Title: A Study on Delayed Deformations of an Ultra High Strength Cementitious Material

Author(s): A. Loukili, P. Richard and J. Lamirault

Publication: Symposium Paper

Volume: 179

Issue:

Appears on pages(s): 929-950

Keywords: compressive strength; creep; pozzolans; shrinkage; thermogravimetry

DOI: 10.14359/6080

Date: 6/1/1998

Abstract:
This paper presents the results of an experimental investigation of RPC (Reactive Powder Concrete) on shrinkage and creep under uniaxial compressive loading. The RPC are ultra-high strength concretes characterized’ by high silica fume content and steel fibers reinforcement. The present study focuses on RPC with a very low water/binder (0.17) ratio and a compressive strength at 28 days of 160 and 200 MPa after a 90°C heat-treatment. The thermogravimetric analysis shows that in RPC a high proportion of cement remains unhydrated, and the pozzolanic reaction becomes predominant two weeks after mixing. The autogenous shrinkage and creep of RPC were measured on sealed specimens. The stress level on the creep specimens represented 20 % of the concrete compressive strength at the time of loading. The basic creep kinetics of RPC is very rapid and does not differ from high strength concrete, whereas its magnitude can be twice as much. The basic creep amplitude and kinetics of RPC are strongly affected by the age of loading. After a heat-treatment of RPC at 9OC, the shrinkage becomes insignificant, and the basic creep is highly reduced.