Study of the pore structure of the lightweight concrete block with lapilli as an aggregate to predict the liquid permeability by dielectric spectroscopy

•Characterization of the pore structure of LCBL by MIP and dielectric spectroscopy.•High values of hydraulic conductivity compared to conventional concrete were found.•Prediction of porosity of LCBL by modified Bergman dielectric response equation.•New criterion for the choice of the lower frequency limit in conductivity spectra.•Prediction of the liquid permeability by a modified Katz–Thompson equation.