Neapolitan Yellow Tuff as raw material for lightweight aggregates in lightweight structural concrete production

The possibility of using italian zeolitized volcanoclastites for the production of lightweight aggregates in the building industry has been tested. The paper definitely demonstrates the good attitude of the Neapolitan Yello Tuff (NYT) for the production of lightweight expanded aggregates (LEA) with bulk densities ranging between 0.9 and 1.1 g/cm3. LEA showing these features, usually manufactured with clays, are mainly used in the production of lightweight structural concrete (LSC). The physical characterization of LEAs was carried out by means of: grain size analysis, loose weight, mean density of the single grain, water absorption after 30 minutes and 24 h, and strengh of particles (UNI-7549). Afterwards, LEAs were mixed with sand, cement and water to prepare cubic concrete blocks following the UNI specifications (UNI 7549-12). On these specimens, the unit weight and uniaxial compressive strength after 28 days were determined. The investigated parameters measured both on LEAs and concretes, are comparable with those measured on materials commonly traded in Italy. The results foresee interesting potential applications for raw materials characterized by a low exploitation cost and a widespread availability on the Italian territory.