GRADING RELATED ISSUES WORKSHOP AGGREGATES DEFINING THE ISSUES

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

Outline q Background q Defining the issues

Background Revision of the TMH 1 - financed by SANRAL and carried out under the auspices of the Materials Testing Committee (MTC) of the Road Materials Committee (RMC). q The revision of TMH 1 to SANS 3001 necessitated the use of new sieve sizes according to ISO Standards q 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 THM 1 sieves q

Defining the Issues q Continuous graded aggregate mixes not affected by implementation of new sieve sizes for grading analysis q New grading limits determined through interpolation q Example of new specifications according to SANS 3001

New Grading Spec for Asphalt

Defining the Issues q Single-sized aggregate was affected by implementation of new sieve sizes for grading analysis q New grading limits determined through interpolation, BUT § Resulted in stricter specifications in order to maintain the same grading envelope as for TMH 1 q Example of new specifications according to SANS 3001

New Grading Spec for Single Sized Aggregate

Proposed Solution q Single-sized aggregate: TMH 1 envelope to be applied for SANS 3001 sieves

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

Questions