Si-29 NMR and small-angle X-ray scattering studies of the effect of alkaline ions (Li+,Na+, and K+) in silico-alkaline sols. Gaboriaud, F., Nonat, A., Chaumont, D., Craievich, A. The nature of C–S–H in hardened cement pastes. Temperature effect on concrete creep modeled by microprestress-solidification theory. on Creep, Shrinkage, and Durability of Concrete and Concrete Structures (Hermes Science, London, 2005).īazant, Z., Cusatis, G. in Creep, Shrinkage, and Durability Mechanics of Concrete and Other Quasi-Brittle Materials (eds Ulm, F. Cement Chemistry 2nd edn (Thomas Telford, London, 1997).Īcker, P. Experimental Researches on the Constitution of Hydraulic Mortars (McGraw, New York, 1905). Whereas previous studies have classified water within C–S–H gel by how tightly it is bound, in this study we classify water by its location-with implications for defining the chemically active (C–S–H) surface area within cement, and for predicting concrete properties. We show that the formula, (CaO) 1.7(SiO 2)(H 2O) 1.80, and density, 2.604 Mg m −3, differ from previous values for C–S–H gel, associated with specific drying conditions.
By combining small-angle neutron and X-ray scattering data, and by exploiting the hydrogen/deuterium neutron isotope effect both in water and methanol, we determine the mean formula and mass density of the nanoscale C–S–H gel particles in hydrating cement. We also quantify a nanoscale calcium hydroxide phase that coexists with C–S–H gel. Here, for the first time without recourse to drying methods, we measure the composition and solid density of the principal binding reaction product of cement hydration, calcium–silicate–hydrate (C–S–H) gel, one of the most complex of all gels. Although Portland cement concrete is the world’s most widely used manufactured material, basic questions persist regarding its internal structure and water content, and their effect on concrete behaviour.
0 kommentar(er)
