In vitro antagonism of Rhizobium strains isolated from various legumes

This paper presents theoretical and applied information in the field of alkali-aggregate reactivity (aar) in concrete. the aspects discussed include basic concepts of the reaction and expansion mechanisms,conditions conducive to the development and the sustainability of aar in concrete,field and laboratory investigation programs for evaluating the potential alkali-reactivity of concrete aggregates,selection of preventive measures against aar,and the management of structures affected by aar. lithium nitrate inhibitor in the form of liquid solution was used in the concrete mix as an admixture to prevent asr. this substance will react with silica gel and produces a non-expansive material when absorbing water to prevent cracking. in addition lithium inhibitor,ground granulated furnace slag,a well-known cement substitution pozolan was used in the specimens as a less expensive material. silica fume as a cement replacement material was also used to observe its asr inhibiting effect. slag and silica fume have a lower alkali content in comparison to ordinary portland cement and can reduces the rate of asr. in this study effective recommendations to produce durable concrete resistant to asr are proposed for the new concrete structures.