COULINEX, based on NHL 3.5, is a grout, which can be used for injection. It has no cement or pozzolanic additions and can be used on its own or with the addition of sand, depending on the size of the voids. COULINEX can be applied by gravity feed or by pump with a very low pressure. In fine injection work it can be applied on its own or with very fine aggregate, depending on the voids size.