DRYING SHRINKAGE OF READY-MIXED HIGH-PERFORMANCE CONCRETE

The paper reports on drying shrinkage undergone by ready-mixed high pe rformance concrete (HPC). Shrinkage measurements were carried out on c oncrete specimens as well as on instrumented reference columns Two dif ferent HPC were tested. The first one had a compressive strength of 98 MPa (14.200 psi) at 91 days and the second had a compressive strength of 80 MPa (11,600 psi). The first contained silica-fume but the secon d did not. The effects of the following factors were investigated: cur ing tune curing conditions, silica fume content, and water-cementitiou s materials ratio. It was found that the longer the curing time the lo wer the dying shrinkage, and that the lower the water-cementitious mat erials ratio the lower the drying shrinkage. Drying shrinkage of small specimens was compared to that of actual large-sized columns made wit h these HPC Shrinkage measured by a conventional laboratory test was f ound to overestimate shrinkage of HPC in a real structure. The validit y of using an ACI 209 expression derived for ordinary concrete to Pred ict drying shrinkage of HPC was also investigated. It was found that t his expression can be used for high-performance concrete only if new p arameter values are considered