391
4000.051
Bamforth, P.B., et al.
Concrete
Collection
The Concrete Society, London
1987
April, Vol. 21, No. 4
7-18
Y
“Until recently the words concrete – man-made rock – and durability were virtually synonymous. Now the question is being asked why Roman concrete was more durable than some of the present-day mixes.It should be pointed out, for the sake of accuracy, that it is `Roman lightweight concrete’ and not just `Roman concrete’ which lasts millennia.
Fortunately Lytag shares not only but two features with this excellent structural medium of antiquity. Firstly it is lightweight and secondly it is made from fly ash – man-made pozzolan – and consequently contributes to making more durable concrete than natural gravel or crushed stone.
It is thus amazing that even the latest Code of Practice discriminates against lightweight aggregate concrete when durability requirements are pre-eminent. In my opinion the design of structures under severe exposure to elements should require to get waivers if lightweight aggregate concrete in general and Lytag aggregates in particular is not proposed for this purpose.
I trust that the excellent papers presented at the symposium and especially those which dealt with permeability do more than justify my statements.”
This set of articles includes references to both sintered fly asn and rotary kiln expanded shale, clay, and slate.