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Transportation is pivotal for a nation's economic development and global integration. In India, road transport stands out as a significant mode, requiring effective intercity connectivity. To achieve this, the construction of bridges and culverts is imperative, spanning rivers and nallahs to connect urban centers. Earth-retaining structures are essential for providing crucial support to the approaches of bridges and culverts, effectively preventing material displacement. This study focuses on the investigation of retaining wall structures that are both economically and functionally viable, and commonly employed in bridge construction. The methodology involves the manual design of these retaining wall structures using MS Excel spreadsheets, allowing for a comprehensive comparison to identify the most cost-effective sections and types. The findings suggest that, for greater heights, a box-type return wall proves to be more cost-effective, while a solid return wall is recommended for shorter heights. [ABSTRACT FROM AUTHOR]

Natural contamination is the most pressing issue facing the globe now. As a result of the industrial revolution. There is a massive release of ozone-depleting compounds (such as CO2) into the atmosphere. By increasing the use of modern results, we can reduce the impact of pollution on the environment. There comes a time when "GEO POLYMERS CONCERTE" is the concept. The entire cement content is 100% replaced with Fly ash, Silica flumes, and gypsum are being replaced. For material binding, alkaline liquids such as NaOH and Na2SiO3 are utilized. In our experimental investigation, we utilized low calcium (class F) fly ash obtained from the Thermal Power Plant in Koradi, Nagpur. Alkaline activators used included Sodium Hydroxide in flake form with a 98% purity and Sodium Silicate Solutions consisting of Na2O (14.7%), SiO2 (29.4%), and water (55.9%). We experimented with ratios of 1:1.18:2.58 and 1:1:2, employing concentrations of 8 M and 16 M for NaOH. The focus of this research delved into evaluating the Modulus of Elasticity and Compressive Strength by established standards such as the Australian Standard (3600-2005) and Indian Standard codes. [ABSTRACT FROM AUTHOR]

This paper has reviewed the state of Non-Destructive Testing (NDT) as applied to Civil Engineering in the last decade. This review paper reports on NDTs' application, working principle, configuration, performance, and accuracy. Non-destructive testing (NDT) is also known as non-destructive evaluation (NDE), non-destructive inspection (NDI), and non-destructive testing (NDT). The goal of NDT is to examine a component in a safe, dependable, and cost-effective manner while inflicting no or minimal harm to the equipment and Structure. NDT is important in daily life and is required to ensure safety and dependability. The major use of NDT is to ensure product safety, which has a huge economic value in terms of preventing loss of life and property. It's vital to employ a range of methods. It's critical to comprehend the advantages and disadvantages of any test process. NDT procedures assist uncover hidden flaws such as cavities and water penetration within a building, in addition to providing information on material characteristics. Various NDT techniques such as Rebound Hammer, Visual Inspection, Ultrasonic Pulse Velocity (UPV) Test, Rapid Chloride Permeability Test (RCPT), and Water Permeability Test, are described in this paper. Single NDT may lead to the wrong assessment of concrete structures. Combining various NDT will provide the correct structural health result. By Considering various test results correlation can be identified. [ABSTRACT FROM AUTHOR]

Modern construction is placing an increasing emphasis on the use of materials with superior strength, stiffness, toughness, and durability. Concrete is one of the most utilized construction materials because of its tremendous strength, mounding ability, and durability. Concrete's tensile strength and ductility both are significant disadvantages (toughness). Compaction is required for traditional concrete used in building construction and technical applications to provide strength, durability, and homogeneity. The traditional method of vibratory compaction causes delays and extra costs in projects, as well as posing major health risks owing to noise pollution on and around building sites. Flowable concrete, or SCC, can easily fill formwork and squeeze into small spaces without requiring much segregation or compaction. Recycling is the process of metabolizing waste materials to produce a new, usable good. Waste from building and demolition projects is also used to make recycled aggregate. This kind of recycled aggregate works well in concrete as a dependable replacement for natural aggregate. The use of aggregate from demolished buildings and abraded aggregates from the roadside in structural concrete is a significant step forward. The current research looks at how self-compacting concrete's mechanical strength changes when natural aggregate is partially replaced with recycled material. To obtain sustainable concrete, roadside abraded aggregates are employed as a coarse aggregate partial substitution in concrete. [ABSTRACT FROM AUTHOR]

