalt HMA which comprises a coarse aggregate skeleton derived from a gap-graded gradation and a high bitumen content mortar. Since 1960s, Stone Mastic Asphalt (SMA) pavement surfaces have been used successfully in Germany on heavily trafficked roads.
Technical Report Documentation Page
Durability of Hot-Mix Asphalt Durability of an asphalt mixture refers to the ability of the mixture to retain the original properties. These include the resistance to load and abrasion. Resistance to load can be impaired when: 1. The asphalt becomes hard and brittle and thus cannot withstand strains without fracturing. 2.
Division of Maintenance - Pavement
Guidelines for Identifying and Repairing Localized Areas of Distress in Asphalt Concrete Pavements Prior to Capital Preventive Maintenance or Rehabilitation Repairs; Pavement Tapers & Transitions (Interim) Shoulder Backing Guidelines; Paving over Existing Striping, Markings, and Pavement Markers; Rubberized Hot Mix Asphalt (RHMA)
Superpave Mix Design - Pavement Interactive
Although the new methods of mixture performance testing have not yet been established, the mix design method is well-established. Superpave Procedure. The Superpave mix design method consists of 7 basic steps: Aggregate selection. Asphalt binder selection. Sample preparation (including compaction). Performance Tests. Density and voids calculations.