Textile-Reinforced Concrete for Enhancing the Flexural Performance of Reinforced Concrete Beams in India: Effects of Textile Configuration, Concrete Strength, Reinforcement Ratio, Loading Conditions, and Environmental Exposure

1.Introduction
Reinforced concrete structures are designed to provide long-term structural safety and serviceability[1]; however, their performance inevitably changes during prolonged service. Aging, environmental deterioration, physical actions, excessive loads, inadequate construction, design deficiencies, changes in functional requirements, natural hazards, and accidental events can produce cracking, stiffness reduction, reinforcement deterioration, and loss of load-carrying capacity. [2.3] Consequently, strengthening and rehabilitation have become important components of modern structural engineering[4].
Conventional strengthening techniques can provide substantial increases in structural capacity[5], but they may introduce limitations related to construction thickness, corrosion, compatibility, fire resistance, durability, and installation complexity[6]. Steel-based strengthening systems, for example, require adequate protection against corrosion[7]. Fiber-reinforced polymer systems provide high strength and corrosion resistance but normally rely on organic resin matrices[8], which may create concerns related to temperature, fire, substrate compatibility, and inspection of hidden damage[9].
Textile-reinforced concrete provides an alternative cement-based strengthening technology[10]. TRC combines a fine-grained cementitious matrix with continuous textile reinforcement[11]. The reinforcement can consist of carbon, alkali-resistant glass, basalt, aramid, or other high-performance fibers[12]. Because textile reinforcement is resistant to corrosion compared with conventional steel reinforcement, TRC can be particularly attractive for strengthening structures exposed to aggressive environments[13].
The structural effectiveness of textile-based cementitious composites depends strongly on the interaction between the textile, matrix, and existing concrete[14]. Textile geometry, yarn spacing, number of layers, surface treatment, impregnation, anchorage, matrix properties, and textile-to-matrix bond can significantly influence the overall mechanical response[15]. Previous research has demonstrated that textile configuration and matrix–textile bonding affect strength, ductility, toughness, and crack development[16].
Flexural strengthening of RC beams with textile-based cementitious composites has received increasing attention[17]. Experimental and numerical studies have investigated different textile materials, mortar systems, numbers of layers, and anchorage configurations[18]. Four-point bending has frequently been used to evaluate cracking, stiffness, yielding, ultimate capacity, and failure mechanisms[19].
For India, the issue is particularly relevant because reinforced concrete infrastructure is exposed to substantially different climatic and environmental conditions[20]. Coastal structures can experience chloride exposure, while other regions experience high temperature, seasonal moisture variations, carbonation, sulfate exposure, or combinations of environmental actions[21]. Indian standards and technical documents recognize the importance of exposure conditions and durability-related properties such as permeability and resistance to chloride ingress[22].
Accordingly, the present study develops an India-oriented framework for evaluating TRC-strengthened RC beams. The principal variables are textile configuration, concrete strength, conventional reinforcement ratio, loading conditions, bond and anchorage, polypropylene-fiber modification, and environmental exposure.
The specific objectives are:
    To evaluate the effect of TRC strengthening on the flexural behavior of RC beams.
    To investigate the influence of one and two textile layers.
    To examine the effects of textile surface treatment.
    To evaluate the contribution of U-shaped shear pins and hooks.
    To investigate polypropylene-fiber modification of the fine-grained concrete.
    To assess the influence of interface-agent application.
    To quantify changes in cracking load, yielding load, ultimate load, deflection, and crack width.
    To examine the relationship between textile reinforcement and conventional steel reinforcement.
    To establish a theoretical framework for calculating the flexural response of TRC-strengthened beams.
    To extend the framework to Indian environmental exposure conditions.
2. Literature Background
2.1 Textile-Reinforced Concrete
TRC is a cement-based composite in which continuous textile reinforcement is embedded within a fine-grained cementitious matrix[23]. The use of continuous textile yarns permits reinforcement to be distributed across a thin layer while maintaining a relatively high tensile capacity[24].
The principal advantage of TRC for strengthening is that a relatively thin layer can be placed on an existing concrete surface without substantially modifying the original cross-sectional dimensions[25]. Textile-based strengthening systems can also conform to complex surfaces and can be installed using relatively conventional cement-based construction techniques[26].
However, the mechanical performance of TRC depends on effective stress transfer between the textile and matrix[27]. The complex geometry of multifilament yarns and the interaction between transverse and longitudinal yarns make textile–matrix bonding substantially more complicated than the bond of a conventional reinforcing bar[28].
