Paratibha Aggarwal, Associate Professor, Babita Saini, Assistant Professor, Sarvesh Tripathi, M.Tech student, Deptt. of Civil Engg., N.I.T. Kurukshetra

Introduction

Concrete has been the leading building material since it was first used and is bound to maintain its significant role in the upcoming future due to its durability, maintenance free service life, adaptability to any shape and size, wide range of structural properties plus cost effectiveness. The concrete is the most important construction material which is manufactured at the site. It is the composite product obtained by mixing cement, water and an inert matrix of sand and gravel or crushed stone. It undergoes a number of operations such as transportation, placing, compaction and curing. The distinguishing property of concrete is the ability to harden under water. The ingredients can be classified into two groups namely active and inactive. The active group consists of cement and water, whereas the inactive group consists of fine and coarse aggregates. The inactive group is sometimes also called inert matrix. Concrete has high compressive strength but its tensile strength is very low. In situations where tensile stresses are developed the concrete is strengthened by using steel bars or short randomly distributed fibres forming a composite material called reinforced cement concrete (RCC) or fibre reinforced concrete. The resistance of concrete to the slipping of reinforcing bars embedded in concrete is called bond strength. The bond strength is provided by adhesion of hardened cement paste and by the friction between concrete and reinforcement. It is also affected by the shrinkage of concrete relative to steel. On an average bond strength is taken approximately as 10% of the compressive strength. The roughness of the steel surface, water, the chemical composition of cement and steel bar diameter are the factors that affect the bond strength of concrete. In pull-out tests on plain bars, the maximum load generally represents the bond strength that can be developed between the concrete and steel. With plain bars the maximum load is not very different from the load at the first visible slip, but in the case of the deformed bar, the maximum load may correspond to a large slip which may not in fact be obtained in practice before other types of failure occur. The load shall be applied to the reinforcing bar at a rate not greater than 2250 kg/mm, or at no-load speed of the testing machine head of not greater than 1.25 mm/min, depending on the type of testing machine used and the means provided for ascertaining or controlling speeds. The maximum load for each type of failure shall be recorded. The new replaces the old and same follows with the buildings. Older buildings require reconstruction for better and higher economic gains and on account of obsolescence on structural or functional grounds and also due to the damages inflicted on them by natural disasters and wars. The rate of demolition showed an upward trend which in turn increased the dumping costs due to unavailability of appropriate sites nearby. Thus efficient use of the demolished concrete would reduce the costs and definitely lead to conservation of the invaluable non-renewable sources of energy and hence must be given due importance. The demolished concrete could be used as aggregate for concrete resulting in large consumption of the material. Recycling is the act of processing the used material for use in creating new product. The usage of natural aggregate is getting more intense with the development in infrastructure area. In order to reduce the usage of natural aggregate, recycled aggregate can be used as the replacement materials. Recycled aggregate are comprised crushed, graded inorganic particles obtained from the materials that have been used in the constructions and demolition debris. These materials are generally from buildings, roads, bridges, and sometimes even from catastrophes, such as wars and earthquakes.

This section of the article is only available for our subscribers. Please click here to subscribe to a subscription plan to view this part of the article.

Click Here
To Know More or to Contact the Manufacturer
Please let us know your name.
Invalid Input
Please let us know your Designation.
Please let us know your Contact Number.
Please let us know your email address.
Please brief your query.
Our other Value-Added Services:

To receive updates through e-mail on Products, New Technologies & Equipment, please select the Product Category(s) you are interested in and click 'Submit'. This will help you save time plus you will get the best price quotations from many manufacturers, which you can then evaluate and negotiate.

Invalid Input
Invalid Input
Invalid Input
The demand for structural strengthening of ageing structures is growing rapidly in buildings, industrial structures, infrastructure projects like bridges, dams, etc. Structural Strengthening also

Read more ...

Durability and strength are two most important criteria and requirements for the long-term performance of concrete structures against weathering action, chemical attack and abrasion. Any deficiency

Read more ...

Cement is a key binder component of concrete production in the building industry. It is a complex hydraulic binder, made up of four main clinker components; alite (Ca3SiO5), belite (Ca2SiO4)

Read more ...

FAIRMATE manufactures a complete range of construction chemicals and provides cost-effective solutions and world-class services to the Speciality Construction Chemicals Industry in alliance with leading

Read more ...

Corrosion of concrete is a major issue and many concrete structures on adverse environment have experienced unacceptable losses in terms of serviceability, ultimately requiring replacement

Read more ...

Cement is the most used industrial commodity required for development, but it is also responsible for high GHG emissions; so there is a need to create a balance between the nation’s growth and environment sustainability

Read more ...

Cement concrete is the most consumed materials on the earth next only to water. The ingredients used in preparing concrete are not sustainable. The ingredients are responsible for causing global warming. The most

Read more ...

India’s ready-mix concrete (RMC) market is projected to witness a 7-9% CAGR in the next five years. This growth is predominantly driven by the increased investments in the development of infrastructure throughout

Read more ...

Concrete, being a physical mixture of cement, aggregate (sand and crushed rocks), and water, is the key construction material across the world. There is now a huge demand for infrastructure which has increased concrete

Read more ...

There is a need for technologically advanced concrete admixtures for the ready-mix industry that meet industry codes and meet or exceed the demands of challenging construction applications and adverse placement conditions

Read more ...

High Performance Concrete (HPC) is seeing major applications in the field of civil engineering constructions such as long-span bridges, tunnels, high-rise buildings, huge complexes, highway pavements, and more, since

Read more ...

Concrete being the second largest consumed material after water needs attention towards sustainable construction with an increase in infrastructure. The world is moving towards innovative techniques and methodologies

Read more ...

Co-processing of waste in the cement industry is an advanced and innovative recovery process whereby energy is recovered, and the non-combustible part of the waste is reused as raw material.

Read more ...

Traditional masonry units are not sustainable and eco friendly due to consumption of fuel or cement. It is essential to find sustainable alternatives. This paper reports about preparation of geopolymer bricks, masonry

Read more ...

Geo-polymer mortar (GPM) is proven for its strength, durability and sustainability [2 & 3]; strength of GPM is a function of alkaline to binder ratio, and has an adverse effect on consistence properties of mortar

Read more ...

Comparison of Reinforced and Pre-Stressed Concrete Building Frames This article discusses pre-stressing of concrete to get lighter and slender beam sections for six different four storied concrete building frames of different spans/lengths by the application of post-tensioning

Read more ...

Ready mix concrete (RMC) is the first choice for projects requiring concrete. The term ‘ready mix’ is used to describe a process where concrete is pre-made at a plant and delivered in batches to job sites. It is a convenient

Read more ...

When we talk of Primers that are applied before the paint work, what comes to mind are the Acrylic Primers. However, since the last few years, White Cement-based Primers are gaining popularity amongst the construction

Read more ...

Chemistry is truly relevant for concrete because chemistry controls the life/durability of concrete. It explains why cement hardens and the interaction between cement and its environment. Dr. S.B.Hegde at Udaipur Cement Works

Read more ...

Concrete is considered the world’s most versatile, durable and reliable construction material, next only to water. It is the most consumed material requiring large quantity of cement, fine aggregates, course aggregates

Read more ...

×
Sign-up for Free Subscription
'India Construction Week'
Weekly e-Newsletter on Construction Industry
Get the latest news, product launches, projects announced / awarded, government policies, investments, and expert views.