Health Assessment and Rehabilitation of an Existing Stone Masonry Dam - A Case Study

Abstract

Repair and Rehabilitation is an important activity linked to the durability requirement of civil structures. The hydraulic structures face severe service environment such as sulphate attack, chloride attack, freezing thawing cycles, temperature gradients, static and dynamic forces and Alkali Aggregate Reactivity. The rehabilitation schemes have been developed and are implemented in concrete hydraulic structures based on Field Quality Assurance Plan (FQAP) covering the detailed rehabilitation measures. However, India is having more than five thousand number of old dams including stone masonry dams and most of the aging stone masonry dams are necessitating repair and rehabilitation. This paper illustrates the challenges faced during the comprehensive repair and rehabilitation of more than 100 years old stone masonry dam under Dam Rehabilitation and Implementation Scheme (DRIP-I). The present study systematically describes about the rehabilitation scheme and the measures specially the execution of crystalline repair mortar, dam body grouting and water permeability test (WPT) implemented to reinstate the structure.

Introduction

Most old dams in India are earthen or stone masonry structures, many constructed around a century ago using lime-surkhi mortar. These dams are exposed to weathering, wet-dry cycles, UV radiation, and chemical attacks, which make maintenance and rehabilitation challenging, particularly in ensuring joints are properly filled with waterproof mortar.

The study focuses on the rehabilitation of Chandpatha Dam in Shivpuri, Madhya Pradesh, built between 1915–1918. The 2164?m long stone masonry dam supplies drinking and irrigation water via Madhav Lake. Major issues included seepage/leakage, blocked sluice gates, and safety hazards. Rehabilitation under the Dam Rehabilitation and Implementation Project (DRIP-I) involved:

1. Visual inspection to identify seepage zones.
2. Pointing with standard and crystalline repair mortars for low to high seepage areas.
3. Grouting with cementitious and low-viscosity polyurethane (PU) grout in critical reaches.
4. Installation of automated gates, handrails, and structural improvements.

Materials used included high-strength crystalline repair mortar, a two-component epoxy bonding agent for mortar-rock adhesion, and PU-based polymeric grouts to fill fine cracks and voids. Procedures emphasized careful surface preparation, anti-fungal treatment, mortar compaction, and curing.

Investigations assessed mortar properties and grouting efficacy using tests like Slant Shear Test, rapid chloride permeability, abrasion resistance, compressive and tensile strength, ensuring the repair materials provide durable, watertight joints.

Conclusion

The present study demonstrates the rehabilitation process adopted for aging stone masonry dam. The methodology and material properties are also discussed based on in-situ and laboratory investigations. The major challenges in case of stone masonry dams are to endure the earlier construction i.e. old masonry joints while performing the rehabilitation activities. The activities such as pressure grouting were performed on suitable pressure which plugs the existing voids and cavities and in addition does not cause any damage to the joints having adequate performance. It is pertinent that with the present rehabilitation scheme the water seepage from dam body in all reaches has brought down to safer limits as per the technical specifications. Moreover, the cutting of grooves for repair are performed with utmost precautions to avoid the damages in nearby zones. The critical reaches having higher rate of seepages were repaired by horizontal pressure grouting using Poly Urethane (PU) based grouting material which expands when comes in contact with water. This rehabilitation scheme also provides a way forward to the future rehabilitation works for stone masonry dams. It is also important to consider the fact that not much non-destructive technique is found seemly to gauge the defects in masonry dams as most of the methods are either having depth or thickness constraints or suitable for materials like concrete. In addition, considering the restraint such as non-availability of design drawings and QC documentation, the visual inspection methods like physical inspection can be proven, moreover instruments like borescope and video scope can also be utilized for in depth monitoring of narrow cavities, joints and cracks.

References

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Copyright

Copyright © 2026 Nisheeth Agnihotri, Ravi Agarwal, N. P. Honkanadavar. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.