Repair and rehabilitation of concrete pavements Indireddy
This paper provides an overview of the current methods of analysing and repairing cracks in concrete pavements. The Finite element method (FEM) models and non-destructive analysis method, and the repairing methods using electro-deposition, electro chemical, recycled steel fibres are reviewed.
Biogenic treatment improves the durability and remediates the cracks of concrete structures
Abstract Microbially induced calcium carbonate precipitation is a naturally occurring biological process that has various applications in remediation and restoration of range of building materials. In the present study the role of bacteria Bacillus sp. on the durability properties and remediation of cracks in cementitious structures were studied. “Biocement” induced by a Bacillus sp. lead to more than 50% reduction in the porosity of mortar specimens, while chloride permeability of concrete changed from “moderate” to “very low” as indicated by rapid chloride permeability test. The bacteria successfully healed the simulated cracks of depths including 27.2 mm in cement mortars with increase in the compressive strength as high as 40% of that of control. The results clearly showed microbially induced calcium carbonate precipitation can be applied for various building materials for remediation of cracks and enhancement of durability.
USE OF ELECTRODEPOSITION FOR REPAIR OF CONCRETE WITH SHRINKAGE CRACKS
The electrodeposition method for repair of cracked reinforced concrete is presented here. Electrodeposition means precipitation of material on the surface of an electrode by electrolysis. The ultimate purpose of this study is to apply this technique to land-based reinforced concrete structures. Investigations on mortar specimens with embedded steel were conducted. After cracking the specimens with a specified load, they were immersed in several types of solutions. Then a constant current between the embedded steel in mortar and an electrode in the solution was applied. The deposition pattern on the surface, the crack closure development, and surface coating due to the precipitation of electrodeposits were checked and evaluated. In order to assess the effectiveness of this method to improve the mortar surface, water permeability, pore size distribution, and adhesion strength were measured. The results indicate that electrodeposits formed on the mortar surface are able to close the crack and coat the mortar surface. In addition, the investigations show that the deposition product can improve the microstructure of the mortar surface.