2.2 Flexural Strengthening of RC Beams
For flexural strengthening, the TRC layer is normally placed in the tensile region of the beam[29]. Under increasing bending load, the strengthening system passes through several stages[30]:
    elastic behavior;
    cracking of the original concrete;
    redistribution of tensile stresses;
    increased participation of the steel reinforcement and textile;
    yielding of conventional tensile reinforcement;
    development of large deformation;
    textile rupture, concrete crushing, or another governing failure mechanism.
The efficiency of strengthening therefore cannot be evaluated solely from ultimate load. Cracking load, crack width, crack spacing, stiffness, ductility, and energy absorption must also be considered[31].
Recent experimental research continues to demonstrate the importance of textile configuration and anchorage[32]. Hybrid anchorage systems have been reported to improve bonding, cracking behavior, ductility, and energy dissipation in TRC-strengthened beams[33].
2.3 Bond and Anchorage
The interface between the existing concrete and TRC layer represents a critical load-transfer zone[34]. Poor bond can result in premature debonding, limiting the utilization of textile tensile capacity[35].
Surface preparation, textile impregnation, sand coating, mechanical anchorage, and shear connectors can therefore influence the effective contribution of TRC[36].
In the present framework, bond is represented through:
    textile surface treatment;
    epoxy impregnation;
    fine-sand or coarse-sand coating;
    interface-agent application;
    U-shaped shear pins;
    U-shaped textile hooks.
3. India-Oriented Research Framework
The proposed framework considers six principal groups of variables.
Table 1. Research variables
Variable group    Main variables
Textile configuration    Number of textile layers, textile type, mesh geometry, textile surface treatment
Concrete properties    RC concrete strength, fine-grained concrete strength, matrix composition
Reinforcement    Steel reinforcement ratio, textile reinforcement ratio
Bond/anchorage    Epoxy impregnation, sand coating, interface agent, U-shaped pins, U-shaped hooks
Loading    Four-point bending, cracking load, yielding load, ultimate load
Environmental exposure    Chloride, carbonation, moisture, temperature, sulfate exposure
The environmental component is treated as an extended design variable, rather than as a measured experimental variable in the original dataset.
4. Materials and Experimental Program
4.1 Experimental Specimens
The original experimental program consisted of 14 RC beams.
The beam cross-section was:
b×h=120×210"  " mm
The beam span was 2,000 mm, with a net span of 1,800 mm.
The tensile reinforcement consisted of two 12-mm-diameter HRB335 bars. The concrete cover was 25 mm, including the fine-grained concrete and textile strengthening layer.
The transverse reinforcement consisted of 6.5-mm-diameter HPB235 stirrups at 80-mm spacing, with no stirrups in the pure bending region.
The original concrete was C40 with a measured compressive strength of approximately 45 MPa, while the fine-grained concrete had a compressive strength of approximately 55 MPa.
5. Textile Reinforcement
The textile consisted of orthogonally arranged carbon and E-glass yarns.
The carbon textile was based on T700S 12k yarn, while the E-glass yarn was 4k.
Table 2. Mechanical and geometric properties of textile yarns
Parameter    Carbon T700S 12k    E-glass 4k
Monofilament tensile strength (MPa)    4660    3200
Elastic modulus (GPa)    231    65
Ultimate elongation (%)    2.0    4.5
Yarn linear mass (Tex)    801    600
Density (g/cm³)    1.78    2.58
The textile mesh spacing was 10 mm.
Epoxy impregnation was used to improve yarn integrity and interaction with the fine-grained concrete. The experimentally measured properties of the impregnated carbon yarn included an ultimate tensile strength of approximately 4,100 MPa, an elastic modulus of approximately 180 GPa, and an ultimate strain of approximately 0.023.
6. Fine-Grained Concrete
The fine-grained concrete consisted of Portland cement, fly ash, silica fume, water, superplasticizer, and fine aggregate.
Table 3. Fine-grained concrete mix
Constituent    Content
Portland cement PII52.5R    472 kg/m³
Fly ash    168 kg/m³
Silica fume    35 kg/m³
Water    262 kg/m³
Superplasticizer    3.25 kg/m³
Water-to-binder ratio    0.40
Sand, 0–0.6 mm    460 kg/m³
Sand, 0.6–1.2 mm    920 kg/m³
The measured compressive strength of the fine-grained concrete was approximately 55 MPa.
