VW Engineering International

In this research work, our emphasis is laid on the employment of rubber tire aggregates( 5% min & 15% max) by partially replacing the coarser rock aggregates in plain cement concrete in the case of rigid pavements. To get the maximum possible outcome it is very much advised to treat the rubber tire aggregate surface with NaOH and cement paste, before using them with M20 concrete mix. Using untreated rubber it was noticed that the overall compressive strength of the concrete mix had a rapid dip but when treated rubber was employed the overall 28-day compressive strength of the mix showed more than a 90% increase, which is quite satisfactory, considering the availability of used tire rubber at ease and cheap rates furthermore its employment reducing the amount of hazardous threat it can pose to the environment. Such an amount of compressive strength is accepted as quite satisfactory for treated rubberized tires, e.g. in the case of floor construction and concrete pavements where the compressive strength is not of so much importance. It was found that the flexural and split tensile strength is higher than the normal concrete but only when the rubber was treated with NaOH and cement paste. However, the workability had a certain dip, flexibility shows awesome increment, and the resultant mix is lighter than the concrete mix because of the light weight of rubber particles. Such enhancement in the properties like compressive strength, split and flexural strength, lightweight, high impact, toughness resistance, etc. can be helpful in the employment of this concrete in various civil engineering works.

Inefficient soil characteristics are a major problem in engineering projects today. Sometimes the first stage in the building is to change the characteristics of inappropriate soil. Early signs of degradation in pavement structures on low soil subgrades include pavement that fails too soon. The potential for clayey soil to exhibit unfavorable engineering features, such as low bearing capacity, high shrinkage, swell characteristics, and high moisture susceptibility, is typically present. It is common practice to stabilize these soils to increase their strength. In order to enhance the engineering performance of soil, a technique called soil stabilization is used to add a binder to the soil. This study details how the addition of both lime and fly ash increased the cohesive soil's strength in the surrounding area. Fly ash has been used to bind non-cohesive soil, granular soil, or soil that is poorly cohesive in place of the typical usage of lime alone in soil that contains clay and is highly cohesive. Fly ash is mostly utilized to support the base course or sub-base.

Soil is the basic foundation for any civil engineering structures and is one of nature’s most abundant construction materials for base. The most important part of a road pavement is subgrade soil and its strength. It is required to bear the loads without failure. If strength of soil is poor, then stabilization is normally needed. Subgrade is sometimes stabilized or replaced with stronger soil material so as to improve the strength. Numerous methods are available in the literature for soil stabilization but sometimes, some of the methods like chemical stabilization, lime stabilization, cement stabilization, fly ash stabilization adversely affect the chemical composition of the soil. In this study bitumen emulsion, cement and lime were mixed with dredged soil to investigate the relative strength of gravel soil in terms of Unconfined Compression Test (UCC), Bearing Capacity and California Bearing Ratio (CBR). The effect of bitumen emulsion, Cement and Lime on the geotechnical characteristics of cement and lime mixtures was investigated by conducting various tests like CBR and UCC. A little cement added to provide better soil strength. It is observed that excellent soil strength results by using cationic bitumen emulsion (CMS) with little quantity of cement used as filler. The appropriate mixing conditions for gravelly soil with CMS Bitumen emulsion have been first attempted. This is followed by deciding four particular material conditions to show the variation in dry density and CBR value to achieve the best possible strength properties of gravel soil. However, in this study, without additives soil was tested to find the Optimum Moisture Content (OMC), CBR value, Plasticity Index and Unconfined Compression Strength.

Due to air pollution and traffic congestion brought on by the fast development in urban travel demand, there is an increasing need for alternate means of transportation in metropolitan areas. By reducing the negative effects of network congestion, a transit system may significantly contribute to improving the sustainability of transportation in these places. A substantial fraction of customers may be persuaded to leave their own vehicles at home and take public transportation instead if the service quality was comparable to that of the automotive mode. By reducing the number of circulating cars and raising the average speed of traffic flow, a competitive transit system can increase user mobility and lower emissions from circulating vehicles. However, the amount of network travel demand that a transportation system captures primarily relies on the level of user service it provides. As a result, it's critical to balance operating costs with service quality by reducing the social, economic, and environmental costs associated with putting in place an effective and sustainable transportation system design.

As more and more renewable energy resources are penetrating the distribution networks, there have been growing concerns regarding its adverse impacts on the integrated power system. Consequently, numerous research works are being focused on methods of mitigating issues such as reliability, low power quality, stability, etc. Here in this paper performance of multilevel inverter for the solar photovoltaic (PV) based standalone and grid-connected system has been enhanced. The inverter circuit has been tested for parameters like THD (Total Harmonics Distortion) and system efficiency for standalone systems having RL load being operated at different power factors. Then the same analysis has been done for a grid-connected system with RL load connected in parallel at PCC (Point of Common Coupling). It is found that THD slightly decreases if the increment is being done in the power factor of the load. These distortions have been then reduced below 5% by connecting passive filters at PCC. Simulation results of THD, power output, and efficiency have been tabulated with variation in the operating power factor of the load. Further, power transfer to the utility grid from the PV inverter is examined along with THD and circuit efficiency. Finally, the simulated results have been plotted and compared with analytical results for validation of the proposed scheme.