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Effect of first drying upon the pore structure of hydrated alite paste
AbstractWater losses and gains, nitrogen adsorption, and imbibition of organic fluids were measured in a study of the pore structure of two, well-hydrated alite pastes that had original water/alite ratios of 0.4 and 0.6 by weight. Drying from saturation to a relative humidity in the range 0.3 to 0.8 was a particularly slow process probably because some pores emptied via smaller pores. The nitrogen adsorption measurements, on pastes in which the water has been removed by organic fluid replacement, suggested that micropores were closing as a result of capillary tensions developed at relative humidities between 0.7 and 0.4. The loss of surface area was recoverable with resaturation of the pastes with water. Imbibition of water and organic fluids indicated that there was an irrecoverable pore volume loss after drying and rewetting that was dependent upon the relative humidity of drying.
ZusammenfassungAfgivelse og optagelse af vand, nitrogen adsorbtion og optagelse af organiske vaesker blev målt ved en undersøgelse af porestrukturen på to vel hydratiserede “alite pastes” med vaegtforhold vand/alite på 0,4 og 0,6. Udtørring fra den fuldtmaettede tilstand til et relativt fugtighedsområde på 0,3 til 0,8 var saerlig langsom, sandsynligvis fordi nogle af porerne udtørrede gennem mindre porer. Nitrogen adsorbtiosmållinger på prøver, hvor vandet var udskildt og erstattet ved hjaelp af organiske vaesker viste tegn på, at mikroporer lukkede sig på grund af kapillar kraefter, som dannedes i det relative fugtighedsområde 0,7 til 0,4. Tabet af nitrogen overfladeareal kunne gevnindes ved vandmaetning af prøverne. Optagelse af vand og organiske vaesker viste, at udtørring og genmaetning resulterede i et porevolumen tab afhaengig af udtørringsgraden.
Effect of first drying upon the pore structure of hydrated alite paste
AbstractWater losses and gains, nitrogen adsorption, and imbibition of organic fluids were measured in a study of the pore structure of two, well-hydrated alite pastes that had original water/alite ratios of 0.4 and 0.6 by weight. Drying from saturation to a relative humidity in the range 0.3 to 0.8 was a particularly slow process probably because some pores emptied via smaller pores. The nitrogen adsorption measurements, on pastes in which the water has been removed by organic fluid replacement, suggested that micropores were closing as a result of capillary tensions developed at relative humidities between 0.7 and 0.4. The loss of surface area was recoverable with resaturation of the pastes with water. Imbibition of water and organic fluids indicated that there was an irrecoverable pore volume loss after drying and rewetting that was dependent upon the relative humidity of drying.
ZusammenfassungAfgivelse og optagelse af vand, nitrogen adsorbtion og optagelse af organiske vaesker blev målt ved en undersøgelse af porestrukturen på to vel hydratiserede “alite pastes” med vaegtforhold vand/alite på 0,4 og 0,6. Udtørring fra den fuldtmaettede tilstand til et relativt fugtighedsområde på 0,3 til 0,8 var saerlig langsom, sandsynligvis fordi nogle af porerne udtørrede gennem mindre porer. Nitrogen adsorbtiosmållinger på prøver, hvor vandet var udskildt og erstattet ved hjaelp af organiske vaesker viste tegn på, at mikroporer lukkede sig på grund af kapillar kraefter, som dannedes i det relative fugtighedsområde 0,7 til 0,4. Tabet af nitrogen overfladeareal kunne gevnindes ved vandmaetning af prøverne. Optagelse af vand og organiske vaesker viste, at udtørring og genmaetning resulterede i et porevolumen tab afhaengig af udtørringsgraden.
Effect of first drying upon the pore structure of hydrated alite paste
Parrott, L.J. (author) / Hansen, W. (author) / Berger, R.L. (author)
Cement and Concrete Research ; 10 ; 647-655
1980-06-25
9 pages
Article (Journal)
Electronic Resource
English
Effect of age on diffusion in hydrated alite cement
| Tema Archive | 1984
Effect of age on diffusion in hydrated alite cement
| Tema Archive | 1984