Understanding the mechanical behaviour of Calcium Silicate Hydrate (CSH) is a key to fundamental and engineering advances in improving the performance of cementitious materials. It is well known that CSH exists in two forms that low-density CSH (LD CSH) and high-density CSH (HD CSH). Herein, this paper focuses on transversely isotropic properties of two form of CSH using nanoindentation technique, finite element (FE) analysis, dimensional analysis and artificial neural networks (ANNs) with microporomechanics to investigate its elastic properties, packing density and cohesive strength properties. The finding of this paper demonstrates that nanoindentation technique could reveal the transversely isotropic properties of materials and its elementary solid in elasticity and strength behaviour. The obtained results show that the solid elementary present in CSH possesses an isotropic elasticity behaviour and anisotropic strength behaviour.