Expo Line Fan has been documenting construction of the second phase of the Expo Line and recently sent along this pair of photos taken last week.
The top photo shows cement being poured on the bridge that will carry the tracks over Olympic Boulevard (foreground) and Cloverfield Boulevard (where the line of traffic is). the bottom photo was taken along the alignment at Motor Avenue.
Check out more of Expo Line Fan’s construction photos by clicking here.
I suspect that it is concrete being poured. Cement isn’t even used for sidewalks anymore.