Evaluation of Limestone Filler in Gravel Mixtures "Asphaltic Concrete", R-228, 1968

(1968) Evaluation of Limestone Filler in Gravel Mixtures "Asphaltic Concrete", R-228, 1968. Transportation, Department of

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Abstract

This study was designed to provide background information on asphaltic concrete mixtures peculiar to northwest Iowa. This background is necessary to provide the basis for future specifications. There were several projects let in 1967 involving l", 3/4" and 3/8" mixes of Type "B'' asphaltic concrete which specified in part, II Not less than 40% of the material passing the No. 200 sieve shall be pulverized limestone or mineral filler, but in no case shall the per cent of pulverized limestone or mineral filler passing the No. 200 sieve be less than 2%. No credit will be allowed for limestone in gravel - II Northwest Iowa has no suitable limestone or mineral filler locally available. As a result, this material has to be imported, raising the cost of the mix approximately twenty-five cents per ton. The purpose of this study, therefore, was designed to compare some original job mix samples with alternate mixes from the same local material, but without the addition of pulverized limestone or mineral filler. Since the filler from the crushed gravel does not have the same crushing characteristics or sieve analysis as the pulverized limestone or mineral filler, they could not be compared on an equal percentage basis. Therefore, the alternate mixes were made to conform to the following proposed specification, "No less than 40% of the material passing No. 200 sieve shall be pulverized limestone or mineral filler or a 100% crushed gravel, but in no case shall the per cent of pulverized limestone or mineral filler or a 100% crushed gravel passing the No. 200 sieve be less than 2%."

Item Type: Departmental Report
Keywords: Admixtures, Asphalt concrete, Asphalt mixtures, Gravel, Limestone fillers
Subjects: Transportation
Transportation > Materials
Transportation > Materials > Gravel and aggregates
Transportation > Roads and highways
Transportation > Research
Transportation > Research > Concrete
ID Code: 16607
Deposited By: Iowa DOT Library
Deposited On: 24 Apr 2014 11:44
Last Modified: 07 Jan 2015 21:15
URI: http://publications.iowa.gov/id/eprint/16607