The quality of cement composites after long-term contact with hydrocarbon media

الملخص EN

The paper represents the results of the study on long-term effects (up to 9 years) of hydrocarbon media-crude petroleum and mineral oil on mortars made of Portland cement and blended cements prepared of Portland cement with 30 and 70% of basic granulated blast-furnace slag and 30% of dacite tuff.

The obtained results have shown that the studied hydrocarbon media are chemically inactive against the mortar components, therefore, they do not cause any changes in their chemical and phase composition.

In accordance with this result, the studied hydrocarbon media do not have negative effects on the quality of the pore structure of mortars, and the development of their compressive strength and dynamic modulus of elasticity.

On the contrary the mortars stored in hydrocarbon media showed moderate increase of given strength characteristic — compared to the control mortars stored in water.

However, a moderate shrinkage of mortar test specimens also resulted due to the action of hydrocarbon media.

Both the strengthening and the shrinkage effects can be attributed to the surface activity of the hydrocarbon media studied.

This property seems to be very important for stability of engineering properties of concrete and for its deterioration processes.

The evaluation of hydrocarbon media as being harmless to concrete structures is valid only in the complete absence of acidic compounds, or other aggressive substances, in their composition.