Highway bridges exposed to harsh environmental conditions and located in active seismic regions shows a cumulative increase in earthquake induced damage along their service lives. While environmental degradation mechanisms are typically continuous throughout the lifetime, earthquake shocks are intermittent that depend on the seismicity of the region. Among the different aging mechanisms commonly observed in bridges, this study focuses on corrosion deterioration of critical bridge components such as bridge piers.

In recent decades, particularly after the industrial revolution, the emissions of greenhouse gas (CO2) has substantially increased. The continued increase in the CO2 concentration can lead to an increase in global temperature (see Fig. 1). It is important to note that, the increase in temperature has an effect on the rate of corrosion and consequently, the seismic performance of the bridges may be affected by this variation. In fact, numerous studies have attempted to explain the effects of climate change and global warming on corrosion and maintenance cost of highway bridges.

Civil infrastructure systems such as highway bridges play an essential role in the sustained economic growth and social development of any country. During their service life, highway bridges are continuously exposed to multiple chemical and physical stressors such as corrosion deterioration along with intermittent seismic threats. These deterioration effects, if not effectively monitored and managed, can cause significant reduction in structural functionality and safety especially during extreme event such as earthquakes.

Shear failure is one of the most critical failure modes in reinforced concrete (RC) structures as it is brittle in nature involving the rapid deterioration of strength with increasing widths of the shear cracks. In order to effectively design these structures, it is essential to develop accurate simulation models which can predict their complete nonlinear behaviour. With the development of accurate simulation models, better decisions (retrofitting or demolition) can also be made regarding existing structures during seismic assessments.

Prestressed concrete (PC) members degrade rapidly when the steel strands are subjected to corrosion thereby decreasing the lifespan of the PC structure. Another problem with the use of steel strands is the loss of prestressing force in steel strands which can go up to 24% for prestressed members. Due to this there has been considerable research during the last decade to replace steel strands with Fiber Reinforced Polymer (FRP) strands, which exhibit lower long term losses and are not susceptible to corrosion.

In India, traditional base isolation devices such as rubber pads have been used for more than two decades to reduce the response of structures due to the horizontal components of seismic waves. Such base isolation systems are generally not suitable for providing adequate protection against the vertical components of seismic waves and also result in large relative horizontal displacement between the foundation and the super-structure during seismic events.

The infrastructure of a country plays a major role in its growth and prosperity. It is vital to protect critical infrastructure from natural and man-made hazards to ensure safety of people and minimise environmental and economic impact. One such emerging hazard that requires immediate attention in India is the blast loading of structures due to detonation of high-explosives.

India is looking towards nuclear power as a viable clean energy option to meet its growing energy demands. A target has been set in India’s climate action plan to increase the current capacity of nuclear power from 5 - 63 GW. However, concerns related to seismic safety of nuclear power plants (NPPs) first need to be addressed. One of the possible mitigation measures could be to use seismic isolation to reduce the seismic risk to NPPs.

Geomaterial

The growing population demands a large food production. This leads to generation of a large amount of by-product and waste product. It affects our ecology and climate in an adverse manner. Climate change and the response to it is not new as it is sometimes thought to be. Now a day the generation of bagasse ash from sugar factory is increasing rapidly. Disposal of by-product from industry is major concern as it required vast area. In some places of India, it is used as fertilizer. Use of bagasse ash as fertilizer seems to be a good option of disposal.

India has a very long road network of about 3.93 million km consisting of National highway, State highway, Major district road, other district roads and Village roads. Majority of these roads are with bituminous pavements requiring continuous regular maintenance. In addition to the above, the government has also a very ambitious road development program. All these activities require huge quantities of road construction materials especially stone aggregates. However, the availability of natural resources is limited.

A reinforced wall made by constructing offset at different elevation is called a multi-tiered wall. The disposal of waste such as plastic water bottles and fly ash is a major environmental concern. The study aims at utilizing fly ash as backfill and waste plastic bottle geocell as reinforcement for the wall in a tiered configuration. Laboratory model study and finite element analysis of tiered wall models have been carried out and compared with the single wall.

A cellular mattress used in combination with geomaterials is termeda geocell mattress, a three-dimensional (3D) honeycomb structureconsisting of interconnected multiple cells that can be of differentshapes and sizes. Currently, the cells are generally made of strips ofpolymer sheet or geotextile, geogrid sheets, high density polyethylene(HDPE), or Neoloy polymeric alloy.

In the present study, an attempt has been made to understand the behavior of railway embankment through three-dimensional Plaxis software. The numerical modeling analysis was carried using four different backfill materials such as natural soil, 70% steel slag with 30% soil mixture, fly ash, and expanded polystyrene (EPS) geofoam with three different densities 12, 15 and 20 kg/m3. The comparative investigation of natural soil, steel slag-soil mixture, fly ash, and EPS geofoam as an embankment backfill materials were carried out based on stability and displacement conditions.

Fly ash is nothing but a pozzolanic material formed from thermal power plants during combustion of coals all over the world using crushed coal to generate electricity, which also results in approximately 1 MT (million tons) of annual production of the by-product fly ash that cannot be assimilated to the geo-environment while being disposed and becomes a major threat for environment pollution and land scarcity. Fly ash in bulk quantity has usually been used extensively for the construction of embankments in highways and railways.

Construction of roadway or railway embankments on soft foundation soil such as marine clay is always a major issue due to poor load carrying capacity and excessive settlements. In such conditions, two major remedies are available. One is ground improvement technique by enhancing the engineering properties of foundation soil and second is reduction in the overburden pressure of structure on foundation soil.

Expanded polystyrene (EPS) geofoam is an interesting area in the fields of geotechnical engineering from past four decades. It is rapidly growing and becoming popular due to its large number of applications as a compressible inclusion, lightweight fill and barrier in various structures. An alternative method for compression and tensile testing of EPS geofoam has been proposed which is comparatively easy in terms of fabricating the test assembly and preparation of test specimens than suggested in other test specifications.

In India, steel industry produces 8 million tons (MT) of waste for generation of 25 MT steel annually. An attempt has been made to utilise the steel slag as embankment fill material. Comparative study of embankment modelled with different fill materials such as soil-steel slag mix and natural fill material, using finite element method based software PLAXIS 3D has been carried out. The highway embankment of width 8 meters and 2:1 side slope was modelled using PLAXIS 3D. As the embankment is symmetric with respect to the centre line, only half portion of the embankment was modelled.

Consolidation of soil by surcharge loading with prefabricated vertical drains is an effective ground improvement technique in saturated cohesive soils such as marine clay. Four types of band-shaped drains made from singlelayer woven and non-woven jute geotextile filter fabric wrapped around a core of coir ropes or mats, designated as natural drains, were developed and fabricated. Laboratory marine clay confined discharge capacity and large-scale consolidation tests were conducted on the natural drains and commercially available polymer-based drains.

Nano organosilane for pavement applications