The ASTM C150 standard specification for Portland cement now permits the cement to contain up to 5% of ground limestone. While these and much higher levels of limestone filler substitution have been employed in Europe and elsewhere for many years, changing the ASTM standard has been a slow process. Having computational tools to assist in better understanding the influence of limestone additions...

Exposure conditions significantly affect the resistance of cement to sulfate attack. This article investigates the effect of sulfate on electrical conductivity of ordinary Portland cement (OPC). Cement paste specimens were prepared according to water/cement (W/C) ratio equal 0.25 either free of sodium sulfate or its addition with concentrations of 5000ppm, 10000ppm and 15000ppm by weight. This ...

The moisture and drying resistance of a novel cement based nanocomposite, polymer intercalated/exfoliated (PIE) cement, is analyzed. The effects of the post-processing treatment procedure and the nanofiller content are discussed. The experimental results indicate that the flexure strength of the PIE cement is higher than that of ordinary Portland cements by more than an order of magnitude, and ...

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 . . . . . ....

To improve the corrosion protection provided to prestressing strands, anti-bleed grouts are used to fill voids in post-tensioning ducts that result from bleeding and shrinkage of older portland cement grouts. Environmental differences caused by exposing the strands to dissimilar grouts, however, have the potential to cause rapid corrosion. Portland cement grout, gypsum grout, and four commercia...

AIM To compare the ability of Portland cement and mineral trioxide aggregate (MTA) to prevent coronal leakage through repaired furcal perforations in molar teeth. METHODOLOGY The pulp chambers of 36 human mandibular molar teeth were accessed and the root canal orifices were located. The roots were horizontally sectioned in the middle third. Composite resin was used to fill the root canal orif...

In this research the effects of adding silica and alumina nanoparticles on flow ability and compressive strength of cementitious composites based on Portland cement were investigated. In the first stage, the rheological behavior of different samples containing nanosilica, nanoalumina and polypropylene, polyvinyl alcohol and polyethylene fibers were evaluated. With increasing of nanoparticles in...