Internal Curing of Concrete by Superabsorbent Polymer Particles

This paper empirically investigates the influence of superabsorbent polymer particles (SAPP) on the internal curing of concrete. The variations of different parameters such as workability, water absorption and mechanical properties of concrete and also alkali-silica reactivity (ASR) of mortar due to the SAPP are studied in detail. The tests of water absorption and compressive strength of concrete are performed in two curing conditions: in laboratory air after 2 and 4 days of water curing. Furthermore, the microstructures of concretes are examined using X-ray diffraction meter and scanning electron microscopy. The tests are repeated with SAPP dosages of 0.5%, 1%, 1.5% and 2% by weight of cement. Results indicate that adding SAPP leads to increasing the compressive strength significantly while workability of fresh concrete and water absorption are reduced. Also, increasing the SAP dosage from 0.5 to 1.5% causes increasing the compressive strength of concrete about 3.2 to 12.6%, respectively. In addition, it is seen that increasing the volume fraction of SAPP as an internal curing material reduces the alkali-silica reaction (ASR) expansion. Analysis of electron micrograph images and X-ray diffraction analyses indicate that using SAPP reduces the porosity, and increases the intensity of portlandite formation.