BRE IP17/05 PDF

Introduction

This Information Paper provides guidance on the design of low-strength concrete mixes for use in firm female secant piles. It complements BRE Special Digest SD1 (SD1:2005) [1] which does not include mixes containing more than 80% of ground granulated blastfurnace slag (ggbs) used in specialist applications such as secant piling. The concrete for the female piles must be strong enough not to be damaged during the boring of adjacent male piles, but not so strong that it cannot be bored without deviation. It must also have sufficient resistance to sulfates and other aggressive chemicals in the ground to provide durability for the required working life.

Concretes with very high levels (>80%) of ggbs have been used successfully in constructing female secant piles, offering mixes with the appropriate early-age properties to allow the piling operations to be carried out. Because SD1:2005 does not cover mixes containing more than 80% of ggbs, this Information Paper builds on existing laboratory and field data to provide guidance on suitable mixes for concrete containing between 81 and 95% ggbs used in different chemical environments.