Experiments were carried out to clarify quantitatively the effects of spraying variables on the quality of high-strength sprayed mortar-plates. Premixed mortar mixtures with adequate proportions were used for spraying, which was made on vertical surface of molds. The quality of sprayed mortar was evaluated by comparing the flexural strength, compressive strength and density of specimens that were sawed out from the mortar. In the cases of sprayed mortar with welded wire mesh embedded in, the probability of appearance of visible pores behind the mesh was also examined.
It was shown that calculated mean pressure, which represented an approximate magnitude of vertical mean pressure acting on spraying surface, could be used as an index for evaluating the total effects of spraying variables on the quality of sprayed mortar.