Modern Concrete For 21st Century Construction

Modern Concrete For 21st Century Construction

02nd September 2015

Last week, as a result of some inspiration provided by the exciting new Kingdom Tower project under construction in Jeddah in Saudi Arabia, we took a look at the history of concrete, one of the most versatile materials known to man.  This week, we aim to bring matters more up to date and provide you with some insights into modern concrete.  You will have already read the story of concrete and how it was harnessed by the Ancient Romans which gave them all they need to design and build some of the most fabulous ancient monuments on our planet, so many of which are still standing to this day and have become  must see tourist attractions.  After the fall of the Roman Empire, the knowledge of how to make and use concrete was all but forgotten.

Centuries later, in 1824, Joseph Aspdin developed and patented Portland Cement, the most common type of cement in general use across the world and used as a basic ingredient of concrete, mortar, stucco and most grout.  The main ingredient in Aspdin’s cement is calcium silicate which is formed by heating limestone and silica rich clays in ovens to a temperature of 1,100° Fahrenheit.  This is just what the Campi Flegrei volcano that provided the Romans with their cement had been doing throughout history!

Take a look at this general recipe for Portland clinker (this is the name given to the dried powder version of the cement):

CEMENT

CCN (Cement Chemist’s Notation

MASS %

Calcium Oxide, CaO

C

61 – 67%

Silicon Dioxide, SiO₂

S

19 – 23%

Aluminium Oxide, Al₂O₃

A

2.5 – 6%

Ferric Oxide, Fe₃O₃

F

0 – 6%

Sulphate

1.5 – 4.5%

Proportions can vary depending on the material properties that are required of the cement.

However, concrete is not just cement, it’s all rather more complicated than that.  Modern users of cement have discovered a wide range of useful additives which will allow different types of cement for different applications such as:

  • Road overpasses
  • Dams
  • Reservoirs
  • Runways
  • Buildings
  • Boats

There are all types of concrete additives which can increase electrical conductivity, resistance to acid corrosion, strength and ductility.  Nowadays there are also chemical retardants that can be added to concrete in order to slow hydration, there are accelerators that will speed it up and there are plasticisers that can increase the workability of concrete.  Concrete is becoming more and more versatile as time goes by, nowadays there are pigments that can be added to colour the concrete which is starting a whole new trend of using concrete more indoors as a decorative material. 

Concrete debris was once routinely shipped to landfills for disposal but an increase in environmental awareness is changing all that.  In the spirit of making the construction industry more eco-friendly, concrete recycling is becoming a common method of disposing of concrete structures that are past their sell by date (or being knocked down to make place for newer buildings).

Modern techniques mean that concrete is developing to keep up with the 21st Century and in the coming weeks, we’ll be bringing you more information on some of the most recent developments in the use of concrete, this fascinating and versatile construction material.