What do you suggest as the safest, non-slip surface for school paving? Indentations don't really do a good job and are not attractive; exposed aggregate is rough on children's knees.
There are three possibilities: 1. As soon as the concrete has been leveled, brush it lightly with a soft broom using a circular motion. This gives an effect similar to saw marks on natural stones, and actually gives something nearer an exposed sand finish than an exposed aggregate one. 2. When the surface is level, dash handfuls of wet sand over it irregularly. This gives very slight indentation to an irregular pattern and shape. The sand should be brushed from the surface after the concrete has hardened. 3. While the concrete is still wet push a piece of black-iron gas pipe over its surface with a screeding motion while applying a slight pressure. This will give a slightly wavy non-slip surface. Polished steel bar, brass pipe or the like can also be used. The surface will then appear slightly polished, but this will not affect its non-slip properties to any appreciable extent.