New generation of fiber self-compacting concrete based on pyrophyllite

The aim of this work is to develop new-generation ultra-high-performance fiber self-compacting concretes (SCCs) by introducing pyrophyllite rock powder as a cement substitute and assess its effects on the fresh and hardened properties. Three series of concretes were developed. The first series of reference fiber SCCs without pyrophyllite contained 1% adherent steel fibers or 1% slippery polymeric polypropylene fibers or a mixture of 0.5% steel and 0.5% polypropylene fibers. The second and the third series contained fibers and 10 or 20% pyrophyllite. The results showed that incorporation of pyrophyllite generates good fluidity, satisfactory stability without any risk of segregation and an ability to flow in a confined environment without risk of blocking of the fiber SCC. Moreover, the ultrasonic velocity, elastic dynamic modulus and rebound hammer number increase with increasing pyrophyllite rate. Also, a gain in compressive and flexural strengths was obtained at 28 days and the fiber SCCs were judged to be of good quality. The best formulation is the one containing steel fibers and 10% pyrophyllite. This additive has shown its potential to be used as a substitute for cement and its beneficial effect in protecting the environment.