https://fronterasdesk.org/sites/default/files/field/docs/2016/07/Bernstein- The Trump Wall.pdf
Based on Trump's statements about the dimensions of the Wall, and our own assumptions, we have estimated the quantities of concrete (and cement) required to complete construction. Based on our research, our base case for the Wall is a length of 1000 miles, at 40ft high (with an additional 7ft below ground, sufficient to deter rudimentary tunnelling) and a thickness of 10 inches. We also assume that a 5ft wide and 1ft deep concrete strip foundation is required along the entire length. Based on these parameters, The Trump Wall would require a total of 7.1 million m3 of concrete at a cost of over $700m at current prices. Assuming a standard cement content, this volume of concrete would require around 2.4 million tonnes of cement at a cost of around $240m. Concrete costs would therefore account for about 5% of a total project cost of $15bn, which includes 2% of total cost for cement. Since there is some disagreement about the necessary height of the wall, we present a sensitivity of our calculation at various heights in Exhibit 6.
If the wall was 30 feet high and out of concrete..........this older estimate of the Concrete cost alone would be 586 Million for the concrete......doesn't count the rebar, forms and labor required...........but that is a estimate of the volume of concrete to build the wall across the Southern Border.
So the Military would need 14.1 million tonnes of concrete for a concrete wall..........Labor is free.........rebar would have to be figures and concrete forms.
Note.........this article is against the wall..............but did some good calculations on the materials needed..............