Comparative study of the normal and high strength pozzolanic concrete on the strength and durability at elevated temperature

Abstract EN

Cement based materials play an important role in the design and performance of future deep radioactive waste disposals and used as a solidification matrix and / or as backfill and construction material for determine the aqueous chemistry of low–and intermediate level radioactive waste for very long periods of time.

The strength and durability performance of normal- and high-strength pozzolanic cement concretes incorporating silica fume, fly ash, and blast furnace slag was compared at elevated temperatures up to 800°C.

The strength was studied and determined by using different scenarios, including the case, an unstressed residual compressive strength test, while durability cement was investigated by rapid chloride diffusion test, and crack pattern observations.

It was found that pozzolanic cement concretes containing fly ash and blast furnace slag give the best performance particularly at temperatures below 600°C as compared to ordinary Portland cement concretes.

Explosive spalling occurred in most high-strength concretes (HSCs) containing silica fume.

A distributed network of fine cracks was observed in all fly ash and blast furnace slag concretes, but no spalling or splitting occurred.

The high-strength pozzolanic concretes showed a severe loss in permeability-related durability than the compressive strength loss.

Thirty percent replacement of cement by fly ash in HSC and 40 wt% replacement of cement by blast furnace slag in normal strength concrete (NSC) was found to be optimal to retain maximum strength and durability after high temperatures