39 research outputs found
A reaction-diffusion model for the hydration/setting of cement
We propose a heterogeneous reaction-diffusion model for the hydration and
setting of cement. The model is based on diffusional ion transport and on
cement specific chemical dissolution/precipitation reactions under spatial
heterogeneous solid/liquid conditions. We simulate the spatial and temporal
evolution of precipitated micro structures starting from initial random
configurations of anhydrous cement particles. Though the simulations have been
performed for two dimensional systems, we are able to reproduce qualitatively
basic features of the cement hydration problem. The proposed model is also
applicable to general water/mineral systems.Comment: REVTeX (12 pages), 4 postscript figures, tarred, gzipped, uuencoded
using `uufiles', coming with separate file(s). Figure 1 consists of 6 color
plates; if you have no color printer try to send it to a black&white
postscript-plotte
The Effect of Using Saturated Lightweight Aggregate on Shrinkage and Hydration Degree of High Performance Concrete
Preliminary observations of water movement in cement pastes during curing using X-ray absorption
High Performance Structural Lightweight Concrete and Internal Curing and Enhanced Hydration
Measurement of Water Transport from saturated pumice aggregates to hardening cement paste
Effects of High Temperature on the Residual Performance of Portland Cement Concretes
In this work we analyzed the "residual" performance of Portland cement concretes heat-treated at 600 °C after cooling down to room temperature. Concretes with characteristic compressive strength at 28 days of 45 MPa and of 60 MPa were studied. The heat-treatment was carried out without any imposed load. We measured the residual compressive strength and modulus of elasticity. The geometry of the structure was described by mercury intrusion porosimetry and nitrogen sorption tests. We observed a decrease of residual compressive strength and modulus of elasticity, with the raise of heat-treatment temperature, as a result of heat-induced material degradation. The results also indicated that the microstructural damage increased steadily with increasing temperature. Based on the results of this experimental work we concluded that residual mechanical properties of concrete are dependent of their original non heat-treated values