Consideration is given to the practical implications of the research. Concretes containing BS EN 450 PFA, which offers scope for a greater utilisation of PFA, designed to satisfy the requirements of BS 5328 will have similar durability to concretes currently permitted. Studies of concrete durability, comprising (i) chloride diffusion, (ii) carbonation, (iii) alkali–silica reaction, (iv) sulfate resistance, (v) freeze–thaw resistance and (vi) abrasion resistance, show that providing compensation for PFA fineness on strength is made (equal strength concretes), then similar durability performance between concretes containing PFA of different fineness is achievable, within the limits set in both BS 3892: Part 1 (12% retained) currently referred to in BS 5328 and BS EN 450 (up to 40%) which is referred to in the forthcoming BS EN 206 which is expected to replace BS 5328 in 1999. A method for taking account of strength reductions due to PFA fineness is proposed, which involves simple adjustment to the water/binder ratio, via the water content, binder content, or both.
The loss-on-ignition (LOI) of PFA up to 8.0% was found to have a negligible effect. bearing stress) U1.5 A more detailed method for the assessment of ¾m is given in Section 2 of BS 8110-2:1985. The results of strength development tests show that PFA fineness has an influence on strength, with a gradual reduction with decreasing fineness, as percentage retained on a 45-μm sieve. Table 2.2 Values of ¾m for the ultimate limit state Reinforcement (prestressing steel included) 1.05 Concrete in flexure or axial load 1.50 Shear strength without shear reinforcement 1.25 Bond strength 1.4 Others (e.g. BS 8500 (2006), Part 2: Specifications for constituent materials and. In particular, strength development and the durability of concrete that follows the guidance in BS 5328: Part 1: 1991, were studied. BS 5328-1 (1997), Concrete: guide to specifying concrete.
This paper describes a study carried out on the use of PFA to BS EN 450: 1995 as a binder component in concrete.
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