7. Specimen Configuration
The original beam matrix was designed to investigate the effects of:
    textile layer number;
    textile surface treatment;
    polypropylene fibers;
    interface agent;
    U-shaped shear pins;
    U-shaped textile hooks.
Table 4. Experimental configuration
Specimen    Textile treatment    Layers    PP fiber (kg/m³)    Interface agent    U-pin    U-hook
Beam1    None    0    0    No    No    No
Beam2    None    0    0    No    No    No
Beam3    Epoxy, no sand    1    0    No    No    No
Beam4    Epoxy, no sand    1    0    Yes    No    No
Beam5    Epoxy, no sand    2    0    No    Yes    Yes
Beam6    Epoxy + fine sand    1    0    No    No    No
Beam7    Epoxy + fine sand    1    0    Yes    No    No
Beam8    Epoxy + fine sand    2    0    Yes    Yes    Yes
Beam9    Epoxy + coarse sand    1    0    No    No    No
Beam10    Epoxy + coarse sand    1    0    Yes    No    No
Beam11    Epoxy + coarse sand    1    1.0    No    No    No
Beam12    Epoxy + coarse sand    1    1.0    Yes    No    No
Beam13    Epoxy + coarse sand    1    1.0    No    Yes    No
Beam14    Epoxy + coarse sand    1    1.0    Yes    Yes    No

8. Strengthening Procedure
The RC beams were initially cast and cured for 28 days. The surface was then mechanically roughened and cleaned.
For specimens requiring mechanical anchorage, holes were drilled into the existing concrete surface. U-shaped shear pins were subsequently installed using structural adhesive.
The textile was tensioned and fixed to the beam surface. Fine-grained concrete was then applied to form the strengthening layer.
For two-layer configurations, the second textile layer was installed after placing an intermediate fine-grained concrete layer.
The textile was positioned approximately 2–3 mm from the strengthening surface, while the external fine-grained concrete cover over the outer textile was approximately 3–5 mm. The total strengthening thickness was approximately 10 mm.
This thin strengthening configuration is particularly relevant for rehabilitation applications where increasing the original beam dimensions is undesirable.

9. Loading and Measurement
Four-point bending was used.
The distance between the two loading points was 600 mm, defining the pure bending region.
The tests were conducted using a 5,000-kN hydraulic servo-controlled testing machine under incremental loading.
Measurements included:
    load;
    tensile strain;
    concrete compression strain;
    textile strain;
    mid-span deflection;
    support deformation;
    crack width;
    cracking load;
    yielding load;
    ultimate load.
Two LVDTs were used to measure mid-span deflection, while additional LVDTs monitored support deformation.
10. Experimental Results
Table 5. Experimental load, crack-width, and deflection results
Beam    Pcr (kN)    wcr (mm)    Py (kN)    Dy (mm)    wy (mm)    Pu (kN)
Beam1    10.8    0.04    48.6    5.5    0.80    58.6
Beam2    9.8    0.03    48.9    6.0    1.20    59.0
Beam3    12.1    0.01    52.8    6.2    0.40    63.9
Beam4    12.1    0.01    52.3    5.8    0.36    61.6
Beam5    12.2    0.01    55.0    6.0    0.24    73.0
Beam6    12.2    0.01    54.5    5.7    0.42    64.4
Beam7    12.7    0.01    52.5    7.3    0.40    60.2
Beam8    13.8    0.01    58.8    7.5    0.38    74.6
Beam9    12.5    0.01    53.2    6.1    0.34    62.8
Beam10    12.3    0.01    53.5    6.3    0.40    63.7
Beam11    12.9    0.01    54.6    6.5    0.42    63.7
Beam12    12.9    0.01    53.0    6.0    0.38    63.2
Beam13    12.5    0.01    55.2    5.9    0.30    65.4
Beam14    12.6    0.01    55.3    6.5    0.34    65.1

11. Effect of TRC Strengthening
The mean ultimate load of the two control beams was:
P_(u,control)=(58.6+59.0)/2=58.8" " kN
The corresponding mean yielding load was:
P_(y,control)=(48.6+48.9)/2=48.75" " kN
Beam8 reached an ultimate load of 74.6 kN. Therefore:
ΔP_u=(74.6-58.8)/58.8×100=26.87%
The corresponding yielding-load increase was:
ΔP_y=(58.8-48.75)/48.75×100=20.62%
Thus, within the tested configuration, the two-layer TRC system with fine-sand treatment and mechanical anchorage produced the largest measured load-carrying response.
