ADVANCED CONSTRUCTION
CONCRETE
What is concrete?
A blend of aggregates bound together by a hydraulic binder.
→ A combination of particles closely bound together
→ A blend of aggregates, normally natural sand and gravel or crushed rick. Bound
together by a hydraulic binder e.g. Portland Cement activated by water to form a dense
demi homogeneous
- Second most used material after water
- Production of concrete 5% of global CO2 production
- Largest unreinforced concrete building is Pantheon, Rome, 2000 years old
1
, - Een materiaal wordt anisotroop genoemd wanneer zijn eigenschappen niet in
iedere richting dezelfde zijn.
- A joint is a structural element
Concrete was never a single scientific discovery. It developed slowly through a long
process of trial, luck and keen observation.
Before concrete:
➔ Clay: one of the first ancient building materials. The surface, the shallow
lithosphere abundance combined with its workability and cohesive properties;
clay very simple and primitive building material.
➔ 3000 BC: mixed mud with straw to form bricks.
➔ Cement for boatbuilding and Great Wall. Sticky rice as binder in mortar.
Concrete: Historical overview
Concrete floors dating back to 1700 BC were found in Greece
Next major step: introducing lime mortar. Limestone composed of small grains. After
burning it in big ovens, produces quicklime. Then mixed with water = ‘slaking’ = produce
a pasty-like mortar material through a chemical reaction
= Roman lime-mortar
Around 300 BC: the Romans start to build extensively using ‘opus caementicium’
Next step: addition of pozzolana (sandy volcanic ash), it strengthened the mortar and
allowed underwater curing. Pozzolana makes the concrete stronger when the material
cracks. It crystalizes it, and makes it more dynamic by a chemical reaction.
To build Roman Baths, Pantheon, Colosseum,… They used animal fat, milk and blood as
admixtures. They were able to make their own artificial binders.
Concrete wall, not a brick wall, outside brick, inside concrete → Colosseum like this
113 – 125 AD: Pantheon, Rome
2
,The density changed to the top, the more high, the less dense. Because the upper part
needed to carry itself and the under part needed to carry everything on top.
Another secret of the success of the Romans was the use of trade guilds.
Each trade had a guild whose members were responsible for passing their knowledge of
materials, techniques and tools to apprenticeces and to the Roman Legions. In addition
to fighting, the legions were trained to be selfsufficient, so they were also trained in
construction methods and engineering
3
, XI Century: medieval stone masonry with increasing demand for mortar.
3 direct causes led to losing the knowledge of hydraulic cement.
1. Firstly, the poor economic state and lack of funding halted major construction
projects. With lime construction occurring for over a century, the demand of
knowledgeable craftsmen and contractors vastly decreased.
2. Secondly, the barbarian sack of 410 AD caused the few remaining craftsmen and
contractors to flee to the countryside. Once out of the city, these families
continued on substance living in which knowledge of hydraulic concrete quickly
became unwarranted.
3. Lastly, as the Middle Ages progressed, political and economic focus moved away
from Rome and into Northern European ci<es such as London, Paris, and
Cologne. Thus, the natural pozzolanic ash that was vital for the hydraulic cement
was geographically absent.
1756-59 Smeaton’s tower Devon UK: clay-lime cement
After the fall of the Roman Empire in 476 AD, the techniques for making
pozzolan cement were lost until the discovery in 1414 of manuscripts
describing those techniques rekindled interest in building with concrete.
It was not until 1756, when an English civil engineer named John
Smeaton was tasked with the rebuilding of the Eddystone lighthouse that
hydraulic lime cement was rediscovered. Smeaton experimented heavily
on lime with many different admixtures and eventually discovered a
hydraulic lime by combining clay with quicklime. The clay Smeaton used
contained multiple impurities that shared similar chemical compounds
with the pozzolanic ash the Romans used. With this, Smeaton had
developed the first hydraulic cement in over a millennium.
Smeaton’s clay-lime cement opened to the door to the
advancement of modern cement. In 1796, James Parker,
a cement manufacturer, showed that by grinding the
burned lime into powder, the gel making process was
greatly accelerated and improved. The finely powdered
form of quicklime and clay has a large surface area to
volume ration and thus increases the total surface area
in which hydration can more readily take place with the
additions of water. Since then, it has been common
practice to produce cement in a finely powdered form
that can be mixed with water and hydrated on site. By the
way: after 126 years, the Eddystone Lighthouse failed
due to erosion of the rock upon which it stood.
