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Self compacting concrete is incorporated with a high amount of fines and chemical admixtures with a low w/c ratio, which leads to shrinkage and microcracks. Shrinkage in the concrete, along with the congested reinforcement, leads to a heavy number of cracks. To stop the damage due to these cracks, the self-healing property was developed in self-compacting concrete by incorporating self-healing materials like bacteria and calcium lactate into it. To optimise the self-healing materials, including the reference mix, 10 mixes are cast and tested for strength and healing properties. In those mixes, both bacteria and lactate are used by 0.2%, 0.4%, 0.5%, 0.6%, 0.8%, 1%, and 1.2% by weight of cement. The compressive strength, UPV, and rebound hammer tests are done on cubes with 100 mm sides. Split tensile strength and self-healing tests are done on cylinders with a 100 mm diameter and a 200 mm height. When a small amount of calcium lactate was used, the compressive strength of the concrete was higher compared to the reference mix. However, increasing the amount of calcium lactate resulted in a decrease in the strength of the concrete. Maximum healing and relatively good strength were found with 0.5% bacteria and 0.5% calcium lactate. FESEM-EDS and XRD results make it clear that the precipitation formed is in the form of rhombohedral calcite.

Introduction: The etiology of nonpuerperal mastitis is more diverse varying from infections to autoimmune disorders. Most of them are misdiagnosed as pyogenic mastitis and are treated with routine antibiotics. In this study the various causes of nonpuerperal mastitis which required surgical intervention were evaluated. It was observed that some of the pre-malignant and malignant conditions were also presented as nonpuerperal mastitis. Materials and methods: All non-lactating women who presented with symptoms and signs of mastitis and did not respond to single course of antibiotics (active against staphylococcus) treated in tertiary care Hospital and in private practice of primary author between June 2021 to December 2022 and in those in whom the ultrasound of breast was also suggestive of inflammatory breast disease were included in the study and rest were excluded from study. The final etiological diagnosis of these patients is given by the histopathological examination of tissue taken from the wall of abscess cavity or of breast mass. Results: Total 21 patients were included in the study of which 7 patients had nonspecific infection, 3 patients were diagnosed to have tuberculous mastitis, 3 patients with idiopathic granulomatous mastitis, 2 patients with periductal mastitis, 1 patient with fat necrosis, 3 patients with atypical ductal hyperplasia and 2 patients were diagnosed to have invasive duct cell carcinoma. Conclusion: The etiology of nonpuerperal mastitis is diverse. Not only the benign conditions but premalignant conditions like ADH, DCIS and even invasive carcinoma can present with clinical symptoms and signs of inflammatory breast disease.

In concrete structures, crack development is a typical phenomenon, it reduces durability and strength. To solve this issue, an autonomous self-healing mechanism was introduced. This mechanism aids in the repair of cracks by generating the calcium carbonate crystals that seal the concrete's pores and micro-cracks. Bacillus subtilis was used in the concrete mix as an additive. In this work, the coarse aggregate was replaced partially by Fly ash aggregates in different proportions. Total eleven concrete mixes are cast and tested for strength properties, in that seven without bacteria and four with bacteria. The crack healing capacity of the concrete specimens was observed at regular intervals by using Elcometer and Digimizer software. The relation between initial crack width and percentage of crack healing was observed. The concrete mix with 30% of fly ash aggregate replacement showed high increment strength in strength of 61.37% and complete healing of maximum cracks width 0.25 mm.

Concrete when exposed to aggressive environmental conditions cause significant damage to the structures which substantially reduces its durability properties. The addition of nanofillers can improve hydration properties and hence improve fresh, hardened, and durability properties. In this study, two types of cements such as Ordinary Portland Cement (OPC) and Portland Pozzolana fly ash-based cement (PPC) were reinforced with Graphene Oxide (GO) to check the chemical resistance towards 5% Sulphuric acid exposure. Initial investigations such as surface characteristics and pore size measurements were analyzed through Brunauer- Emmett- Teller (BET) analysis. The resistance to Sulphuric acid attack is assessed through the change in dimensions, mass, visual observations, un-effected depth by microscopic observations, and loss in flexural strength of acid-exposed specimens. The further obtained reaction products were characterized through Field Emission Scanning Electron Microscopy (FESEM), X-ray Diffraction Analysis (XRD), Fourier Transform Infrared-ray Spectroscopy (FTIR), and Thermogravimetric Analysis (TGA) investigations. The addition of GO improved hydration and formed dense microstructure which enhanced the resistance to acid attack by measuring the change in length, cross-section, and weight loss after the acid attack. 0.04% GO addition improved 24.5% and 1.7% flexural strength after the acid attack. The formation of flower-like crystals by the addition of GO improved better resistance to acid attack confirmed through FESEM morphology. The results obtained showed GO has the potential in improving porosity characteristics by enhancing hydration characteristics. GO helped in enhancing flexural strength and improved microstructure after 28 days of acid exposure in OPC and PPC composites. The overall results showed improved resistance characteristics to Sulphuric acid attack by reinforcing optimum GO content in enhancing hydration and microstructure in OPC and PPC composites.