12. Crack Control
The control specimens exhibited substantially larger crack widths than the TRC-strengthened specimens.
Beam2 developed a maximum crack width of 1.20 mm at yielding, whereas Beam8 had a maximum crack width of only 0.38 mm at a substantially higher yielding load.
The reduction relative to Beam2 was:
(1.20-0.38)/1.20×100=68.3%
This demonstrates the importance of the textile layer in controlling crack opening.
The textile provides distributed tensile restraint after concrete cracking and contributes to the redistribution of tensile stresses. The result is a larger number of narrower cracks rather than a small number of rapidly widening cracks.
13. Effect of Textile Surface Treatment
Comparison between the textile configurations demonstrates that surface treatment can influence the interaction between the textile and fine-grained concrete.
For two-layer specimens, Beam5 and Beam8 had ultimate loads of 73.0 and 74.6 kN, respectively.
The increase was:
(74.6-73.0)/73.0×100=2.19%
The yielding load increased from 55.0 to 58.8 kN:
(58.8-55.0)/55.0×100=6.91%
The maximum crack width remained below 0.40 mm in both cases, but the fine-sand treatment provided stronger load development and improved textile–matrix interaction.
This finding is consistent with the broader understanding that textile geometry and yarn–matrix bonding are fundamental parameters governing TRC performance[37.38].
14. Effect of Polypropylene Fibers
The addition of 1.0 kg/m³ polypropylene fiber was primarily intended to improve the early cracking behavior and toughness of the fine-grained matrix.
The experimental data indicate that PP fibers did not produce a major increase in post-cracking flexural behavior in the thin TRC layer.
For example, Beam9 and Beam11 had ultimate loads of 62.8 and 63.7 kN, respectively.
The corresponding increase was:
(63.7-62.8)/62.8×100=1.43%
Nevertheless, polypropylene fibers can reduce early microcracking and improve the toughness of the cementitious matrix. Their principal contribution in this configuration therefore appears to be related to matrix integrity and crack initiation rather than a major increase in ultimate flexural capacity.
15. Effect of U-Shaped Shear Pins
Mechanical anchorage had a more pronounced structural effect than the interface agent.
Beam11 and Beam13 provide a useful comparison. The yielding load increased from 54.6 to 55.2 kN:
ΔP_y=1.10%
while the ultimate load increased from 63.7 to 65.4 kN:
ΔP_u=2.67%
The maximum crack width decreased from 0.42 to 0.30 mm.
The principal contribution of mechanical anchorage is therefore associated with improved composite action between the strengthening layer and the original concrete substrate.
Recent TRC research similarly identifies anchorage and bond as important factors governing strengthening efficiency, ductility, and damage development[39].
16. Effect of Interface Agent
The interface agent had a relatively limited effect on global beam performance.
For example, comparison of Beam9 and Beam10 gives:
    yielding load: 53.2 → 53.5 kN;
    ultimate load: 62.8 → 63.7 kN.
The ultimate-load increase was approximately:
(63.7-62.8)/62.8×100=1.43%
The splitting tensile tests provide additional evidence.
Table 6. Splitting tensile test results
Condition    Specimen results (kN)    Mean (kN)    Strength (MPa)
Without interface agent    63.47, 80.13, 70.14, 53.71    66.86    2.971
With interface agent    63.83, 72.33, 57.32, 76.08    67.39    2.995
The difference in average interface strength was small:
(2.995-2.971)/2.971×100≈0.81%
This indicates that when a high-performance fine-grained concrete is used and the existing concrete surface is adequately roughened, mechanical anchorage may be more influential than an additional interface-agent layer.
17. Effect of Textile Layer Number
The number of textile layers represents one of the most important variables in the strengthening system.
Beam5 and Beam8, which incorporated two textile layers, achieved ultimate loads of 73.0 and 74.6 kN, respectively. These were substantially higher than the corresponding one-layer specimens.
The highest measured yielding load was 58.8 kN for Beam8.
The experimental trend demonstrates that increasing textile reinforcement can increase:
    flexural stiffness;
    cracking resistance;
    yielding load;
    ultimate capacity;
    crack-control efficiency.