4
CONCRETE
What is concrete?
A blend of aggregates bound together by a hydraulic binder.
→ A combination of particles closely bound together
→ A blend of aggregates, normally natural sand and gravel or crushed rick. Bound
together by a hydraulic binder e.g. Portland Cement activated by water to form a dense
demi homogeneous
- Second most used material after water
- Production of concrete 5% of global CO2 production
- Largest unreinforced concrete building is Pantheon, Rome, 2000 years old
1
, - Een materiaal wordt anisotroop genoemd wanneer zijn eigenschappen niet in
iedere richting dezelfde zijn.
- A joint is a structural element
Concrete was never a single scientific discovery. It developed slowly through a long
process of trial, luck and keen observation.
Before concrete:
➔ Clay: one of the first ancient building materials. The surface, the shallow
lithosphere abundance combined with its workability and cohesive properties;
clay very simple and primitive building material.
➔ 3000 BC: mixed mud with straw to form bricks.
➔ Cement for boatbuilding and Great Wall. Sticky rice as binder in mortar.
Concrete: Historical overview
Concrete floors dating back to 1700 BC were found in Greece
Next major step: introducing lime mortar. Limestone composed of small grains. After
burning it in big ovens, produces quicklime. Then mixed with water = ‘slaking’ = produce
a pasty-like mortar material through a chemical reaction
= Roman lime-mortar
Around 300 BC: the Romans start to build extensively using ‘opus caementicium’
Next step: addition of pozzolana (sandy volcanic ash), it strengthened the mortar and
allowed underwater curing. Pozzolana makes the concrete stronger when the material
cracks. It crystalizes it, and makes it more dynamic by a chemical reaction.
To build Roman Baths, Pantheon, Colosseum,… They used animal fat, milk and blood as
admixtures. They were able to make their own artificial binders.
Concrete wall, not a brick wall, outside brick, inside concrete → Colosseum like this
113 – 125 AD: Pantheon, Rome
2
,The density changed to the top, the more high, the less dense. Because the upper part
needed to carry itself and the under part needed to carry everything on top.
Another secret of the success of the Romans was the use of trade guilds.
Each trade had a guild whose members were responsible for passing their knowledge of
materials, techniques and tools to apprenticeces and to the Roman Legions. In addition
to fighting, the legions were trained to be selfsufficient, so they were also trained in
construction methods and engineering
3
, XI Century: medieval stone masonry with increasing demand for mortar.
3 direct causes led to losing the knowledge of hydraulic cement.
1. Firstly, the poor economic state and lack of funding halted major construction
projects. With lime construction occurring for over a century, the demand of
knowledgeable craftsmen and contractors vastly decreased.
2. Secondly, the barbarian sack of 410 AD caused the few remaining craftsmen and
contractors to flee to the countryside. Once out of the city, these families
continued on substance living in which knowledge of hydraulic concrete quickly
became unwarranted.
3. Lastly, as the Middle Ages progressed, political and economic focus moved away
from Rome and into Northern European ci<es such as London, Paris, and
Cologne. Thus, the natural pozzolanic ash that was vital for the hydraulic cement
was geographically absent.
1756-59 Smeaton’s tower Devon UK: clay-lime cement
After the fall of the Roman Empire in 476 AD, the techniques for making
pozzolan cement were lost until the discovery in 1414 of manuscripts
describing those techniques rekindled interest in building with concrete.
It was not until 1756, when an English civil engineer named John
Smeaton was tasked with the rebuilding of the Eddystone lighthouse that
hydraulic lime cement was rediscovered. Smeaton experimented heavily
on lime with many different admixtures and eventually discovered a
hydraulic lime by combining clay with quicklime. The clay Smeaton used
contained multiple impurities that shared similar chemical compounds
with the pozzolanic ash the Romans used. With this, Smeaton had
developed the first hydraulic cement in over a millennium.
Smeaton’s clay-lime cement opened to the door to the
advancement of modern cement. In 1796, James Parker,
a cement manufacturer, showed that by grinding the
burned lime into powder, the gel making process was
greatly accelerated and improved. The finely powdered
form of quicklime and clay has a large surface area to
volume ration and thus increases the total surface area
in which hydration can more readily take place with the
additions of water. Since then, it has been common
practice to produce cement in a finely powdered form
that can be mixed with water and hydrated on site. By the
way: after 126 years, the Eddystone Lighthouse failed
due to erosion of the rock upon which it stood.
4
