The short answer is that contractors that are counting on RAS (Recycled Asphalt Shingles) contributing to effective asphalt content in the HMA (Hot Mix Asphalt) they produce are fooling themselves and their customers by recycling process including the Sydney Rubbish Removal services for the materials. The RAS will definitely add to AC (Asphalt Cement) content in their HMA when tested in the ignition furnace. The problem is that the AC in the RAS does not liquefy at HMA mixing temperatures. The RAS AC just acts as black rocks in the HMA and not as a binder.
There have been many failures in HMA pavements due to this. The liquefying temperature of RAS AC is extremely high, higher than what can be done in HMA plants.
There are many rejuvenating products on the market that promise to soften the RAS AC in the HMA mixing process. However, the HMA mixing process only lasts about 30 seconds and the rejuvenating agent, when introduced in the process, does not target the RAS specifically.
The rejuvenator sales people will show laboratory tests that when their product is combined with RAS AC it will result in a paving grade AC. Applying this laboratory analysis to real world conditions is a fallacy. There is not the same interaction in an HMA plant with the rejuvenating agent as there is in the laboratory specimens.
The Asphaltica process specifically targets the RAS AC with a rejuvenator and has a dwell time of at least 24 hours. A far superior process that results in superior HMA.
Pretreatment of RAS BEFORE adding it to the HMA allows time for the osmotic reaction of the oxidized bitumen to occur. That eliminates secondary absorption causing problems while the HMA is in service.