Mechanical properties and durability of alkali-activated fly ash-municipal sludge concrete

In this study, modified municipal sludge was used in place of fine aggregate to manufacture concrete, and it's revealed how different quicklime and sludge contents affect concrete. The best modified sludge concrete group was used for the performance improvement test, after which the constitutive model, the carbonation depth prediction model, and the freeze -thaw damage model were fitted. The results showed that the compressive strength of the L10S10 was best in experiment of modified municipal sludge concrete. Under alkali activation, fly ash absorbed the remaining alkali in modified municipal sludge, promoted concrete hydration, and improved the mechanical characteristics of concrete. The F10N4 group had the best activation effect, with a compressive strength of 50.61 MPa. Test results could be accurately reflected by the constitutive model and carbonation depth prediction model that were devised. The freeze -thaw damage model based on relative dynamic elastic modulus has a correlation coefficient greater than 0.98.