However, textile quantity cannot be increased indefinitely. Excessive textile reinforcement may result in inefficient material utilization and can shift the governing failure mechanism toward compression failure or interfacial failure.
Therefore, an optimum textile reinforcement ratio must be established rather than simply maximizing the number of layers.
18. Reinforcement Ratio as a Governing Variable
The contribution of TRC cannot be evaluated independently of the existing steel reinforcement ratio.
The total tensile resistance can conceptually be represented as:
T_total=T_s+T_f
where:
    T_s= tensile resistance provided by conventional steel reinforcement;
    T_f= tensile resistance provided by textile reinforcement.
The relative contribution can be expressed through an effective textile-to-steel reinforcement ratio:
ρ_tf=A_f/bh
and:
ρ_s=A_s/bd
where A_fis the effective textile area, A_sis the steel reinforcement area, bis beam width, his total beam depth, and dis effective depth.
The experimental evidence indicates that the effectiveness of surface treatment and additional textile layers depends partly on the amount of conventional reinforcement already present.
19. Loading Conditions
Four-point bending provides a relatively controlled pure bending region and allows the independent observation of cracking, yielding, and ultimate response.
The response can be divided into three principal stages.
Stage I: Uncracked response
The concrete, steel, and TRC layer behave approximately elastically.
Stage II: Cracked response
After concrete cracking, tensile stress is redistributed toward the steel reinforcement and textile.
Stage III: Post-yield response
Once the steel reinforcement approaches yielding, the textile becomes increasingly important in controlling crack growth and deformation.
This staged response explains why the effect of TRC is often more apparent in crack control and post-cracking stiffness than in the initial elastic response.
20. Environmental Exposure and Indian Application
The original experimental program did not include accelerated chloride, carbonation, sulfate, temperature, or wet–dry exposure tests. Therefore, environmental exposure is introduced here as an India-oriented extension of the research framework, not as an experimentally measured variable in the 14-beam dataset.
This distinction is essential for avoiding unsupported experimental claims.
Indian reinforced concrete structures can encounter substantially different exposure environments. Coastal structures are particularly relevant to chloride ingress, while other regions may experience high temperatures, seasonal humidity variation, carbonation, and sulfate-related deterioration.
Indian technical standards emphasize durability, exposure conditions, concrete quality, permeability, and chloride resistance[40].
Accordingly, the proposed environmental variable can be expressed as:
E=f(Cⓜ,Hⓜ,Tⓜ,Sⓜ,CO_2 )
where:
    C= chloride exposure;
    H= humidity/moisture variation;
    T= temperature exposure;
    S= sulfate exposure;
    CO_2= carbonation environment.
A future experimental program in India should expose TRC-strengthened beams to representative environments and compare their residual flexural properties with unexposed specimens.
21. Proposed Indian Environmental Exposure Matrix
Table 7. Proposed environmental-extension framework
Exposure condition    Principal deterioration mechanism    Main expected indicator
Coastal    Chloride ingress    Steel corrosion, cracking
Hot–humid    Moisture and temperature cycling    Bond and durability
Hot–dry    Thermal and drying effects    Matrix cracking
Urban    Carbonation and pollution    Carbonation depth
Sulfate-rich    Sulfate attack    Matrix deterioration
Wet–dry cycling    Moisture-induced deterioration    Interface degradation
This framework is consistent with the broader durability concern that chloride attack can initiate reinforcement corrosion and subsequent cracking and spalling in reinforced concrete. 
22. Theoretical Model
22.1 Basic Assumptions
The analytical model adopts the following assumptions:
    Plane sections remain plane after bending.
    Perfect strain compatibility is assumed between the strengthening layer and RC beam unless interfacial failure occurs.
    The curvature remains approximately constant within the pure bending region.
    The bending moment is related to the curvature through the sectional constitutive response.
    Tensile concrete contribution after extensive cracking is neglected or simplified.
    Textile tensile resistance is included through a textile stress–strain relationship.
    Steel reinforcement follows an elastic–perfectly plastic idealization.
23. Textile Constitutive Relationship
The tensile stress of the textile can be represented by a bilinear relationship.
For:
0≤ε_ft≤ε_fy
σ_f=E_f ε_ft
For:
ε_fy<ε_ft≤ε_fu
σ_f=σ_fy+(σ_fu-σ_fy)/(ε_fu-ε_fy ) (ε_ft-ε_fy )
where:
    E_f= effective textile elastic modulus;
    σ_f= textile tensile stress;
    ε_ft= textile strain;
    σ_fy= textile stress at the transition point;
    σ_fu= textile ultimate tensile strength;
    ε_fy= transition strain;
    ε_fu= ultimate textile strain.
