**8. Summary**

Reinforced concrete is the number one medium of construction. Besides strength, easy formability and availability of the constituent materials, trouble-free long term performance, i.e., durability of concrete structures, constructed with plain round bars of mild steel, having yield stress of around 250 MPa to 280 MPa, had helped reinforced concrete attain this position.

It has been suggested that, in the context of reinforced concrete, besides concrete and rebars, "bond" between such rebars and the surrounding concrete deserves equal consideration.

Engineering practice shows that though there is a need for a clear understanding of "bond", and though the ensurement of adequate "bond" is an essential necessity, these are almost totally neglected.

Similarly, the important property of percent elongation or ductility of the rebar has not been considered with the thoroughness it deserves.

With time, besides significant changes in properties of cement, a constituent component of concrete, the reinforcing bar (rebar) was gradually changed from plain round bars of mild steel to plain round bars of medium tensile steel (yield stress of about 350 MPa) and then on to today's ribbed rebars of high strength (yield stress 415 MPa to about 700 MPa) steel.

The use of ribbed rebars of high strength steel, susceptible to corrosion at accelerated rates, led to concrete structures reaching states of distress early.

In consideration of durability, ribbed bars, as in IS 1786 in India, and ASTM A615/A615M in the USA and as in such other Standards/Specifications elsewhere, should thus be avoided.

The high susceptibility of ribbed rebars to corrosion may in cases destroy or reduce "bond" between concrete and ribbed rebars of high strength steel.

Such bars may not stand scrutiny for eligibility for use as rebars for reinforced concrete construction. It has been shown that PSWC-BAR, characterized by its plain surface and wave-type configuration, is the most ideal rebar for reinforced concrete construction.

While the plain surface of PSWC-BARs would ensure that the susceptibility of such bars to corrosion will be several orders of magnitude less than the susceptibility of conventional ribbed bars of high strength steel, the wave-type configuration of PSWC-BARs ensures that the "bond" or "engagement" between such bars and the surrounding concrete is no less than the "bond" between ribbed rebars and concrete.

Numerous tests on concrete beams and columns, reinforced with PSWC-BARs, and with ribbed bars, conforming to IS 1786, have consistently revealed that the "effective bond" or "engagement" between PSWC-BARs and the surrounding concrete is greater than the "effective bond" between concrete and ribbed rebars, conforming to IS 1786.

It is this greater "effective bond" that increases the load-carrying capacity, ductility and energy absorbing capacity of concrete elements, reinforced with PSWC-BARs.

**35**

**Author details**

Engineering Services International, Salt Lake City, Kolkata, India

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium,

\*Address all correspondence to: dr.anil.kar@gmail.com

provided the original work is properly cited.

Anil K. Kar

*Rebars for Durable Concrete Construction: Points to Ponder*

The use of PSWC-BAR, characterized by its plain surface and wave-type configuration, at no added effort or cost, can solve the worldwide problem of early

forced concrete. It may thus prevent catastrophes during earthquakes.

Besides several-fold enhancement of life span, with many added benefits, like greatly reduced life cycle cost, the use of PSWC-BAR increases by several hundred percent the ductility and energy-absorbing capacity of flexural elements of rein-

Recommended mechanical properties of PSWC-BARs for durable concrete

In consideration of requirements for durability and resistance to earthquake forces, the yield stress of steel in PSWC-BAR is recommended to be limited to

The several-fold enhancement of life span of concrete structures, with the use of PSWC-BARs, instead of conventional ribbed bars, can prevent staggering financial losses to property owners and to national economies of all countries as well as great

An alternative way to enhance the durability of reinforced concrete construction is to provide, at additional cost, surface protection in the form of waterproofing

*DOI: http://dx.doi.org/10.5772/intechopen.95401*

distress in reinforced concrete construction.

constructions are provided.

550 MPa, and preferably to 500 MPa.

treatment to concrete structures.

harm to the environment and to the global climate.

