09-06-2010, 02:28 AM
Fishboy,
Concrete shrinks when it cures. period. Rebar and remesh will keep it from seperating very far and it is is good that you included them, but you will still get some cracks. Maybe not for a month or 4, but by it's nature, it has to shrink, therefore crack.
On a 4" concrete slab, for instance, rule of thumb is a control joint every 8'. On a narrow walkway, as you describe, more often, there is a formula, but I forget the exact calculations. Ever notice on sidewalks the perpendicular joints that are trowled in? Those are control joints. They will help control where the cracks will be. It is just the nature of the beast.
I knew a concrete contractor who's contracts read "This concrete is quaranteed to crack".
Dan
Concrete shrinks when it cures. period. Rebar and remesh will keep it from seperating very far and it is is good that you included them, but you will still get some cracks. Maybe not for a month or 4, but by it's nature, it has to shrink, therefore crack.
On a 4" concrete slab, for instance, rule of thumb is a control joint every 8'. On a narrow walkway, as you describe, more often, there is a formula, but I forget the exact calculations. Ever notice on sidewalks the perpendicular joints that are trowled in? Those are control joints. They will help control where the cracks will be. It is just the nature of the beast.
I knew a concrete contractor who's contracts read "This concrete is quaranteed to crack".
Dan