1 Calcium Silicate Hydrates in cementitious materials 1.1 Sustainability Challenge .... ..................... 1.2 Cement Chemistry Notation A Primer ............ 1.3 Hydration of Portland Cement ...................... 1.3.1 Initial and slow reaction periods . . . . . . . . . . . . . 1.3.2 Nucleation & Growth of C-S-H . . . . . . . . . . . . . 1.3.3 Open Questions in Cement Hydration . . . . . ....

Cracking is one of the most severe problems facing the concrete industry worldwide. Of critical importance is the drastic decline of durability associated with these cracks, and the resulting cost of repair or replacement of concrete structures. This research examines the effect of crack width and crack frequency upon the durability of reinforced mortar, quantified by water permeability. Crack ...

Cement-based concrete is the most widely used building and construction material in the world. Although concrete itself is relatively durable when used under the mild environments, its intrinsic weak tensile strength greatly limits its application due to its porous structure. Traditional strategies to overcome this weakness of concrete include utilization of various reinforcing materials, such ...

In this paper, the sorption isotherm and the hygral deformation of a tensile strain-hardening fiber reinforced engineered cementitious composite (ECC) is described using a physical model. The influence of using a low alkali content Portland cement on the physical mechanisms of drying shrinkage is discussed. From a durability point of view the crack width of a material as a result of restrained ...

The paper proposes a combined application of composite theory and Powers’ model for microstructural development for the estimation of the diffusion coefficient as a function of the moisture content of a defect-free cementitious material. Measurements of chloride diffusion in mortar samples (440 kg/m rapid-hardening Portland cement, w/c = 0.5, maturity minimum 6 months) stored at 65% and 85% RH,...

This paper describes analytical methods that can be used to determine the deflections and stresses in highly compliant graphite-reinforced cementitious composites. It is demonstrated that the standard transform section method fails to provide accurate results when the elastic modulus ratio exceeds 20. So an alternate approach is formulated by using the rule of mixtures to determine a set of eff...

This article describes an improvement on a previous model proposed by Ba~ant and Najjar, in which moisture diffusivity and moisture capacity are treated as separate parameters. These parameters are evaluated from independent test results, and are shown to depend on the water:cement ratio, curing time, temperature, and cement type. The moisture capacity is obtained as the slope of the adsorption...

Degradation of the cementitious bond between steel rebar and concrete and that between old and new mortar under cyclic shear loading was observed nondestructively by measuring the contact electrical resistance of the joint. Degradation, which caused a decrease in bond strength but no visual damage, was indicated by an abrupt increase in the resistance at a small fraction of the fatigue life. Bo...