Concentrating solar power (CSP), when coupled with a supercritical carbon dioxide (sCO2) power cycle and sensible heat storage, presents a renewable and clean alternative for utility-scale power generation. However, in order to be competitive in the current and future markets, CSP facilities must limit their levelized cost of electricity (LCOE) by minimizing capital costs and reducing operating costs over the lifetime of the plant. Targeting this goal, this study investigates the LCOE impact of the power cycle pre-cooler. This study considers a compact dry cooler with micro-channel technology on the CO2 side and formed fin geometry on the air side, using directly-coupled centrifugal fans and a transition duct to improve air distribution across the fins as well as protect the fins from contaminants which may cause blockage, soiling, fouling, and damage. In an effort to better understand the dry cooler impact on LCOE, a sensitivity study was conducted using various combinations of end-to-end approach temperatures, air-side pressure drop values, CO2-side pressure drop values, fan types, cooler turndown control schemes, cooler module sizes, and design-point ambient temperatures. Off-design cycle performance data was calculated for each dry cooler design using NPSS simulation software; cycle performance data were then input to System Advisor Model (SAM) along with the associated capital costs for LCOE prediction of a 100 MW system over a 30 year plant lifetime. Results of this study show the LCOE is most sensitive to air-side performance, followed by heat transfer effectiveness and capital cost. It was found that a power cycle with a mid- to high-performance dry cooler will produce the most competitive power-production costs. Designing at the extreme ends for approach temperature (or effectiveness), design-point ambient temperature, and compactness (footprint) produce higher LCOE values; mid-range values for these parameters balance performance, operating costs, and associated capital cost to optimize LCOE. [ABSTRACT FROM AUTHOR]

In order to maintain viability as a future power-generating technology, concentrating solar power (CSP) must reduce its levelized cost of electricity (LCOE). One component of solving this problem is reducing the cost of the power block while simultaneously increasing the efficiency of the thermodynamic cycle. One disruptive technology that has the promise to accomplish this is supercritical CO2 (sCO2) based power cycles. These cycles are conceptually similar to steam cycles; however, they have substantially smaller turbomachinery at equivalent power while also delivering more efficiency at turbine inlet temperatures of 500-700°C. Previous work has thoroughly investigated the sCO2 turbomachinery design and its impact on power cycle performance and LCOE. However, the precooler (upstream of the first stage compressor) has received significantly less attention. The pr-cooler design is not trivial because minimizing the compressor inlet temperature and temperature variation are critical to cycle performance. Compressor performance and cycle efficiency vary significantly with low-side temperature. Also, operating with a compressor inlet temperature away from the design point (above or below) significantly degrades cycle efficiency. Because CSP plants are generally planned for installation in remote, arid areas where water is scarce, dry cooling is required. The current state-of-the-art dry cooling technology consist of large bays of finned tubes, cooled by fan-driven air in cross flow. The fan-driven air allows for low power consumption and low operating cost. However, the cross-flow configuration results in low thermal effectiveness and maldistribution of air throughout the tube banks. This requires the interface area between streams to be very large, meaning very large installations incurring large capital cost. It has been found that improvements to the dry cooler technology can further reduce the power block contribution to LCOE. This study investigated the impact of the precooler on the LCOE for a CSP facility utilizing a sCO2 recompression Brayton cycle. This paper presents the high-level sensitivity studies used to determine the best path forward for reducing the precooler's contribution to LCOE. The sensitivity study included investigation of the cooler performance (approach temperature), CO2-side pressure drop, air-side pressure drop, air-supply power consumption, and cooler system capital cost. Results of the study show that utilizing a dry cooler with a high effectiveness (achieved at higher heat exchanger capital cost) and low air-side power consumption levels produced the lowest LCOE contribution. Applying more advanced heat exchanger technologies will be required to reach the higher heat transfer effectiveness values, while maintaining reasonable capital cost values. [ABSTRACT FROM AUTHOR]