In the presentation of a Renault FT17 tank model, I mentioned the use of concrete roadblocks interlocked by metal wire and or chains as a primitive defensise against tanks.
see http://www.landships.net/t61670046/135-rpm-renault-r17-aef-tank-with-tanksperre/
Recently I found in the AEF Official History of the 304th Engineers 79th Division WW1, which can be found and downloaded on http://www.314th.org/books/304th-engineers.html ,some references to the use of this defensive system and a few photographs.
The book is a very interesting read, also dealing with repairing and cleaning the old battlefields
