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Cold bituminous materials, most commonly grave emulsion and stabilised wet-mix macadam, are manufactured using granular materials, added water and bitumen emulsion.
The unbound granular material should be checked for grading, mechanical strength and plasticity (1 sample per 500 tonnes). The quality of the fines fraction of the aggregate can be assessed using the methylene blue value and sand equivalent tests.
The ability of the bitumen to coat the stone and resist stripping in the presence of water is assessed using the duriez test procedure. In the duriez test, the relative compaction, resistance to compression, and wet/dry strength ratio of the cold mixed material are checked for compliance with the relevant mix design specification.
The residual binder content and aggregate grading of cold mixes should be checked regularly. Initially, a rate of sampling of 1 sample per 100 tonnes is recommended, this being reduced when a satisfactory level of control has been achieved.
The compaction density achieved on site can be monitored using the sand replacement test and nuclear density gauge.
Highway Testing Laboratory Ltd. can sample, test and certify the quality of cold bituminous materials for use in road construction. The range of tests which we perform are listed below:
Cold Bituminous Material Tests:
Cold Bituminous Material
Sampling of Materials
Soaked Ten Percent Fines Value (TFV)
Methylene Blue Test
Sand Equivalent Test
Binder Content and Aggregate Grading
Sand Replacement Test
Nuclear Density Gauge Testing
The standard tests for assessing cold bituminous materials are performed in accordance with the following:
B.S. 812 "Testing Aggregates"
B.S. 598 "Sampling and Examination of Bituminous Materials"
French standard NF P 98-251-4 "Duriez Test on Bitumen Emulsion-Aggregate Mixes"
The Department of the Environment "Specification for Road Works"
The NRA "Provisional Specification for Stabilised Wet-Mix Macadam"