VERIFICATION OF THE PERFORMANCE OF THERMOPLASTIC PLANT MIX ADDITIVE USED TO PRODUCE BRIDGE DECK WATERPROOFING MATERIALS

摘要

ABSTRACTPlant mixed modifier (PMM) has been used for the past 25-years to produce waterproofing asphalt materials forbridge deck applications as a polymerized "Dry Mix" modifier. These offer significant advantages overconventional polymer modified binders (PMBs) since much high polymer loading can be used in the final materialwithout the risk of storage separation and/or pumping and handling issues associated with these high polymer loads.However, with the advent of Superpave it has become the norm for many specifying agencies to include theSuperpave binder specification tests as "performance related" controls for the specification. Unfortunately, withplant mix additives it is not possible to obtain a sample of the binder in the conventional manner that occurs with theuse of PG binders thus making this route for quality assessment not feasible. Nevertheless, it is possible to evaluatemixture performance using a suite of tests that relate to low-temperature cracking, fatigue performance andpermanent deformation – thus capturing the same end performance requirements considered in the binder but bytesting the mixture. Conceptually, this is better since mix tests should more closely relate to field performance thanbinder tests. The use of these tests to develop rational specification parameters is discussed for a bridge-deckthermoplastic PMM water proofing material which is used by various state DOTs and other agencies.Recommendations are made that could form the basis for a performance related specification for these bridge deckwaterproofing materials utilized as an alternative to torch or spray applied systems, epoxy overlays or latex modifiedconcrete overlays.