A mortar composition in the form of a dry powder, ready for use, comprising at least one powdery binder and at least one aggregate, as well as possibly at least one standard additive and/or adjuvant, and formed from particles, at least some of which, referred to as fine particles, are liable to produce an emission of dust, characterized in that it also comprises a fluid additive that consists of least one non-polar hydrocarbon organic substance and that has a capacity for agglomeration of the said fine particles, and in that the dry mortar composition comprises agglomerates of fine particles formed by the fluid additive.