THE ENGINEERING PROPERTIES OF GGBS/OPC GROUTS

The engineering properties of ggbs/OPC (granulated blast furnace slag/Ordinary Portland Cement) grouts have been investigated with the aim of encouraging utilization of ggbs in grouts in an application where ggbs has only found limited exploitation. Grouts with ggbs/OPC ratios in the range 3:1 to 50:1 were produced using ggbs of two fineness values. The first was 399 square metre/kg, the commercially available product, whilst the other was a 292 square metre/kg low heat alternative. These grouts were tested for compressive strength and water permeability after hydration periods of up to 365 days. Microstructural development of ggbs grouts was examined, primarily by solvent exchange and adsorption techniques, with the intention of establishing property-structure relationships. Ggbs/OPC grouts of low permeability can be produced with compressive strength values that meet the requirements of most grouting applications. Problems were encountered in the interpretation of pore structure data. Anomalous weight loss behaviour is observed during solvent exchange, indicating that the exchange process is more complex than simple counter- diffusion. Furthermore, experimental values of pore structural parameters are not unique, they have been shown to be dependent on the type of solvent used in both the exchange and adsorption process. These results and their microstructural implications are briefly reviewed. Despite the problems of pore structure characterisation, relationships between strength and microstructure are investigated. (A) For the covering abstract of the conference see IRRD 853281.