tape for foam and sealant for plastic sheeting

I am use the Tyvek tape to seal the foam board joints. But the tape seams not strong. It was recommended by the staff in Lowes. Is it the right tape?

Anybody knows is there any sealant can be used to glue 6mil poly (plastic sheeting) with concrete?

And I also need glue to seal the joint (overlap) of two poly.

What is not strong, the tape's adhesive or the tape itself? Around here we use Tuck brand tape. To seal between layers of poly, we use acoustical sealant.
http://www.cttgroup.com/cantech/en/details/135/
http://www.tremcosealants.com/commercial/products/product_detail.asp?id=32

here is the best answer I found: http://www.diychatroom.com/f103/best-tape-sealant-6-mil-plastic-sheeting-crawl-space-102593/