To make a sink, washbasin or basin in cement or waxed concrete, you obviously need to choose the right material.
Cement or concrete must be particularly resistant to its own weight, to impact, to moisture and to greasy stains caused by cosmetics.
This is why Marius Aurenti recommends using high-performance fiber-reinforced concrete – a mortar into which fibers have been added to increase the strength of a block – and covering it with a varnish.