Experimental investigation on annual changes in mechanical properties of structural concretes with various types of lightweight aggregates

This study presents the compiled experimental data of compressive strength and the modulus of elasticity for five different lightweight concretes cured up to 365 days and compares them with those for a normalweight concrete. Mechanical properties sharply increased during early stage approaching asymptotic values, depending on design strength codes. Various empirical relationships approximately represent the experimental data, with the different types of concrete exhibiting discrepancies within acceptable bounds. Results highlight that the time-dependent mechanical properties of concretes containing lightweight aggregates can be reasonably estimated using conventional empirical models, provided that values at 28 days of curing are accurately known. Relationship between measured strength and modulus provides the first approximations, corroborated by coinciding values from nondestructive testing. The evolution of density and the effect of curing conditions are also discussed. These experimental results demonstrate that the type of lightweight aggregate strongly influences the mechanical properties of concretes.