For the original carbon textile system:
ε_fu≈0.021
and:
σ_fu≈3900" " MPa
were adopted in the original analytical framework.
24. Sectional Equilibrium
At a prescribed tensile strain, the strain distribution across the beam depth can be established from the plane-section assumption.
Force equilibrium is:
∫_0^(h_c)▒b σ_c (x)" " dx-∫_0^(h_t)▒b σ_t (x)" " dx-σ_s A_s-∑_(i=1)^n▒σ_fi  A_fi=0
where:
    h_c= compression-zone depth;
    h_t= tensile-zone depth;
    σ_c= concrete compressive stress;
    σ_t= tensile stress;
    σ_s= steel stress;
    A_s= steel area;
    σ_fi= stress in textile layer i;
    A_fi= effective textile area of layer i;
    n= number of textile layers.
The bending moment is obtained from:
M=∫_0^(h_c)▒b σ_c (x)x" " dx+∫_0^(h_t)▒b σ_t (x)x" " dx+σ_s A_s (h_0-h_c )+∑_(i=1)^n▒σ_fi  A_fi (h_fi-h_c )
25. Cracking, Yielding, and Ultimate States
The cracking moment is obtained when:
ε_t=ε_t0
where ε_t0is the concrete cracking strain.
The yielding moment is obtained when:
ε_s=ε_y
where ε_yis the steel yield strain.
The ultimate state is governed by the interaction between textile tensile resistance and compression-zone concrete capacity.
The original model used:
h_cu=(3ε_cu (f_y A_s+σ_fu A_f ))/(f_c b(3ε_cu-ε_0 ) )
where:
    h_cu= compression-zone depth at failure;
    ε_cu= ultimate concrete compression strain;
    f_y= steel yield stress;
    A_s= steel reinforcement area;
    σ_fu= textile ultimate stress;
    A_f= effective textile area;
    f_c= concrete compressive strength;
    b= beam width;
    ε_0= reference concrete strain parameter.
The ultimate bending moment can then be calculated from the moment-equilibrium equation.
26. Deflection Calculation
The maximum mid-span deflection can be obtained from the moment–curvature relationship.
For the four-point bending configuration:
ω_C=∫_C^A▒r ϕ(r)" " dx
where:
    ω_C= mid-span deflection;
    r= distance from the mid-span reference;
    ϕ(r)= curvature.
The use of the complete moment–curvature relationship allows the nonlinear load–deflection response to be reconstructed.
27. Comparison Between Experimental and Theoretical Results
The original analytical comparison considered:
    Beam3;
    Beam6;
    Beam9;
    Beam13;
for one textile layer, and:
    Beam5;
    Beam8;
for two textile layers.
The experimental and theoretical load–deflection responses were reported to show good agreement. The original study reported errors below 5% for the calculated yielding and ultimate loads.
This level of agreement indicates that a sectional approach based on strain compatibility and force equilibrium can provide a useful first-order analytical framework for TRC-strengthened beams.
Nevertheless, a more advanced model should explicitly incorporate:
    bond-slip;
    textile–matrix interaction;
    crack spacing;
    tension stiffening;
    anchorage;
    textile layer spacing;
    environmental degradation.
28. Comparative Performance of the Beam Groups
Table 8. Selected performance comparisons
Comparison    Main finding
Control vs TRC    TRC increased cracking, yielding, and ultimate resistance
One vs two textile layers    Two layers generally provided greater capacity
No sand vs sand treatment    Surface treatment improved textile–matrix interaction
No anchorage vs U-pins    Mechanical anchorage improved composite action
No PP vs PP    PP primarily improved matrix toughness and early cracking behavior
Interface agent vs no agent    Global beam response changed only slightly
Control vs TRC    Crack widths were substantially reduced
TRC vs control    Post-cracking behavior became more stable

29. Discussion
The experimental evidence demonstrates that TRC can provide significant flexural strengthening without requiring a substantial increase in beam dimensions.
The control beams reached ultimate capacities of 58.6 and 59.0 kN, while the highest strengthened-beam value was 74.6 kN. This represents a 26.9% increase relative to the average control capacity.
