Civil Engineering

In order to increase the strength of subgrade soil and to reduce the construction cost of road and airfield pavement by making best use of the locally available materials, mechanical stabilization technique is one of the vital solution. But, in the past few years, utilization of stone quarry dust has been the focus of few researches. Therefore, in this investigation an attempt is made to stabilize clayey soil using stone quarry dust to analyze the index properties and subgrade strength properties of soil, which includes Atterberg's limits, Compaction Characteristics, California Bearing Ratio and Consolidated Undrained Tri-Axial Compression tests. It was concluded that addition of 30% stone quarry dust had increased maximum dry density, California bearing ratio value, angle of internal friction and decreased the optimum moisture content which made the soil-quarry dust mixes durable.

Nitrate contamination of drinking water has become a massive public health concern since excessive nitrate concentrations are found to cause several health disorders. The present study was undertaken to investigate the nitrate levels in the groundwaters of Bellandur during the pre- and post-monsoon periods of 2017, compare the analysis results with the drinking water standards as per the Bureau of Indian standards (BIS) and assess the potential risk to human health by evaluating by using the Hazard Index (HI) with respect to nitrates. This was achieved by subjecting 30 groundwater samples each, collected from the study area, during the pre and post monsoon seasons. The analysis results reveal that 53.33% of the samples contain nitrate in excess of 45 mg/l, the maximum allowable limits of drinking water laid down by BIS. The hazard index (HI) was evaluated by computing the Chronic Daily Intake (CDI). Results reveal that 14 samples in the post-monsoon and 12 samples in the pre-monsoon have a hazard index greater than unity (1), which indicates a high level of risk due to nitrate exposure in the groundwater endangering the respondents due to excessive nitrate concentrations in the groundwater.

In this study, an experimental investigation on the strength properties of recycled aggregate concrete M40 incorporating copper slag as partial replacement of fine aggregate and micro silica and nano silica as partial replacement of cement has been carried out. For this purpose, eleven concrete mixes were prepared with different replacement ratios of copper slag, micro silica, and nano-silica. Each set of concrete mix comprised of 12 cubes, tested at the age of 3, 7,14 and 28 days of curing period. The physical properties such as grading, specific gravity, and water absorption were determined. According to the results of the experimental study, it is concluded that with complete replacement of natural aggregates with recycled aggregates there was a decrease in the 28 days compressive strength by 23%. However, the best compressive strength was achieved by mix M7 with an increase of 52.93% in 28 days compressive strength compared to the control R.A.C concrete mix C2. Also with the increasing silica content in the concrete, there was a reduction in both the workability and weight density. Therefore, promising results were obtained showing that recycled aggregate concrete can be very well used in place of natural aggregate concrete with the addition of some strength enhancing materials like micro silica and nano-silica.

Dredging of the BONNY OFFSHORE TERMINAL which crosses a bar of 20km long and if dredged will give access to big and modern vessels to enter Port-Harcourt wharf. This study is the analysis of the cost and benefits of carrying out this task. In addition, the problem of selecting a dredger was formulated as a linear programming problem subject to environmental cost and other constraints. Data on the type of equipment, cost, man power needs, environmental friendliness, economy and efficiency were obtained from literature and interviews. The suction dredger was the most suitable dredging machine to work in the area. Other machines such as cutter dredger and grab dredger were found to be expensive and unsafe in areas with a high tidal length. The results are important in decision making on the profitability or otherwise of carrying out similar projects in other areas.

In this paper, an attempt is made to develop an optimization model for design of a steel truss using Genetic Algorithms (GAs) and 2D truss analysis using stiffness method program of NewCivil.com in the MATLAB. The objective function is to minimize the total weight of the truss, subjected to satisfaction of the constraints of axial stresses in the members of the truss and nodal displacements. The 2D truss analysis program is validated with STADD.Pro V8i. The constraints violation is handled by using an adaptive penalty function. GA tool kit functions and the 2D analysis program are combined and implemented in MATLAB. The proposed model is tested on a 3-bar steel tubular truss. After several runs and out of many optimal solutions obtained, the solution with a total weight of 150.15 Kg is considered as the best and the corresponding results are presented.

