Interlayer stress transfer improvement in bi-layer graphene oxide /calcium silicate hydrate via CNTs

Abstract

Previous studies have shown that the experimental values of mechanical properties of graphene oxide/calcium silicate hydrate (GO/CSH) are lower than theoretical values. The strengthening degree of graphene oxide (GO) on mechanical properties of calcium silicate hydrate (CSH) is quite different. This is mainly due to the weak interface between GO layer and CSH matrix. In order to further enhance the interlayer stress transfer and interfacial interaction between GO and CSH nanostructures, a series of CNTs are created in double GO layers to form a new double GO/CSH with different number of CNTs configuration (D-GO-CNTs/CSH nanostructures). The results show that the normalized pull-out energies and normalized shear stress values of double GO/CSH with hydroxyl groups (D-GO-OH/CSH) composites are enhanced by 26.58% and 33.33%, while the normalized pull-out energies and normalized shear stress values of double GO/CSH with epoxy groups (D-GO-Oo/CSH) are only enhanced by 14.29% and 15.38%. In addition, the CNTs leads to a greatly enhancement (about 2–3 times) in normalized interlayer stress transfer of D-GO/CSH nanostructures, while exerts a little adverse effect (about 10%) on the failure strain of D-GO/CSH nanostructures. According strain energy ratio and molecular dynamics analysis, the enhancement effects of interlayer stress transfer in D-GO/CSH model are the best when the number of CNTs is 3. It provides a new approach for actively enhancing the interlayer stress transfer and interfacial interaction of D-GO/CSH nanostructures.