As an active admixture, super fine steel slag powder can be mixed into concrete to produce high performance concrete. The microstructures between cement paste mixed with steel slag powder and plain cement paste are experimentally studied. The SEM of the microstructures shows that microstructure of cement paste are changed by active mineral admixture, the internal structure of the cement paste are improved. Drying shrinkage of cement mortar with different steel slag kinds and different dosage of admixtures are measured. Experiments results show the effect of steel slag powder on drying shrinkage of cement mortar.
The wheels will idle when the relative slipping speed between the wheel and rail exceeds the reference slipping speed. In order to avoid this phenomenon, the simplified model of wheel-rail traction torque transmission was established. And the adhesion coefficient and vehicle velocity are got through the disturbance observer. Then the recursive least squares method was used to forecast the slope of the adhesion-slip curve. Sliding variable structure controller was used to control the error of wheel velocity and reference velocity. From the results of simulation, this method can be effective to maintain the adhesion coefficient around the maximum. And the slipping speed approached the reference value, so the damage for wheel and rail was effectively prevented which achieved the desired effect.
Shrinkage cracking is the direct cause which leads to the deterioration of durability and integrity of concrete. In this paper, ring-test methods are used to study the early age cracking characterization of compound mineral admixtures concrete which includes steel slag, blast furnace slag and fly ash. The effect of compound admixtures on cracking characterization of concrete is discussed, restraint stress caused by concrete shrinkage and cracking age are analyzed. Through the comprehensive consideration of the free shrinkage strain, creep, restriction factors on the effect of the cracking of concrete specimens. The results show that suitable proportion mineral admixtures can be used to reduce cracking in concrete. The risk of cracking can be estimated for compound admixtures concrete, so that it will improve the durability of concrete structures.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.