Experimental Study On Strengthening Methods Of Stone Slabs Of Ancient Architecture

Many cities have a long history and the protection of ancient architecture which has cultural characteristics or memorable significance is meaningful to the sustainable development of the city. Natural stone material in ancient architecture has low tensile and bending strength and a long history.Due to the long history,the impact of the material degradation and the environment,stone artifacts have severely broken and weathered.In the actual project,technicians can do little to the large,ancient and heavily damaged stone,so appropriate strengthening methods are important.In this paper,mechanic properties of stone,prototype slabs and slabs with initial crack have been tested,then to the unbroken slabs,carbon fiber and steel reinforcement mesh and polymer mortar strengthening methods have been used. And to the broken stone slabs,bond strengthening method has been used and carbon fiber strengthening method has been used after bonding.The stone slabs come from Fangshan in Beijing,which are the same size with the real slabs used in ancient architecture.The effects of initial crack and the bond strengthening method have been studied by experiments.In order to analyse strengthening effects,bearing capacity,deformation and joint working performance have been compared.Load bearing capacity formulas of the prototype and strengthening stone slabs have been proposed in both cracking and failure situations.The main conclusions are as follows:1. Prototype slabs destruction is brittle failure,and the strengthening slabs show ductile failure characteristics.The fracture surface is in the pure bending moment zone or a natural defect cross-section.2. Initial cracks have no significant effect on the bearing capacity.3. The bearing capacity of both prototype and strengthening stone slabs are discrete,but the average bearing capacity of the strengthening slabs are higher than the prototype.4. The strengthening layer and the stone slabs work together well,which shows that the strengthening methods can delay cracking.5. MSR impregnating resin works well on bonding strengthening method for there is no cracking in the original sections and the slabs can reach the original bearing capacity.6. Both carbon fiber and steel reinforcement mesh and polymer mortar strengthening methods can play a good effect and do not use anchor which may damage the ancient architecture.So the two methods can be used in actual construction and strengthening work.