<p>This Architectural Drawing is AutoCAD 2d drawing of Lean concrete Sectional working drawing. Lean concrete is <strong>used under the foundations</strong>. It is good for providing a flat bottom in uneven or dirt terrain. Lean concrete has a lower level of cement in it, which is why it's mostly used for fillings or under the foundations, to keep it protected from the soil. A lean mixture is <strong>a fuel/air mixture containing a relatively low proportion of fuel</strong>. A lean mixture can be caused by too little fuel or too much air. Too much oxygen indicates a lean mixture and the need for less fuel. For more details and information download the drawing file.</p>