Abstract

A bridge is a structure built to span physical obstacles such as a waterbody, valley or road to have accessibility for people and vehicles. The design and construction of road bridges require an extensive and thorough knowledge of the science and technology involved with adequate experience of bridge engineering. In India, till now Pre-stressed concrete road bridges are designed and constructed according to Indian road congress guidelines as per IRC: 18-2000 code in which working stress method is adopted. Recently, Indian road congress has introduced another code IRC- 112: 2011 for the design of pre-stress bridges using limit state method. The study of bridge design using the limit state method is discussed to enlighten the recently introduced IRC-112: 2011. The present study has been performed to know the difference in design using IRC-112:2011 and IRC-18:2000 and attempt is made to study undefined parameters of IRC: 112-2011 such as span to depth (L/D) ratio. The present study is based on the design of PSC Box girder by working stress method using IRC- 18-2000 and limit state method using IRC- 112: 2011 code specifications. It is observed that for Box girder, L/D ratios are 33 and 26 respectively for limit state method and working stress method. In Box girder, bridge quantity of concrete can be saved in limit state method. The present study may help in limit state method of Box Girder Bride design for defining L/D ratio.

Abstract

Water is the lifeline of humankind. During the earthquakes their safety and functionality is of major concern. Elevated water tanks consist of huge water mass stored in a tank at the top and is supported by a slender staging system, which is of critical significance contributing towards the failure of the tank during earthquakes. Due to the dynamics of fluid structure interaction, the seismic behavior of elevated water tanks is a complex phenomenon to understand.

In the present study, the seismic performance of intze type of elevated water tanks with various heights of the cylindrical portion for same storage capacity are considered. Seismic analysis is performed considering the elevated water tank as a two degree of freedom system. Different water levels in the tank are studied and the responses such as time periods, sloshing wave heights, base shear and overturning moments are investigated, compared and presented.

Abstract

Avoiding of unsuitable site conditions is not practically possible due to rapid urbanization, so there is a need for soil stabilization. Now-a-days environment is getting polluted by disposal of waste into water bodies without adequate treatment due to which chemical behaviour of water may vary which causes changes in pH of water. This study deals with stabilization of expansive soils using ordinary Portland cement and Portland slag cement separately with different proportions (3%, 5%, 7.5% and 10%) under varying pH conditions (pH=5, pH=7, and pH=9) using UCS and CBR tests. The main objective of this study was to find out the effect of acidic and alkaline nature of curing water on strength characteristics of two different stabilized soils with respect to curing periods (7,14, and 28 days). The test results clearly have shown a significant improvement in strength characteristics of stabilized soils with respect to curing ages.

Abstract

The study is based on the tests carried out on Papercrete to know about its properties. The investigations show that the Papercrete can be used as a very good supplement of wood as it has strengths comparable to wood. Papercrete is an experimental material which replaces an amount of cement with paper in the normal concrete mix. The total weight, cost and CO emissions during its production as compared to the normal concrete are considerably reduced. It has 2 been seen that Papercrete is a lightweight material which is 10 times lighter than the normal concrete with excellent heat and acoustic insulation properties. Weight of 1 mix of Papercrete 60:20:20 was found to be as low as 2600 g in comparison to 26000 g of concrete cube. It has been seen that Papercrete is very workable and can be formed into different shapes such as blocks, panels and sheets with ease. The study has concluded that the dried Papercrete has a rough surface which increases its surface area and provides a very strong bond from one block to the next. There are significant challenges in constructing with Papercrete but also opportunities. Deep knowledge in material properties and long term liability advances in processing and building aspects combined with future material technology can bring Papercrete closer to standardization. This work is based on conducting different experimental tests on various ratios of Papercrete in order to determine its behavior as a building material. The possibilities of its uses in construction have also been determined from the study of these properties.

Abstract

Self-Compacting Concrete (SCC) is a high performance concrete that can flow through every corner in the congested reinforcement sections under its own weight without segregation and bleeding. The SCC is developed by increasing the paste volume and using chemical and mineral admixtures. The fresh and hardened characteristics of SCC are affected by the water available for hydration, humidity and temperature. Curing is adopted to ensure the availability of water for the hydration of cement and this can be done in two ways, i.e., Water adding techniques, and Water-retraining techniques. Self-curing concrete is developed by water retaining technique using various methods. Addition of curing compound to SCC results in self-curing self-compacting concrete (SCSCC). In the present study, the self-curing selfcompacting concrete is developed by using polyethylene glycol as the curing compound and by replacing river sand with quartz sand as fine aggregate. The self curing process is initiated by adding polyethylene glycol to the concrete specimens. To increase in tensile strength, the steel fibers of 1.5% of the cement content are added. The paper addresses the effect polyethylene glycol on fresh and the hardened properties of M60 grade SCSCC. The mechanical properties are presented for 7 and 28 days and are compared with the same grade of SCC with various methods of curing.

Abstract

The utilization of fly-ash in concrete as partial replacement of cement is gaining immense importance today, mainly on account of the improvement in the long term durability of concrete combined with ecological benefits. Technological improvements in thermal power plant operations and fly-ash collection systems have resulted in improving the consistency of fly-ash. The present study was carried out to determine the effect of high volume fly ash on concrete mechanical properties. Different types of concrete mixes were prepared that consist of 40%, 50%, 60% and 70% of class F fly ash by weight of cement which where compared with plain concrete. The mechanical properties of high volume fly ash concrete are evaluated for 7, 28, and 56 days.