Overview
Structural rehabilitation encompasses the full spectrum of interventions needed to restore a deteriorated concrete structure to its design strength and intended service life. This ranges from localised concrete removal and reinstatement in spalled areas, through rebar cleaning and corrosion protection, to the application of pre-engineered repair mortars, concrete jacketing, FRP (fibre-reinforced polymer) wrapping for section strengthening, and carbonation-inhibiting protective coatings applied over the entire structure.
Prisci Constructions follows the BS EN 1504 European Standard repair principle framework — the same standard used by major petrochemical, aviation, and defence clients in India — which requires that repair materials restore concrete equivalent to or better than the original. We do not use standard site-mixed mortars for structural repair; all materials are pre-engineered systems with documented compressive strength, tensile bond, modulus of elasticity, and chloride permeability data.
Our structural rehabilitation team is led by qualified civil engineers with hands-on experience in corrosion assessment, half-cell potential testing, carbonation depth measurement, and repair design. We can act as the specialist repair contractor under your structural consultant's specification, or provide an independent assessment-to-execution service across Telangana, Andhra Pradesh, Karnataka, and Maharashtra.
Common Problems We Solve
- Concrete spalling from columns, beams, and slabs exposing corroded reinforcement bars to continued atmospheric attack
- Extensive cracking in structural members with rust staining along crack lines indicating active rebar corrosion within
- Carbonated concrete confirmed by phenolphthalein test — carbonation front has reached or breached reinforcement depth
- Chloride-contaminated concrete in coastal or industrial environments causing rapid, accelerated rebar section loss
- Delaminated concrete cover producing hollow sounds on tap-testing across beam soffits, column heads, and slab undersides
- Structural deficiency from construction error or overloading — inadequate section, missing reinforcement, or cold joint planes
Root Causes
- Carbonation of concrete alkalinity — CO2 reaction lowers pH below 9, destroying the passive oxide film protecting embedded rebar
- Chloride ingress from marine exposure, contaminated aggregate, or industrial process emissions reaching threshold concentration at rebar depth
- Insufficient concrete cover to reinforcement allowing carbonation front to reach rebar within 15–20 years of construction
- Poor original concrete quality — high water-cement ratio and inadequate curing producing permeable concrete prone to rapid carbonation
- Honey-combing from inadequate compaction during original pours, creating voids that expose rebar without any concrete cover
- Overloading from building modifications — additional floor additions, changed occupancy use, or removal of load-bearing elements without structural review
Our Approach
Full structural survey using rebound hammer, half-cell potential mapping, carbonation depth testing with phenolphthalein indicator, and visual spall mapping. Rebar corrosion activity is classified as active, passive, or uncertain across all structural elements. A condition report with quantified repair volumes is produced before any repair scope is priced or agreed.
Repair strategy is developed per BS EN 1504 principles: patch repair for localised spalls, section replacement for extensive damage, concrete jacketing for structural upgrading, and FRP wrapping for column and beam strengthening. Material systems are specified with full datasheets, mix designs, and application thicknesses documented for client and structural consultant review.
Work proceeds systematically element by element with temporary propping before concrete removal where required. Each repaired section is tested by rebound hammer and pull-off adhesion test before the protective coating is applied. A photographic record of every element — from break-out to final coat — is maintained and submitted at project close.
Materials Used
Structural repair materials must match or exceed the original concrete in strength, bond, and durability. We use only pre-engineered systems from India's leading construction chemistry manufacturers — all with published compressive strength, tensile bond strength, modulus of elasticity, and carbonation resistance data.
Our Process
Structural Condition Assessment
Rebound hammer (Schmidt hammer) tests conducted at a regular grid across all structural elements to map concrete quality. Carbonation depth measured on drilled cores using phenolphthalein pH indicator. Half-cell potential mapping (copper-copper sulphate electrode) identifies active corrosion zones before any demolition. Chloride profile testing performed in coastal or industrial environments. All data is compiled into a condition report with repair strategy recommendation and volume take-off.
Temporary Propping and Access
Where concrete is to be removed from load-bearing elements — beams, columns, or slabs — temporary propping is erected per the structural engineer's shoring design before any concrete breaking commences. Scaffolding access systems are erected for work at height. Perimeter hoarding with dust containment sheeting protects occupied areas and public spaces below the work zone.
Concrete Removal to Sound Substrate
Delaminated, carbonated, and chloride-contaminated concrete is removed by pneumatic chipping or — where vibration must be minimised in occupied buildings — by hydro-demolition (high-pressure water jet). Removal continues to a sound substrate confirmed by rebound hammer reading. Break-out is extended to a minimum 20mm behind the nearest rebar face to allow repair mortar to fully encapsulate the reinforcement bar and provide adequate cover.
Rebar Cleaning and Corrosion Protection
Exposed reinforcement is mechanically cleaned to Sa 2.5 standard (near-white metal) using angle grinder with wire cup or needle gun to remove all rust, mill scale, and contamination. Rebar section loss is measured at each bar — if cross-sectional loss exceeds 20%, supplementary lapped bars are added per the structural engineer's instruction. Rebar corrosion protection coating (Sika MonoTop-615HB or zinc-rich epoxy primer) is applied wet-on-wet before repair mortar encapsulates the bar.
Repair Mortar Application
Substrate is pre-wetted to saturated surface dry (SSD) condition. Bonding agent (Fosroc Nitobond AR or BASF Concresive Paste) is applied and allowed to become tacky before mortar placement. Pre-engineered repair mortar (Fosroc Renderoc HB40 or BASF MasterEmaco S488) is applied in layers not exceeding 50mm per pass for hand-applied work; form-and-pour systems (Renderoc HB) used for overhead repairs exceeding 150mm depth. Each layer is cured per datasheet before the next pass. Finished surface is matched to original profile.
Anti-Carbonation Protective Coating
After repair mortar achieves minimum 28-day strength, a two-coat anti-carbonation elastomeric barrier coating (BASF MasterProtect 8000CI or Fosroc Dekguard Elastic) is applied to all concrete surfaces across the structure — not limited to repaired patches alone. This is the most critical step: uncoated sound concrete will continue carbonating and initiate new corrosion cycles within 5–10 years, negating the repair investment. Coating DFT (dry film thickness) is verified by comb gauge at 1 reading per 5m².
Post-Repair Testing and Documentation
Rebound hammer tests on all repaired patches confirm strength equivalence to surrounding concrete. Pull-off adhesion tests per IS 13311 / BS EN 1542 are conducted on a minimum 5% sample of patch repairs. Complete photographic record from initial break-out through rebar condition, mortar application, and final coated finish is compiled and submitted to the client together with material delivery notes, manufacturer data sheets, and QC test results.
Frequently Asked Questions
Related Projects
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