The paper describes recent developments in the use of steel plant slags in road pavement base, sub-base and surfacing in Australia. The self cementing properties of air-cooled blast-furnace slag and the binding properties of granulated blast-furnace slag and fly-ash in `grave laitier' base and sub-base are described. A co-operative research project, which is aimed at recommending quality control tests for BOS slag, is described. Quality control testing associated with the breakdown of individual particles of steel slag is the most relevant, as it seems to have been this type of breakdown which was the principal initiator in the few failures which have been observed in laboratory specimens. Testing at elevated specimens. Testing at elevated temperatures is not recommended. Breakdown of particles can be easily observed in shallow trays under water but a break-down weight loss through a particular sieve size, as in a ten-percent fines value test, is possibly more appropriate. The length of time for this visual break-down to occur is of some importance. Depending on the particle size, particle disruption decreases to a negligible rate within 3 to 4 weeks for fresh BOS slag. Laboratory testing is at present underway to develop correlations between overseas and local test methods, with field performance. (A)
Abstract