Ahmed M. Al-Saleem Master Theses
Theses Title : Effect of Local Natural Pozzolanic Material on the Properties of Concrete.
The incorporation of pozzolanic material (natural and/or by-product) in concrete can significantly enhance its basic properties in both the fresh and hardened state. Natural pozzolanic material is available from basalt fields (harrat) spread within the “Edge of Arabian Shield” in the Kingdom of Saudi Arabia.
This research project was aimed at investigating the performance of concrete utilizing the natural pozzolanic material available in the kingdom. Commercial blended pozzolan cement produced in the kingdom was collected from three different sources and investigated for various engineering properties. In addition, ground natural pozzolan was incorporated in concrete at 20% as partial cement replacement to study its effect on the properties of concrete.
Local pozzolan obtained from three different locations in the Kingdom have similar chemical and physical properties and conforms to the requirements of ASTM C 618, Class N. The properties of fresh concrete did not show significant change for both commercial blended pozzolan cement concrete and pozzolanic concrete containing 20% pozzolan.
The blended pozzolan cement containing more than 12% pozzolan showed lower compressive strength compared to that of Type I cement at all ages. Whereas blended cement containing about 5% pozzolan demonstrated similar compressive strength as compared to Type I cement. These results suggest that local natural pozzolan ground to fineness similar to cement are not fully activated. Several activation methods can be used to activate the pozzolanic reaction. The activation by calcination did not show any benefit. However, activation by elevated temperature curing showed promising results for the increase in the strength development. Other activation methods should be investigated such as mechanical activation (prolonged grinding) and chemical activation.