Shehab Mourad

Optimized Fresh and Hardened Properties of Strain Hardening Cementitious Composites: Effect of Mineral Admixtures, Cementitious Composition, Size, and Type of Aggregates

AbstractThe present paper thoroughly investigates the effects of mix design with various water-to-binder (W/B) ratios, types of mineral admixture and types and sizes of local sands on the tensile d...

Flexural Behavior of Beams Reinforced with Steel Bars Exceeding the Nominal Yield Strength

If steel manufactures usually comply with the minimum code specifications, the nominal yield strength of rebar can however be significantly exceeded in many countries, depending on the steel manufacturing processes. Such an increase in yield strength can have negative effects on the flexural behavior of beams designed as tension controlled, and reduce their ductility, an essential property in seismic resisting structures. An experimental and analytical study of the flexural behavior of reinforced concrete (RC) beams was conducted through the investigation of the Moment-Curvature relationships and the ultimate steel strains. The main variable was the level of the actual steel yield stress as compared to the nominal value. It was found that unexpectedly high values of steel yield stress reduce the beam ductility and violate the tension-control condition which was enforced in the design stage. Appropriate design corrections are proposed to account for high yield stress values in order to achieve the desired ductility of beams while maintaining the moment capacities.

Optimized Fresh and Hardened Properties of Strain-Hardening Cementitious Composites: Effect of Sand Size and Workability

AbstractThe feasibility of the preparation of strain-hardening cementitious composites (SHCC) relies to a great extent on the properties of one of its main constituents, quartz sand. The particle size distribution (PSD) of such sand should satisfy certain criteria specifically for SHCC to deliver quasi-static responses under tensile stress. The successful use of naturally available sand helps preparation of a cost-effective SHCC. The aim of the current paper was to evaluate the potential use of white quartz sand that is naturally available in the Arabian Gulf with different PSDs to produce different mixtures of SHCC. These mixtures were prepared with different ranges of workability to obtain optimized fresh and hardened properties with improved strain-hardening response. The effect of workability on the compressive, flexural and tensile properties has shown that there is an optimal workability range among the defined ranges that provided improved strain-hardening responses under tensile stress. The mode o...