Civil Engineering

Flexible pavement construction in expansive soils is expensive due to large pavement section resulting from low CBR values in wet condition. The volume instability of soil affects constructed pavements and demands frequent maintenance. Hence efforts are to be made for reducing large pavement section and also to suppress swelling of subgrade. Though the use of granular and CNS cushions in pavement construction helps in reducing volume changes affecting pavement layers, it cannot reduce required large pavement sections. Hence, in the present paper, a reinforced flexible pavement design methodology has been formulated for expansive subgrades with the objectives of pavement thickness reduction and swell control of subgrade. Test track studies have been done on unreinforced and reinforced flexible pavement sections laid over selected expansive subgrade. The surface levels have been observed for swell over a period of two years. The proposed design methodology has been validated from the ...

Punica granatum, Citrullus colocynthes, Curcuma long, Albizia lebbeckandAzardirachta indicaare used in traditional medical practice in Sudan for the treatment of gastrointestinal tract infections. The methanol and aqueous extracts from different plant parts (Peel of fruits, rhizome, fruits, leaves, and Gum) respectively at a concentration of 100 mg/ml, were evaluated against 20 clinical isolates (2 were Salmonella typhi,5 Proteus mirabilis,4 Escherichia coli,5 Pseudomonas aeruginosa,3 Staphylococcus aureus, one was Salmonella para typhi B) and 5 standard bacterial strains (Staphylococcusaureus ATCC 25923), Bacillus subtilis (NCTC 8236), Escherichia coli (ATCC 25922), Salmonella typhi (ATCC1319106) and Klebsiella pneumoniae (ATCC 35657) were tested for their antibacterial properties using the Agar Diffusion Technique in vitro. Of all plants methanolic and aqueous extracts of Punica granatum were the most active with clinical isolates and standard bacterial strains showed relatively high antibacterial activity against most of the tested microorganisms with the diameter of inhibition zones ranging between 14 and 24 mm, whereas the methanolic extract of Curcuma long showed high antibacterial activity againstProteus mirabilis clinical isolate (1Z = 20 mm). Most susceptible Gram-negative clinical Isolates bacteria were Escherichia coli and Proteusmirabilis. Most susceptible Gram negative standard bacteria were Bacillus subtilis (NCTC 8236) and Escherichia coli (ATCC 25922) and least susceptible Gram negative bacterium was Klebsiella pneumoniae (ATCC 35657).In Gram positive standard bacteria, most susceptible was S.aureus (ATCC 25923).Antibiotics was used as standards drug for antibacterial assay. The results obtained appeared to confirm the antibacterial potential of the plants investigated, and their usefulness in the treatment of gastrointestinal tract infections.

Flexible pavement construction in expansive soils is expensive due to large pavement section resulting from low CBR values in wet condition. The volume instability of soil affects constructed pavements and demands frequent maintenance. Hence efforts are to be made for reducing large pavement section and also to suppress swelling of subgrade. Though the use of granular and CNS cushions in pavement construction helps in reducing volume changes affecting pavement layers, it cannot reduce required large pavement sections. Hence, in the present paper, a reinforced flexible pavement design methodology has been formulated for expansive subgrades with the objectives of pavement thickness reduction and swell control of subgrade. Test track studies have been done on unreinforced and reinforced flexible pavement sections laid over selected expansive subgrade. The surface levels have been observed for swell over a period of two years. The proposed design methodology has been validated from the ...

This work presents a comparative study on the bearing capacity of strip, square, circular footings and raft foundations in sand, estimated from the standard penetration resistance, N, and the angle of shearing resistance, ϕ. The net safe bearing capacity estimated directly from N using Teng’s equation is compared with that obtained from ϕ as per IS:6403. Likewise, the net safe settlement pressure determined from IS:8009 (Part 1), based on N, is compared with that attained from the semi-empirical approach of Schmertmann et al. A parametric study quantifies the effects of the standard penetration resistance and the size and depth of foundation on the net safe bearing capacity and the net safe settlement pressure of strip, square, circular footings and raft foundations in sand. Interactive charts are prepared in terms of the standard penetration resistance to highlight the appropriate method for the benefit of civil engineers.

Abstract: The flyover constructions have seen a revolutionary change ever since reinforced earth walls have emerged and replaced the conventional retaining walls. The approaches sections of flyovers are now being connected with reinforce earth retaining walls due to fast constructions, low cost and better seismic resistance. The major component of the reinforced earth retaining wall in frictional fill and so cost of the fill influences cost of the wall. The construction cost of reinforced earth walls can be significantly reduced if alternate cost effective materials are used in place of conventional fill material, i.e. sand and gravelly soils. The process of assessing any alternate cost effective material such as a waste, it is essential to have knowledge on requirements of fill for use in reinforced soil structures and methods of evaluation of frictional characteristics of the fill with reinforcing materials. So in the present work besides explaining concept of reinforced earth, re...

At present, rock flour is used as a basement filling material and as alternate to fine aggregate in concrete making. The rock flour of its abundant availability at rock crushing plant and its granular character can be assessed for its usage as better engineering material particularly in reinforced soil constructions by evaluating with reinforcing materials. The grain size, strength and frictional properties of rock flour are to be evaluated for using it as fill material in reinforced soil constructions. In present study, laboratory investigations are carried out to establish the properties of rock flour and then to evaluate its interfacial friction characteristics with geotextiles. Both Modified direct shear test and Pullout test are conducted using rock flour and geotextiles (woven and non-woven) to evaluate interfacial shear parameters in dry and wet condition. The geology of the parent rock is also studied for interfacial shear parameters of strength characteristics of rock flour...

The main objective of Transportation engineering involves safe movement of people and goods on roadways in short time. A number of factors influence the movement of people and goods. The volume, speed and density affect the traffic flow. Traffic volume studies are required as they help in planning, traffic management and predict if any future widening of roads is required. The current work studies traffic characteristics in the city of Visakhapatnam at Andhra University College of Engineering Road connecting Maddilapalem road to Waltair road.. Traffic flow data was collected by manual methods. The traffic patterns during different time periods were analyzed from the data obtained. Hence the results from the present study are helpful in predicting the peak hour traffic, vehicle composition and estimate average daily traffic.