کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1456794 | 989224 | 2012 | 13 صفحه PDF | دانلود رایگان |
This contribution aims at (1) determining experimentally the first desorption isotherms of two high performance concretes (based on CEM I and CEM V cements), at three different temperature levels T = 20, 50 and 80 °C, and (2) showing whether these may be simply described by adsorption and capillarity.Results at 20 °C compare well with recently published results; in particular, an important desorption is observed at high RH (≥ 98%). A simple pore network model, based on Kelvin–Laplace's capillary theory, is implemented, and shows the existence of two main de-saturation modes, one at high pore radii (capillary pores), the other for pore radii on the order of a few nanometers (C-S-H porosity), where desorption is shown to occur. A complementary drying mechanism is evidenced at 80 °C, which is attributed to ettringite and/or C-S-H degradation. Finally, proper numerical fitting of all isotherm data is achieved using the well-known three-parameter BSB model.
Journal: Cement and Concrete Research - Volume 42, Issue 2, February 2012, Pages 384–396