Page 11 - ICJ Jan 2026

TECHNICAL PAPER

designing stronger and durable concrete. Furthermore, many investigations on the effectiveness of sacrificial anodes in
more standards are also under formulation to cater the needs of different cementitious systems for both corrosion control and
various engineering and durability properties of the concrete as corrosion prevention under carbonation induced and chloride
mentioned in section 4.3. induced corrosion environments. This research evaluates the
effectiveness of cathodic protection‑specifically sacrificial zinc
3.11 Chemical admixture evaluation anodes-in extending the service life of reinforced concrete
The evolution of chemical admixtures has arguably been the structures exposed to corrosion from chlorides and carbonation.
single most transformative development in the modernization Recognizing that conventional patch repairs often fail due to
of concrete. Originally conceived as workability aids or setting electrochemical incompatibility, the study compares sacrificial
modifiers, admixtures are now precision tools for microstructure anodes across different cementitious systems (OPC, OPC-Fly
tailoring, enabling control over hydration kinetics, particle Ash, PSC, OPC-GGBS, and ternary blends) through laboratory
dispersion, shrinkage, and pore structure formation. Admixtures and field investigations. Laboratory tests show that sacrificial
such as polycarboxylate ether (PCE) based superplasticizers, anodes significantly reduce corrosion rates in both corrosion‑
Viscosity Modifying Admixtures (VMAs), modern retarders and control and corrosion-prevention applications, with greater
accelerators which fine‑tune the induction period of hydration, gains in chloride-induced corrosion and higher effectiveness
offering precise control over setting and early strength when corrosion has not yet initiated. Performance also depends
on the initial corrosion rate, with lower initial deterioration
development in case of self-compacting concrete and rheology yielding larger service‑life improvements. A field study on a
controlled 3D printable concrete mixes.
residential building in Delhi confirmed that the installed anode
Fundamental evaluations of permeability-reducing admixtures system delivered current outputs consistent with ISO 12696
for hydrostatic (PRAH) and non-hydrostatic (PRAN) applications criteria, demonstrating effective cathodic prevention when
were conducted. The group also pioneered research on combined with complementary repair measures. Overall, the
[44]
organic and inorganic corrosion inhibitors , establishing study establishes sacrificial anodes as a practical, cost‑effective
mechanistic pathways of inhibitor-steel interaction, adsorption means to enhance durability in new and existing concrete
thermodynamics, and long-term performance under chloride structures and provides a basis for developing Indian guidelines
and carbonation exposure. Over the past decade, the group has and best‑practice specifications. The formulation of guidelines
rigorously evaluated a diverse spectrum of chemical admixtures and specifications for adoption of CP for RCC is also under
such as low, high and mid-range water reducing admixtures, discussion at the level of BIS.
retarders. extended set retarders, anti washout admixtures, Another study on the Evaluation of Concrete Surface Coatings
viscosity modifiers, permeability reducing admixtures, for their effectiveness in service life enhancement of RCC
corrosion inhibitors etc. while simultaneously pioneering elements was taken up. This study evaluates commercially
advanced techniques and methodologies for their performance available surface coatings for concrete to identify those most
assessment. These breakthroughs have paved the way for a effective in extending the service life of reinforced concrete
transformative revision of IS: 9103 as mentioned in Section 4.4. structures under typical Indian exposure conditions, especially
The proposed paradigm shifts positions the standard to chloride-induced and carbonation-induced corrosion. Four
encompass comprehensive general requirements, clearly coating types (acrylic, epoxy, polyurethane, and cementitious
defined performance benchmarks, compatibility evaluation polymer modified) along with silane‑siloxane and methyl
protocols, and robust testing methodologies. Adopting this methacrylate treatments were tested through standardized
forward-looking framework will catalyze innovation, accelerate assessments of water permeability, chloride diffusion,
research, and foster the development of next-generation carbonation resistance, adhesion, moisture control, and
chemical admixtures, ultimately elevating the technological chemical durability. Results show that epoxy and polyurethane
landscape of concrete science in India. coatings consistently offer the highest protection, outperforming
acrylic and cementitious coatings in most durability criteria,
3.12 Corrosion mitigation, cathodic protection while also providing better cost-to-performance balance. The
and concrete surface coatings study proposes threshold values and selection guidelines for

A significant line of research involved electrochemical coating performance to support inclusion in BIS standards,
characterization of steel in concrete exposed to chloride and enabling more informed, exposure‑specific coating selection for
carbonation environments. Studies developed correlations improved longevity of reinforced concrete structures in India.
between concrete chemistry, pore solution properties, corrosion 3.13 Stress‑strain characteristics of high
rate, and protection mechanisms. The group advanced strength concrete
cathodic protection (CP) methodologies for Indian conditions,
including sacrificial anode based CP systems and performance In the IS: 456 under revision, provisions are being proposed for
monitoring frameworks. NCCBM carried out experimental inclusion that specifically address the stress‑strain behaviour

90 THE INDIAN CONCRETE JOURNAL | JANUARY 2026