The Optimum Interval Time of Layered Cement Composites with the Incorporation of Edge-Oxidized Graphene Oxide

The current research focuses on the effect of incorporating edge-oxidized graphene oxide (EOGO) on the performance of layered cement composites cast at different times. The feature of producing flower-shaped hydrated cement products is exploited to enhance the contact surface of two different cement composites. In the current study, the interval time of casting cement composites is the crucial parameter investigated. Consequently, a layer of cement paste with EOGO is cast above a layer of cement mortar where the amount of EOGO of 0.10% by the cement weight is fixed for all mixtures. Also, four different interval times based on cement setting time are considered, namely immediately, 6 h, 12 h, and 1 day. Similar mixtures are prepared but without adding EOGO for comparison purposes. The results show that EOGO is capable of enhancing the contact surface of layered cement composites by strengthening the split strength of two different layers (between 12 and 29%). Moreover, casting the paste layer containing EOGO after 6 h of mortar layer seems to be the optimum interval time among others by improving compressive strength (by 29%) and residual strength (by 34%) and not affecting flexural strength and porosity percentage.