The porous aggregate pre-soaking in relation to the freeze–thaw resistance of lightweight aggregate concrete

The results of an investigation into the influence of porous aggregate pre-soaking on the freeze–thaw resistance of lightweight concrete are presented. Three concrete mixtures were prepared, differing in the degree of porous aggregate saturation: LC1 (oven dried aggregate), LC2 (aggregate with a moisture of 13%) and LC3 (30% pre-soaked aggregate). The basic physico-mechanical and fracture characteristics of the manufactured concrete at the ages of 28 and 90 days were also determined. Non-destructive methods were used for the determination of specimen degradation after every 25 cycles. The experiments were completed via the carrying out of destructive tests in order to determine the static modulus of elasticity, fracture and strength parameters. Experiments showed that non-destructive methods are insufficient for the description of the total rate of damage to internal structure. The fracture and strength tests appeared to be more sensitive to micro-cracks identification. Also the tests of re-saturation helped to identify damages of the lightweight concrete structure. Obtained results showed that the concrete prepared from the oven dried aggregate is most resistant to the cyclical freezing and thawing.

► We studied the freeze–thaw resistance of lightweight concrete with different degree of porous aggregate saturation.
► We examined the changes in the physico-mechanical and fracture characteristics.
► Non-destructive methods appear to be insufficient for the description of the total rate of damage to internal structure.
► The fracture and strength tests are more sensitive to micro-cracks identification.
► The tests of re-saturation identified damages of the lightweight concrete structure.