Many in-fill materials are used to improve ductility of Concrete Filled Steel Tube (CFST). Among the various in-fill materials, fibre is gaining attention in the CFST column. Here an attempt is made to study the effects of the diameter, thickness of steel tube, grade of concrete & volume fractions of glass fibre to Concrete on the behaviour of CFST under Axial Compression. In this research, Taguchi’s methodology with DOE (Design of Experiments) is adopted before conducting experiments for selection of combinations. Therefore, 27 experiments have been conducted for M20 grade, 9 experiments for M25 grade & 9 experiment for Hollow Steel Tube. The results indicate that glass fibre reinforced concrete filled steel tube columns appears to have a significant increasing trend in ductility, & have slight increasing trend in load capacity with increase in volume fraction of glass fibre for 0.5% & 1% whereas decreasing beyond 2%. Obtained Experimental results have been verified with three different codes- Euro code 4, American code (AISC 2005, ACI 2008X, AS), and British code (BS-5400-1979). Variation was found to be in the range of 5%-10% for Euro code & 5%-20% for AISC, ACI, AS & BS-5400 may be due to quality of steel & micro defects.

The present work deals with the results of experimental investigations on effect of sugar powder on setting time and compressive strength of cement and concrete. Effect of sugar on compressive strength of cement and concrete by using different brands of cement are studied. Sugar powder content is 0, 0.05, 0.075, 0.1, 0.15, and 0.2 % by weight of cement. Cube of size 70 mm X 70 mm X 70 mm for compressive strength test of cement. And cube of size 150 mm X 150 mm X 150 mm for compressive strength test of concrete were cast. All the specimens were water cured and testing is done for 3 days, 7 days and 28 days. Results were observe and comparison of results of compressive strength of cement and concrete with sugar powder with that of normal cement and concrete showed the significant improvements in the results of compressive strength.

Water quality monitoring is fast becoming a topic of utmost importance and concern as it deals the health and health issues faced by people. One of the widely employed approaches in water quality assessment is the Nemerow index method and this approach has been employed in the current study and the groundwater quality of K.R.Puram industrial area in Bangalore, India, has been assessed. The quality evaluation has been done by collecting thirty groundwater samples each, both during the pre-monsoon and post-monsoon periods of the year 2017, in and around the K.R.Puram area and subjecting the samples to a comprehensive physico-chemical analysis. To calculate the Nemerow index, ten critical parameters vital from the health point of view has been considered, namely, pH, calcium, magnesium, total hardness, nitrate, chloride, sulphate, total dissolved solids, fluorides and iron. The NPI analysis carried out for these thirty samples revealed that a whopping 93.33 % of the samples exceeded unity, the upper limit for drinking water. The high value of NPI at these stations is mainly due to the excessive concentrations of total dissolved solids, hardness, nitrate, iron, calcium and chlorides. The analysis reveals that most of the groundwater samples are unfit for drinking purposes, which calls for continuous monitoring of groundwater supplies and to adopt a systematic environment management plan to safeguard against the pollution of drinking water.

Previous tests on PVC-concrete composite columns showed that most of tested columns had failure regions near the top or bottom of the columns. Therefore it is intended, in this study, to reinforce the ends of these columns in an attempt to improve their behavior. A series of unreinforced and partially reinforced PVC-concrete composite columns were tested under axial compressive loading. It was found that the strength of partially reinforced PVC-concrete composite column is greater than that of corresponding unreinforced column by about 3%, and that the ultimate strain of partially reinforced PVC-concrete composite column is less than that of corresponding unreinforced column by about 4.4%. Although the increase in strength was unnoticeable, the steel reinforcement at the ends was adequate to prevent failure to occur at these ends.

The present study offers an exploration of the success factor used in green building construction in the Bhopal area. The specific objective includes assessment of the factors relation and its impact. How these factors will play the role and awareness among public as well as in builders of Bhopal region. In total 54 builders is interviewed face to face with the help of semi structured questionnaire. Responses are tabulated and descriptive analysis is performed. Correlation analysis is done for the received data on success factors. It is being found that most of the success factors are related and having impact in the success of green building research.