Frost-salt Testing Non-air Entrained High-Performance Fly-ash Concrete. Part I: Relations Liquid uptake - Internal Cracking – Scaling

The surface scaling of low CO₂-emission High Performance Concretes (HPC) was studied in freeze/thaw performance tests with a 3 mm layer of 3% NaCl on the surface to investigate whether such concretes can be made frost durable without air entrainment. Four different non-air entrained silica fume (SF)-fly ash concrete mixes with w/b = 0.30 – 0.35 with 91d strengths >100 MPa were investigated after 3 different curing conditions (Normal, Dried, Wrapped). The w/b=0.30 CEM IIA reference mix without additional FA had lowest scaling following all curing conditions. However, all 4 mixes at all 3 curing conditions had severe internal damage. Liquid Uptake (LU) during freeze/thaw related best to internal damage. The correlation between LU-scaling and strain-scaling was very good for wrapped curing which also showed high internal damage. We therefore suggest proceeding in modelling simultaneous salt scaling and internal damage.