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The streets that did not have a current chip seal were evaluated using the nuclear density gauge <br />to measure density, then field permeability with NCAT Field Permeameter tester, sample coring, <br />lab permeability ASTM PS 129-1 and in place air voids same as chip sealed streets. <br />Non chip sealed streets were evaluated in hopes of determining a method to predict the <br />possibility of stripping of the street after it was chip sealed. Task 5 will analyze the data <br />collected develop recommendations on how to evaluate existing streets for a chip seal. <br />k _ al In h1 <br />At h2 <br />Where: <br />k coefficient of permeability, <br />cm/sec <br />a inside cross -sectional area of <br />standpipe, cm2 <br />1 thickness of test specimen, cm <br />A cross -sectional area of <br />specimen, cm2 <br />hi hydraulic head on specimen at <br />time, ti <br />h2 hydraulic head on specimen at <br />time, t2 <br />Figure 16 Lab Permeameter <br />Conclusions: <br />Field testing: Based on ease of use and quick results, the nuclear density gauge is the best test <br />method to used test and evaluates a large number of locations. The negative to this method of <br />evaluation is the gauge requires a trained and licensed operator and has special storage <br />requirements. The NCAT Field Permeameter tester is a slow test taking over 20 minutes to <br />complete on test location in field. The result can vary from operator to operator. Some <br />pavement surfaces are more difficult to seal the tester to which can give false readings. One <br />interesting observation was that in areas of stripping under chip seal, we had difficulty in <br />obtaining cores. The action of the core barrel and water in many cases completely destroyed the <br />remaining pavement. Areas close to site of destroyed cores had air voids up to 11% this leads us <br />to believe that areas with worst stripping have even higher voids. See figure 4 & 5 below. <br />C-3 <br />