الفهرس 
AbstractOnly 14 pages are availabe for public view
 |  | from | 252 |  |  |
| | | from | 252 | | |
Abstract
The effect of acid/seawater solutions at elevated temperatures on good quality concrete has been investigated for industrial applications as well as sewers, oil storage facilities, artificial lakes and other concrete structures subjected to acid attack and bacterial activity. A comprehensive research prcgramte was undertaken at Imperial College which considered various parameters such as concrete type (using 100% OPC or slag), pre—conditioning (at 100% RH or in
seawater), acid type (acetic and sulphuric), PH level (8, 5, and
3) and temperature level (20, 40 and 60°C). The effects of these parameters on the durability and behaviour of the concrete has been examined mechanically, cheimoally and microstructurally. Mechanical analysis tests included capressive strength measurements, weight loss analysis, mortar bar strain tests and depth of attack studies. Chanical and micro—structural analysis included electron probe micro—analysis, elerient distribution, x—ray diffraction analysis, liquid chromatography and scanning electron microscopy.
The most significant results relate to the formation of the multi—layer system of reaction prcxiucts, containing significant ajnounts of gypsum, on the surface of the cement paste specim2ras which tended to retard the rate of acid attack. The effect of t&nperature level was reduced because of this layer. Reffoval of the layer during exposure results in a nore pronounced temperature effect. The pre—conditioning regime did not generally influence the results. The pH level was a very significant factor in most of the tests. Acetic acid was xivre aggressive than sulphuric acid for the same pH level and under the same environmental conditions. Concrete containing 65% repiacen’ent of ordinary Portland cewent (OPC) with slag generally gave improved results for temperatures of 20°C and 40°C but at 60°C its ccfnpressive strength was not significantly higher than a similar concrete cvntaining 100% OPO.