Why is there moisture on some parts of my basement slab?
The pipe could be cool and condensing humidity on the pipe (like a glass of ice water condenses moisture) . As for the moisture at the wall floor junction this is a common place for moisture to enter if there is standing water outside the foundation. We usually install a drain and gravel at the footings to prevent this and some times sumps (a pit that collects the water) with a pump to pump it out as the level rises. When I put bottom plates on concrete I use a sill seal (foam sheet to prevent the wood from sitting on the damp concrete. If this is new construction and your contract specified a dry basement you should be talking to the contractor. This is not an uncommon issue and there are measures to prevent the moisture from entering but usually excavation, draining and sealing are required. In some cases an internal sump is added to keep the water level below the slab.