The improvement was accompanied by a substantial reduction in crack width. This is particularly important because structural serviceability is often governed by crack control before ultimate strength is reached.
The findings also demonstrate that textile quantity must be optimized. Increasing the textile layers increased load-carrying capacity, but the strengthening system should not be designed simply by maximizing textile volume. An excessively reinforced tensile layer can change the failure mechanism and reduce the efficiency of material utilization.
Bond is equally important. The textile cannot contribute its full tensile capacity unless stresses can be transferred efficiently through the matrix and the existing concrete substrate. This explains the positive role of sand treatment and mechanical anchorage.
The limited influence of the interface agent is also informative. If the existing concrete surface is properly roughened and a high-performance fine-grained matrix is used, the additional interface agent may provide only a marginal increase in global flexural capacity.
This observation has practical implications for construction because eliminating unnecessary interface-treatment steps can simplify strengthening operations.
30. Significance for Indian RC Infrastructure
The proposed India-oriented framework is particularly relevant for:
    bridges;
    parking structures;
    industrial buildings;
    coastal infrastructure;
    water-related structures;
    transportation infrastructure;
    aging residential and commercial RC buildings.
TRC is potentially attractive in these applications because its cementitious matrix is compatible with concrete substrates, while textile reinforcement offers high tensile capacity without the corrosion susceptibility associated with conventional steel reinforcement.
Recent studies continue to investigate TRC/FRCM strengthening in terms of flexural capacity, serviceability, ductility, and failure mode, supporting the relevance of textile-based cementitious systems for structural rehabilitation [41].
31. Sustainability Considerations
TRC strengthening can contribute to sustainable structural rehabilitation by extending the service life of existing structures instead of replacing them.
The sustainability benefits can include:
    reduced demolition;
    reduced consumption of new structural concrete;
    reduced construction waste;
    reduced strengthening thickness;
    improved durability;
    potential reduction in maintenance frequency;
    longer structural service life.
The sustainability advantage should nevertheless be evaluated through a complete life-cycle assessment that includes textile production, cement consumption, transportation, installation, maintenance, and end-of-life considerations.
32. Proposed Design Optimization Framework
An optimized TRC strengthening system should simultaneously consider:
"Capacity"+"Serviceability"+"Ductility"+"Bond"+"Durability"+"Constructability" 
A conceptual optimization function can therefore be written as:
F_opt=w_1 P_u+w_2 P_y-w_3 w_cr+w_4 D-w_5 C
where:
    P_u= ultimate load;
    P_y= yielding load;
    w_cr= crack width;
    D= durability indicator;
    C= strengthening cost;
    w_i= weighting factors.
The weights should be selected according to the intended application rather than assumed universally.
33. Proposed Environmental-Durability Research Program for India
To experimentally validate the environmental variable introduced in this study, future Indian testing should include at least four exposure groups:
Group A: Reference
No accelerated exposure.
Group B: Chloride exposure
Repeated chloride solution or salt-water cycles representative of coastal conditions.
Group C: Wet–dry and temperature cycles
Alternating moisture and temperature conditions.
Group D: Carbonation/sulfate exposure
Accelerated carbonation and/or sulfate exposure.
After exposure, the beams should be tested under four-point bending and evaluated for:
    residual cracking load;
    residual yielding load;
    residual ultimate load;
    stiffness;
    crack width;
    crack spacing;
    textile–matrix bond;
    steel corrosion;
    mass loss;
    carbonation depth;
    chloride penetration.
This would convert the environmental variable from a conceptual extension into a directly measurable experimental parameter.
34. Limitations
Several limitations should be recognized.
First, the experimental database was originally developed using a relatively small number of beam specimens.
Second, the environmental-exposure variable was not experimentally tested in the original dataset.
Third, the experimental beams were based on a specific cross-section, reinforcement configuration, concrete strength, and textile system. Therefore, the results should not be generalized to every RC beam configuration.
Fourth, the analytical model assumes idealized strain compatibility and does not fully reproduce bond-slip mechanisms.
Fifth, the textile properties can differ substantially according to fiber type, yarn geometry, impregnation, coating, and manufacturing process.
Sixth, environmental durability should be validated using Indian exposure conditions rather than inferred solely from mechanical tests.
35. Conclusions
Based on the experimental evidence and the India-oriented analytical framework, the following conclusions can be drawn:
    TRC is an effective thin-layer strengthening system for RC beams. The experimental results demonstrate improvements in cracking resistance, yielding load, ultimate capacity, stiffness, and crack control.
    The highest experimental ultimate load was 74.6 kN, obtained for Beam8, compared with an average control-beam ultimate capacity of 58.8 kN. This corresponds to an increase of approximately 26.9%.
    The highest yielding load was 58.8 kN, compared with an average control value of 48.75 kN, corresponding to an increase of approximately 20.6%.
    TRC substantially reduced crack width. Beam2 reached a maximum crack width of 1.20 mm at yielding, whereas Beam8 reached only 0.38 mm despite carrying a considerably higher yielding load.
    Increasing textile layers improved structural performance. Two-layer configurations generally produced greater yielding and ultimate capacities than one-layer systems.
    Textile surface treatment improved composite interaction. Sand-coated textile configurations showed improved utilization of the textile reinforcement and more effective crack control.
    Mechanical anchorage improved composite action. U-shaped shear pins reduced the possibility of relative deformation between the TRC strengthening layer and the existing concrete and contributed to improved structural performance.
    Polypropylene fibers had a limited influence on ultimate beam capacity at the tested dosage but contributed to matrix toughness and early crack control.
    The interface agent had only a minor influence on global flexural performance when high-performance fine-grained concrete and adequate substrate roughening were used.
    The steel reinforcement ratio and textile reinforcement ratio should be considered jointly. The effectiveness of TRC is dependent on the interaction between existing steel reinforcement and additional textile tensile resistance.
    The theoretical sectional model provided satisfactory agreement with the experimental results, with the original study reporting errors below 5% for yielding and ultimate load predictions.
    Environmental exposure should be incorporated into future Indian TRC design. Chloride, carbonation, sulfate, moisture, and temperature conditions can influence the long-term performance of strengthened RC infrastructure.
    For Indian applications, textile configuration, bond, anchorage, reinforcement ratio, and environmental exposure should be optimized simultaneously, rather than considering ultimate strength alone.
    TRC therefore represents a promising cement-based strengthening approach for extending the service life of existing RC infrastructure, provided that textile quantity, anchorage, bond, environmental exposure, and failure mechanisms are appropriately considered.
36. Future Research Directions
Future research should develop a larger Indian experimental database covering:
    carbon textiles;
    AR-glass textiles;
    basalt textiles;
    different mesh geometries;
    one to five textile layers;
    different concrete strengths;
    different steel reinforcement ratios;
    different TRC thicknesses;
    different anchorage systems;
    different environmental exposures.
Advanced finite-element simulations should also be developed to reproduce:
"Concrete cracking"→"Steel yielding"→"Textile activation"→"Crack propagation"→"Anchorage response"→"Ultimate failure" 
Machine-learning approaches could subsequently be used to predict ultimate load, crack width, deflection, and optimal textile quantity from experimental and numerical datasets.



Ethical Considerations
Not applicable. This study did not require ethical approval because it does not include human or animal subjects and does not involve any personal or sensitive data.




List of Abbrevations:
reinforced concrete (RC); Textile-reinforced concrete (TRC); C: chloride exposure; H: humidity/moisture variation; T: temperature exposure; S: sulfate exposure; CO_2: carbonation environment; E_f: effective textile elastic modulus; b:beam width;

Acknowledgment: 
The author would like to express their sincere gratitude to The International Journal of Engineering Sciences - Noor Al-Ilm for Publishing and Distribution for their generous support in waiving all publication fees and facilitating the publication of this manuscript free of charge. Their commitment to promoting scientific research and supporting researchers is highly appreciated.


Author Contribution: 
All authors contributed equally to the main contributor to this paper. All authors read and approved the final paper.

Declaration of generative AI and AI-assisted technologies in the writing process
The authors hereby declare that no generative artificial intelligence or AI-assisted technologies were used at any stage during the preparation of this manuscript, including language editing, proofreading, or content development. The authors take full responsibility for the originality and integrity of the work presented in this publication.







Funding: 
This research received no external financial funding. The authors also acknowledge The International Journal of Engineering Sciences, Noor Al-Ilm for Publishing and Distribution, for providing a full waiver of the publication fees. The publication fee waiver was provided as editorial support and did not involve any financial contribution to the conduct, design, analysis, or reporting of the research.


Conflicts of Interest: 
“The authors declare no conflict of interest.”