Invitation to Play: Construction Site - White beans, river rocks, cornmeal and construction trucks (Dirt and Boogers)-Cool idea!
I love this idea for making mini truck tunnels to create a little construction site in your backyard. (Link goes to list of other outdoor fun ideas for kids--outdoor kitchen)
Loose parts organization. this source provides a good demonstration for how to set up loose parts
Pretend Play Invitation to Play: Small world Construction Site in a cardboard box. Toy for boys to play with sand and small cars.