Effect of geogrid reinforcement on the drying shrinkage and thermal expansion of geopolymer concrete

The effect of triaxial geogrid reinforcement on the thermal expansion and drying shrinkage of geopolymer concrete (GPC) was experimentally investigated. Three groups of GPC prism specimens with a length of 280 mm and a cross-section of 75 mm x 75 mm were prepared and tested in this study. The first group included six unreinforced GPC specimens and was considered as the control group of specimens. The second group included six GPC specimens reinforced with one layer of geogrid. The third group included six GPC specimens reinforced with two layers of geogrid. The triaxial geogrid reinforcement was placed at a depth of 37.5 mm from the surface of the specimen. The tests were carried out by drying the GPC specimens in a controlled environmental chamber at a temperature of 27 +/- 4 degrees C and a relative humidity of 50 +/- 10% for 98 days. It was found that the geogrid significantly reduced the thermal expansion and drying shrinkage of GPC specimens. The thermal expansion and drying shrinkage were less in the GPC specimens reinforced with two layers of geogrid compared to the GPC specimens reinforced with one layer of geogrid. It was also found that the rate of thermal expansion and drying shrinkage of the GPC specimens reinforced with geogrid was lower than that of the control unreinforced GPC specimens.