*Rebars for Durable Concrete Construction: Points to Ponder DOI: http://dx.doi.org/10.5772/intechopen.95401*

*Design of Cities and Buildings - Sustainability and Resilience in the Built Environment*

concrete, and it happens best in the case of PSWC-BARs; Kar [2].

had helped reinforced concrete attain this position.

has not been considered with the thoroughness it deserves.

(yield stress 415 MPa to about 700 MPa) steel.

deserves equal consideration.

should thus be avoided.

concrete construction.

conforming to IS 1786.

PSWC-BARs.

these are almost totally neglected.

**8. Summary**

load-deformation plot of the bar beyond yield will provide important information on an idea about the bendability of a rebar. And in addition, the ductility ratio, coupled with a plot of the load-elongation curve of the bar will provide a great deal of information about the performance of a flexural element beyond the yield stress level of the rebar, provided that the rebar will have the requisite "engagement" with

Reinforced concrete is the number one medium of construction. Besides strength, easy formability and availability of the constituent materials, trouble-free long term performance, i.e., durability of concrete structures, constructed with plain round bars of mild steel, having yield stress of around 250 MPa to 280 MPa,

It has been suggested that, in the context of reinforced concrete, besides concrete and rebars, "bond" between such rebars and the surrounding concrete

Engineering practice shows that though there is a need for a clear understanding of "bond", and though the ensurement of adequate "bond" is an essential necessity,

Similarly, the important property of percent elongation or ductility of the rebar

With time, besides significant changes in properties of cement, a constituent component of concrete, the reinforcing bar (rebar) was gradually changed from plain round bars of mild steel to plain round bars of medium tensile steel (yield stress of about 350 MPa) and then on to today's ribbed rebars of high strength

The use of ribbed rebars of high strength steel, susceptible to corrosion at accelerated rates, led to concrete structures reaching states of distress early.

In consideration of durability, ribbed bars, as in IS 1786 in India, and ASTM A615/A615M in the USA and as in such other Standards/Specifications elsewhere,

The high susceptibility of ribbed rebars to corrosion may in cases destroy or

Such bars may not stand scrutiny for eligibility for use as rebars for reinforced concrete construction. It has been shown that PSWC-BAR, characterized by its plain surface and wave-type configuration, is the most ideal rebar for reinforced

While the plain surface of PSWC-BARs would ensure that the susceptibility of such bars to corrosion will be several orders of magnitude less than the susceptibility of conventional ribbed bars of high strength steel, the wave-type configuration of PSWC-BARs ensures that the "bond" or "engagement" between such bars and the surrounding concrete is no less than the "bond" between ribbed rebars and

Numerous tests on concrete beams and columns, reinforced with PSWC-BARs, and with ribbed bars, conforming to IS 1786, have consistently revealed that the "effective bond" or "engagement" between PSWC-BARs and the surrounding concrete is greater than the "effective bond" between concrete and ribbed rebars,

It is this greater "effective bond" that increases the load-carrying capacity, ductility and energy absorbing capacity of concrete elements, reinforced with

reduce "bond" between concrete and ribbed rebars of high strength steel.

**34**

concrete.

The use of PSWC-BAR, characterized by its plain surface and wave-type configuration, at no added effort or cost, can solve the worldwide problem of early distress in reinforced concrete construction.

Besides several-fold enhancement of life span, with many added benefits, like greatly reduced life cycle cost, the use of PSWC-BAR increases by several hundred percent the ductility and energy-absorbing capacity of flexural elements of reinforced concrete. It may thus prevent catastrophes during earthquakes.

Recommended mechanical properties of PSWC-BARs for durable concrete constructions are provided.

In consideration of requirements for durability and resistance to earthquake forces, the yield stress of steel in PSWC-BAR is recommended to be limited to 550 MPa, and preferably to 500 MPa.

The several-fold enhancement of life span of concrete structures, with the use of PSWC-BARs, instead of conventional ribbed bars, can prevent staggering financial losses to property owners and to national economies of all countries as well as great harm to the environment and to the global climate.

An alternative way to enhance the durability of reinforced concrete construction is to provide, at additional cost, surface protection in the form of waterproofing treatment to concrete structures.
