The investigation of the physical properties of the lightweight concrete produced with pumice aggregate and colemanite blended cement

Within the context of this study aimed to investigate physical properties of lightweight pumice aggregate concrete produced with cement containing colemanite, lightweight concrete specimens were produced with colemanite contribution substituted in cement proportions as 0%, 0.4%, 0.6%, 0.8%, 1%, and 2%. In concrete mix, pumice obtained from Kocapınar Region in Erciş, Van Turkey was used as coarse and fine aggregates. Concrete specimens were cured into 28, 56 and 360 days and in the context of this study, the effect of colemanite contribution was examined by experimentally investigating of gamma radiation shielding properties of concrete specimens, besides it was compared with radiation shielding values calculated theoretically with WinXcom Program. Additionally porosity, capillary absorption, ultrasonic pulse velocity, compressive strength and high temperature endurance tests were applied on these specimens, and the effect of cure age on aforesaid parameters was determined. According to the obtained results, colemanite contribution improved the radiation shielding feature of lightweight concrete but there was no linear relationship between colemanite proportion (0.4-2%) and linear and mass attenuation coefficient. Especially long term curing age (360 days) enhanced linear and mass attenuation coefficient and reduced mean free path values, and it was revealed that there was an intense linear relationship between curing age and aforesaid parameters. The results were found coherent with radiation shielding theoretical calculations obtained from WinXcom. Long term curing age (360 days) reduced capillary water absorption and porosity values respectively as 23.13-43.76% and 9.6-23.8%, and at the compression strength colemanite contribution indicated improvements in long term curing age, 360 days curing age affected positively compression strength and comparing with the values of ultrasonic pulse velocity, the result were found coherent. It was observed that 28 and 56 days specimens with colemanite contribution had loss of changeable weight and compressive strength after 400oC, and at 600oC and 800oC they were closed to each other.