ABSTRACT
The purpose of this article is to illustrate the experience gained in the field of wet-sprayed concrete in the execution of tunnel construction work for high-speed railway lines in Italy, with particular regard to the influence exerted by the nature and dosage of accelerating admixtures on compressive strength over short and long curing periods. This paper therefore illustrates the results obtained from the comparison between mixtures of sprayed concrete made with silicate and with alkali-free accelerating admixtures, in terms of compressive strength, observed at time intervals of 2 and 28 days
