Estimated and real durability of unfired clay bricks: Determining factorsand representativeness of the laboratory tests

Abstract

This paper presents an analysis of the representativeness of the main laboratory tests and the real dura-bility of earth-based construction materials. For this study, a natural marl soil, mixed with different per-centages of silica sand, was treated with portland cement, hydraulic lime, a mix of lime and groundgranulated blastfurnace slag and other binder composed of a high magnesium oxide waste mixed withground granulated blastfurnace slag. All the combinations were characterized based on the usual dura-bility related laboratory tests as are: maximum density, unconfined compressive strength, wetting anddrying, Swinburne accelerated erosion resistance, capillarity water absorption, total water absorptionand freeze/thawing cycles. The results of these tests have been related to the real durability of the sam-ples for eighteen months of outdoor exposure. They revealed the positive effect of sand adding in thematerials durability and the great result of the binder based on magnesium oxide with ground granulatedblastfurnace slag. It was also demonstrated the representativeness of the water absorption test as a dura-bility indicator of earth based construction materials durability.