Drying shrinkage of geopolymeric recycled aggregate concrete

In this work, the drying shrinkage behavior of geopolymeric recycled aggregate concrete (GRAC) was studied with attention devoted to the mass loss, drying shrinkage strain, and sensitivity of drying shrinkage to water loss. The GRACs were prepared based on different fly ash/slag ratios and various dosages of recycled aggregate. Also, two types of curing regimes were employed, including ambient and heat curing. Additionally, the drying shrinkage strain development of GRACs was fast in the first 28 days and then slowed down with time. Recycled aggregate dosage increased the dry shrinkage strain while increasing the slag content and curing temperature reduced the drying shrinkage strain. Analogously, the sensitivity of drying shrinkage to the mass loss was raised under high recycled aggregate replacement ratios, whereas decreased when the slag content increased or heat curing was employed. Based on the test results, a prediction model was established for the drying shrinkage of GRACs, in which the factors of recycled aggregate replacement ratio, slag content, and curing regime were involved.