GRADING & RELATED ISSUES WORKSHOP : AGGREGATES DEFINING THE ISSUES 5 FEBRUARY 2014

Outline Background Defining the issues

Background Revision of the TMH1 - financed by SANRAL and carried out under the auspices of the Materials Testing Committee (MTC) of the Road Materials Committee (RMC). The revision of TMH1 to SANS3001 necessitated the use of new sieve sizes according to ISO Standards The grading envelope (spec) was not changed in an attempt not to affect the outcome of test results as a grace period was allowed for labs to still use THM1 sieves

Defining the Issues Continuous graded aggregate mixes not affected by implementation of new sieve sizes for grading analysis New grading limits determined through interpolation Example of new specifications according to SANS3001

New Grading Spec for Asphalt

Defining the Issues Single-sized aggregate was affected by implementation of new sieve sizes for grading analysis New grading limits determined through interpolation, BUT Resulted in stricter specifications in order to maintain the same grading envelope as for TMH1 Example of new specifications according to SANS3001

New Grading Spec for Single Sized Aggregate

Proposed Solution Single-sized aggregate: TMH1 envelope to be applied for SANS3001 sieves

Impact of proposed changes Slightly higher ALD’s which is more beneficial for surfacing seals as it allows for higher binder applications Less material wastage

Questions