Structural, radically curable resin compositions suitable for (re)lining contain: a. 30-70 wt. % of a resin characterized by (i) a molecular weight Mn between 500 and 3000 and (ii) an acid value between 0 and 30 mg KOH/g resin, and wherein at least 80% of the total amount of resin is vinyl ester resin, b. 30-70 wt. % of at least one reactive diluent, characterized in that at least 25% of the reactive diluent is a difunctional diluent having a molecular weight Mn between 200 and 500 and the optional monofunctional diluent having a molecular weight Mn between 100 and 200, c. 0.00001-5 wt. % initiator, d. 0.00001-5 wt. % inhibitor. wherein the average molecular weight per reactive unsaturation (WPU) of the components (a) and (b) is equal or greater than 190 Dalton and that the amount of styrene in the resin composition is less than 5 wt. % (calculated as wt. % of the total weight of the components (a), (b), (c) and (d)).