Bond strength between embedded bar and concrete plays vital role in the design of various reinforced concrete structural elements. Use of metallic and synthetic fibres has been shown to be an effective method to enhance tensile strength, reduce shrinkage and improve durability properties of concrete. However, making of synthetic fibres will not only deplete the natural hydrocarbon resources, but also add greenhouse pollutants to the environment. Hence, sisal fibre was considered as a potential alternative to polypropylene fibre. An experimental study was conducted to evaluate the influence of sisal fibres as mono-fibre and in combination with steel as hybrid fibre on bond strength of concrete. The performance of steel polypropylene fibre reinforced concrete (SPFRC) is compared with that of steel sisal fibre reinforced concrete (SSiFRC). Bond strength was conducted onM30 grade concrete for curing periods of 7, 28 and 90 days. Fibre dosages of 0.50%, 1.00%, 1.25% and 1.50% by volume of concrete were used. Results indicated that increase in steel fibre dosage improved the bond strength slightly. However, increase in fibre dosage of either PP fibres or sisal fibres resulted decrease in bond strength. Furthermore, sisal fibre reinforced concrete (SiFRC) showed inferior performance in bond strength as compared to polypropylene fibre reinforced concrete (PFRC). A detailed statistical analysis revealed that although no strong correlation between the compressive strength and the bond strength was evident from the experimental study, means of bond strength of both the hybrid groups did not differ significantly. In addition, empirical equations were proposed to predict the bond strength of fibre reinforced concrete (FRC) based on compressive strength.

Influence of sisal fibres on impact resistance of structural concrete was investigated and the performance was compared with that of Polypropylene (PP) and Steel fibres. Apart from Mono-fibre reinforced concrete (mono-FRC), resistance of hybrid fibre reinforced concrete (HyFRC) containing steel-Polypropylene (S-PP) and Steel-Sisal (S-Si) fibres to impact loading was also evaluated. Fibre dosages of 0%, 0.50%, 1.00%, 1.25% and 1.50% were used. Drop-weight test in accordance with ACI committee 544 was conducted and compressive strength was evaluated for curing periods of 7, 28 and 90 days. Furthermore, liner regression analysis was performed between the compressive strength and impact resistance. It was found that increase in fibre content improved the impact resistance of FRC. Steel fibre reinforced concrete (SFRC) outperformed and Sisal FRC (SiFRC) showed least performance among mono-FRC. Though S-Si HyFRC performed better as compared to sisal FRC, HyFRC containing S-PP at a fibre dosage 1.5% exhibited superior performance. Keywords: Fibre reinforced concrete, Steel, Polypropylene, Sisal, Impact resistance

Fatigue cracks are a common occurrence in engineering structures subjected to dynamic loading and need to identify at its earliest stage before it leads to catastrophic failure. The presence of fatigue-breathing crack or closing cracks is usually characterised by the presence of sub and super-harmonics in the response of the structure subjected to harmonic excitation. It should be mentioned here that the amplitude of nonlinear harmonics are of very less order in magnitude when compared to linear or excitation component. Further, these nonlinear components often get buried in noise as both are having matched (low) energy levels. The present work attempts to decompose the acceleration time history response using singular spectrum analysis and propose a strategy to extract the nonlinear components from the residual noisy time history component. A new damage index based on these extracted nonlinear features is also proposed for closing crack localization. The effectiveness of the proposed closing crack localization approach is illustrated using detailed numerical studies and validated with lab level experimentation on the simple beam-like structure. It can be concluded from the investigations that the proposed signal decomposition based damage localization technique can detect and locate more than one crack present in the structure.

Risk identification and management are the two most important parts of construction project management. Better risk management can help in determining the future consequences, but identifying possible risk factors has a direct and indirect impact on the risk management process. In this paper, a risk prediction system based on a cross analytical-machine learning model was developed for construction megaprojects. A total of 63 risk factors pertaining to the cost, time, quality, and scope of the megaproject and primary data were collected from industry experts on a five-point Likert scale. The obtained sample was further processed statistically to generate a significantly large set of features to perform K-means clustering based on high-risk factor and allied sub-risk component identification. Descriptive analysis, followed by the synthetic minority over-sampling technique (SMOTE) and the Wilcoxon rank-sum test was performed to retain the most significant features pertaining to cost, time, quality, and scope. Eventually, unlike classical K-means clustering, a genetic-algorithm-based K-means clustering algorithm (GA–K-means) was applied with dual-objective functions to segment high-risk factors and allied sub-risk components. The proposed model identified different high-risk factors and sub-risk factors, which cumulatively can impact overall performance. Thus, identifying these high-risk factors and corresponding sub-risk components can help stakeholders in achieving project success.