Mechanical behavior of high performance self compacting concrete at high temperatures

Radical new advancements are occurring in the cement sciences resulting ina new generation of high performance self-compacting concrete (HPSCC).HPSCC is characterized by high compressive strength and excellent durabilityproperties resulting in lighter structures and longer life. With advances in concretetechnology, HPSCC has become a new focus for researchers and the concreteindustry. Each new generation of this concrete is stronger than the previous, andthe applications of this super strong blend are endless. HPSCC is a moderncreation that is changing the way we look at construction; it is designed primarilyfor use in large construction projects (pouring rates of about 1O,000m3/day) suchas those projects began to have presence in our middle east. Since fire representsone of the most severe environmental conditions to which structures may besubjected in their life time. Furthermore, there is still a lack in the understandingthe performance of HPSCC structures in real fires due to the severe lack of dataavailable in this field. Based on this fact this research aims to study the effect ofhigh elevated temperature and direct fire on the performance of HPSCC. Thisstudy is conducted on three parts.The first part of this study is carried out to study the effect of hightemperatures on the mechanical strengths of HPSCC. Four concrete mixes wereinvestigated. The first mix represented HPSCC without fibers. The second mixrepresented HPSCC including steel fibers. The third mix represented HPSCCincluding steel and micro-polypropylene fibers. The fourth mix representedHPSCC including steel, polypropylene and polyolefin fibers. The averagecompressive strength of the investigated concrete mix was 130 MPa. Compressive,tensile and flexural strengths were measured at room temperature (RT) and afterexposure to high temperatures of 2000C, 4000C, 6000C and 7500C for 2 hours.The residual unstressed test method is followed. Microscopic examination usingScanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM).