A Comprehensive Analysis of the Influence of Fly Ash on the Bond Properties between Reinforcing Steel and Concrete

This paper examines the possible use of fly ash to make concrete greener. Because cement manufacturing adds to CO₂ levels, using fly ash instead is becoming more popular. This study seeks to find out how bond strength changes for 0–30% fly ash replacement, study the effects of microstructure, and establish the best ratios for use in structures. For this experiment, we used Grade 53 OPC concrete, which was made to meet a target strength of 20 MPa with a water-binder ratio of 0.5. On-center compressive strength (ASTM C39), tensile strength (ASTM C496), and bond strength (ASTM C900) were tested. The study showed that using a 10% fly ash replacement resulted in the best outcome, raising the concrete’s compressive strength by 7.3% (from 22.3 to 23.6 MPa), tensile strength by 5% (4.2 MPa), and bond strength by 3% (13.9 MPa) by pozzolanic reactions at the interface between aggregates and cement. When the quantity of added fly ash was increased to 20–30%, the concrete became weaker and difficult to work with (slump: 0–0.9 in.), again due to fly ash diluting the binder. We found out that 10% is the most sustainable amount of fly ash for construction. We had used superplasticizers with silica fume when we were going to replace the amount of cement. In the future, experiments with added salt, carbonation, and earthquake loads could extend how widely this approach is used

Effects of Waste Turmeric Oil on the Rheology and Structural Performance of Modified Bitumen

Flexible pavements face continual degradation due to traffic and environmental stresses. Concurrently, waste materials like Waste Turmeric Oil (WTO) pose sustainability challenges. This study explores the WTO as a bio-modifier for VG30 bitumen, aiming to enhance binder performance while addressing waste disposal concerns. WTO-modified binders (WTOMB) were evaluated through physical tests (penetration, softening point, flash point) and rheological tests using a Brookfield viscometer and Dynamic Shear Rheometer (DSR). Results showed that increasing WTO content raised penetration and reduced softening points, indicating improved flexibility. Viscosity decreased by 20–25% at WTO contents above 3%, enhancing workability and reducing mixing temperatures. Short-term aging was simulated using the Rolling Thin Film Oven (RTFO) test, with all samples showing low mass loss and good thermal stability. DSR-based Performance Grade (PG) and Multiple Stress Creep Recovery (MSCR) tests indicated a significant reduction in non-recoverable creep compliance (Jnr) to 1.8 kPa¹ at 3% WTO, identifying it as the optimal dosage for rutting resistance. Although 4% WTO also achieved Jnr 2.0 kPa¹, benefits plateaued. Recovery results suggested that binders with 1–2% WTOMB are suitable for high-traffic conditions. Overall, WTO effectively enhances the performance and sustainability of bitumen binders, offering a cost-efficient and environmentally responsible solution for flexible pavement construction

Prediction of Compressive Strength by Considering Practical Consideration Non-destructive Test by Artificial Neural Network

Accurate assessment of concrete compressive strength is critical for evaluating structural performance. While nondestructive testing (NDT) methods, such as Schmidt rebound hammer tests, offer rapid and NDT gives result with reasonable accurate based on environmental factors such as temperature, humidity etc of site and condition in which test is performed.  Destructive testing (DT) methods, like core cutting, provide direct and accurate results. This study aimed to bridge the gap between these approaches by developing predictive models that correlate DT and NDT results. Experimental work involved 126 laboratory-prepared samples (grades M10–M40) with curing age of 14 day and 28 day and 231 field samples from a 20-year-old structure, tested using both methods. Total 357 no. of data samples were created with different mix proportion of design, curing ages and on-site environmental exposed concrete structure without unknown grade. Most of the researches were done while preparation of samples in the laboratory. For these purposes of taking mixing both variations such as control (Laboratory) and uncontrolled(on-site) samples  were to prepare as a practical condition for prediction. For generation of predict model 70% data was used with methods such as regression analysis and Cascade forward back propagation neural network (CFBPNN) were used for investigation. To validate the prediction 30% data was used which was not used in model generation. The prediction results show that the coefficients of determination (R2) of the Regression analysis and the CFBPNN prediction models for the test set of concrete compressive strength are 95% and 99% respectively ANN model founded to be more accurate as compare to regression analysis. The validation by R2 of the Regression analysis and the CFBPNN prediction model for the compressive strength for above dataset was 89.0% and 98%. Statistical metrics (MSE, RMSE, MAPE) further confirmed the neural network’s superior accuracy

Study on Pipe Strut Dimensions Optimization for Strutted Box Girder Bridge Using FEM

Although the concept of a concrete box girder bridge with strutted wing slabs was proposed long ago as a means to expand the width of bridge sections without significantly increasing the self-weight of the superstructure, research on this structural system remains limited. Using data from a full-scale box girder bridge experiment conducted as part of the Ring Road II Viaduct Project in Vietnam, a finite element model was developed to investigate the influence of the steel struts' geometrical dimensions on the structural behavior of box girders. This paper examines key structural responses, including deflection, stress in the concrete slab, and stress in the steel struts, under varying steel strut dimensions—namely, thickness and diameter. The findings reveal that the diameter and thickness of the steel struts significantly affect beam deflection and strut stress, while their impact on slab stress is negligible. Furthermore, the paper provides practical recommendations for selecting optimal steel strut dimensions and highlights future research directions to enhance the design of such structures. These insights aim to benefit both practicing engineers and researchers in the field

Effect of Waste Plastic and Fiber Modification on Asphalt Mixture Properties

Stone Matrix Asphalt (SMA) and Asphalt Concrete (AC) are widely used in road construction due to their excellent mechanical properties and long-term durability. This study investigates the effect of sisal fiber and waste plastic as modifiers to enhance the performance of SMA and AC mixtures. The Marshall mix design method was employed to determine the optimum bitumen content (OBC) and optimum fiber content (OFC), evaluating parameters such as Marshall stability, flow value, air voids, voids in mineral aggregate (VMA), and voids filled with bitumen (VFB). VG 30 grade bitumen was used as a bitumen, and fly ash was utilized as a filler. Sisal fiber was incorporated to reduce bitumen drain down and improve crack resistance, with the optimal fiber content identified as 0.4% by total mix weight. Simultaneously, waste plastic was added to improve workability and mechanical performance, with 2.5% content enhancing handling characteristics and 3% improving drain-down resistance and tensile strength. Results from drain down and moisture susceptibility tests indicated that the combined use of sisal fiber and waste plastic significantly improved the durability and overall performance of the asphalt mixes

Effects of asphalt binder and aggregate gradation on dynamic modulus, resilient modulus and moisture resistance of asphalt concretes

In this paper, the effects of asphalt binder and aggregate gradation on dynamic modulus (|E*|), resilient modulus (Mr) and moisture resistance of asphalt concretes (AC) have been studied. Six different asphalt concretes are designed with two aggregate gradations (nominal maximum aggregate size of 12.5 and 19 mm) and three types of asphalt binders (penetration grades of 40/50, 60/70 and a polymer-modified bitumen PMB3). Dynamic modulus, resilient modulus and Tensile Strength Ratio (TSR) test have been performed on the studied AC. The |E*| values obtained from dynamic modulus test at various frequencies and temperatures are simulated using a linear viscoelastic model 2S2P1D. Experimental results indicate the clear effect of asphalt binder and aggregate gradation on mechanical properties of tested AC. The 2S2P1D model successfully simulates the |E*| master curve with high precision (R² values from 0.84 to 0.97). The roles of 40/50 and PMB3 asphalt binder in enhancing the performance of asphalt concretes are also clearly demonstrated under each specific temperature condition and mechanical property type

Performance comparison of hyperbolic paraboloidal shell footing with its flat counterpart

While traditional flat footings are commonly used in construction, hyperbolic paraboloidal shell footings present potential benefits in load distribution and settlement reduction. The study encompasses two primary aspects: the design of both footing types in accordance with Indian standard practices, followed by a comparative analysis of their performance utilizing finite element methodology. Performance comparison is carried out concentrating on vertical settlement, stress distribution, and the amount of concrete required under centric gravity loads. The hyperbolic paraboloidal shell footing was modeled with curved surfaces, and the underlying soil was treated as nonlinear using the Mohr-Coulomb yield criteria. The amount of concrete required for a hyperbolic paraboloidal shell footing is significantly less, calculated to be 0.61 times that of a flat footing.

Investigation of permanent deformation characterisation of different asphalt mixtures

Permanent deformation has emerged as a primary distress factor in asphalt pavements, largely driven by the recent rise in tyre pressures and axle loads. This deformation significantly impacts pavement performance, safety, and driving comfort, particularly when rutting depth exceeds a critical threshold. To address this issue, polymer-modified asphalt (PMA) mixtures have been widely adopted as an effective solution to resist permanent deformation (or rutting) under high temperatures. In this study, three different asphalt mixtures—one unmodified and two PMA mixtures—were selected for permanent deformation testing, which included the wheel tracking rutting test and the repeated load axial test under various conditions. The results were then compared, analysed, and discussed. The findings demonstrated a significant improvement in permanent deformation resistance in the PMA mixtures compared to conventional mixtures at both 45°C and 60°C. Furthermore, the results indicated that the use of PMA markedly enhanced both dynamic stability and strain rate, with the improvements becoming more pronounced at higher temperatures

Experimental Evaluation for Improving the Engineering Properties of Concrete Using Partial Replacement of Natural Waste

With the global growth of building construction and infrastructure around the world, the global demand for concrete materials in the construction industry is increasing day by day. Natural waste can be considered an alternative substitute that can be partially mixed into concrete up to a certain limit while maintaining the strength and properties of the concrete for a long duration. In this research, crushed coconut shell as fine and coarse aggregate and coconut shell ash as cement are used as a partial replacement for fine aggregate, coarse aggregate, and cement in concrete. A mix design of M20-grade concrete was prepared as per BIS 1026 2019, and 150 × 150 × 150 mm³ sized cubes of concrete were designed. Concrete materials were replaced with a different form of coconut shells, as cement was replaced with coconut shell ash. In this research, the effects of replacing cement, fine aggregate (FA), and coarse aggregate (CA) were tested in concrete with alternative materials (CSA, CSFA, CSCA) at different levels (0–25%). Concrete strength was measured after 28 days, which represents reduced strength from 24.58 MPa (0%) to 12.80 MPa (25%) in replacing cement with CSA. Increased strength at 5% (28.58 MPa) but dropped to 8.29 MPa at 25% in replacing FA with CSFA. Reduced strength to 8.14 MPa at 25% in replacing CA with CSCA. Replacing all three together lowered strength to 7.25 MPa at 25%. So, only replacements of small proportion (CSFA at 5%) can improve strength, but higher percentages reduce concrete performance. After being prepared, the mould was kept for curing for 3, 7, 14, and 28 days, after which its compressive strength was tested. The result analysis shows that mixing up to 5-10% of crushed coconut shell (CCS) and coconut shell ash (CSA) in concrete does not affect the strength or durability. The limitation of using this natural waste is that it can be substituted up to a certain limit, and the strength graph decreases significantly beyond that limit

Study on Mechanical and Tribological Characterization of Titanium Diboride (TiB2) Reinforced Al7075 Composites by Taguchi Technique

Three distinct titanium diboride (TiB2) weight percentages 3%, 6%, and 9% were incorporated into Al7075-TiB2 composites by stir casting. Al7075-TiB2 composites' wear and mechanical characteristics were evaluated. The microstructural investigation titanium diboride verified the stable interfacial bond between the matrix and reinforcing material as well as the uniform distribution of TiB2 particles. Superior mechanical properties were noted when comparing the 9% TiB2 composites to the 3 and 6% TiB2 composites. The tensile strength was increased by 11.94% for 9% TiB2 reinforced Al composites. Dry sliding wear was measured with pin-on-disc device. Measurements of the samples' wear loss as well as coefficient of friction (COF) showed that the cumulative wear loss for each composite varied linearly with load. As seen by the optical microscope, all specimens within the prescribed tension and sliding distance appear to have oxidative wear on the worn-out surfaces of the wear mechanism. Wear rate is most affected by weight percentage TiB2 (48.43%), followed by load (19.08%), according to the ANOVA. The wt. % of TiB2, at 37.68%, has the biggest effect on the COF, followed by sliding distance (20.54%). Taguchi technique validates the beneficial impact of weight percentage TiB2 on wear loss and COF. The composite reinforced with 9% TiB2 has the finest tribological and mechanical properties