Some Stuff the World is Made Of

In terms of its basic composition, concrete is a mixture of roughly 10% cement, 20% air and water, 30% sand, and 40% gravel. In construction, this is the so-called 10-20-30-40 rule, although the proportion varies depending on the type of cement needed and other factors.

Putanother way, it is the man-made composite material, comprising a matrix of cementitious binder (typically Portland cement) and a dispersed phase or “filler” of aggregates (typically a rocky material, loose stones, and sand).

For some, concrete is being regarded as the foundation of modern civilization since it is the composition of most ofthe structures the modern world is made of: buildings, bridges, roads, factories, houses, office buildings, etc.

Obvious advantages 

The unyielding nature of concrete makes it a durable, long-lasting building material choice. It resists erosion, fire, rotting, rusting, and weathering with relative ease, requiring minimal maintenance and repair. 

Concrete has proven that its lifespanexceeds many other types of building materials.

Among its many advantages, durability stands out as its most important qualities. Most concrete buildings are designed to last at least 30 years in service. However, many last longer before deteriorating to the point of repair or replacement.

Concrete is mostly preferred due to its being fire resistant, lower costs, construction speed, energy efficiency, versatility and low maintenance.

Building medium

As it is, concrete is the world’s most widely used architectural medium, owing to its incredible versatility. As a building material, it has a unique ability to be shaped and sculpted into anything from roads and footpaths to art sculptures, residential homes and skyscrapers.

There are no limits to where and how concrete can be used and its inherent strength and durability underscores its credentials as one of the most sustainable building products.

Concrete is the most cost-effective construction material for many applications. It is the most consumed substance in the world (after water).To date, 70% of the world’s population lives in a structure that contains concrete.

Concrete types

Concrete is used in many different kinds of construction projects because it is affordable, durable, and can be molded into nearly any shape. It is a building material made by mixing cement, aggregates, and water in precise proportions.

After all the years, concrete has evolved into more or less five types, mostly dependent n its use in any construction project.

Reinforced concrete

This concrete type is reinforced with the use of steel bars (or mesh made out of steel) to increase its tensile strength and durability. It is commonly used in the construction of high-rise buildings, bridges, and other structures that require extra strength and stability.

Lightweight / high-strength / high performance  

As the name suggests, this type of concrete is lighter in weight than normal concrete, making it ideal for construction projects where weight is a concern. It is commonly used in the construction of precast concrete elements, such as wall panels, roof slabs, and paving blocks.

This high-strength type of concrete has a compressive strength of over 40 MPa and is used in the construction of structures that require extra strength, such as tall buildings, bridges, and dams.

The high-performance concrete is a specialized type of concrete that has enhanced properties, such as high durability, increased strength, and resistance to extreme temperatures and environmental conditions. 

It is commonly used in the construction of nuclear power plants, offshore structures, and other high-tech projects.

Precast concrete

This type of concrete is manufactured off-site and is then transported to the construction site. It is commonly used in the construction of precast concrete elements, such as wall panels, columns, beams, and staircases. 

Precast concrete offers several advantages over traditional cast-in-place concrete, including reduced construction time and increased quality control.

Composition

The water is used to hydrate the cement and activate the chemical process that hardens the concrete. This is why the ratio of cement to water is an essential factor in determining the strength and durability of the concrete. 

The ideal water cement ratio needs to first be calculated because, higher water-to-cement ratio can result in weaker, less durable concrete that is more prone to cracking and erosion.

Water and cement initially form a cement paste that begins to react and harden (set). This paste binds the aggregate particles through the chemical process of hydration. 

In the hydration of cement, chemical changes occur slowly, eventually creating new crystalline products, heat evolution, and other measurable signs.

In addition to the three main ingredients, concrete may also contain additives such as admixtures, which can enhance certain properties such as workability, strength, and durability. These additives can include fly ash, silica fume, and plasticizers, among others.

The concrete’s properties makes it an ideal building material for a wide range of applications. Here are some of the most important properties of concrete.

Workability / strength

This is the ease with which the concrete can be mixed, transported, and placed into its final position. A high degree of workability is essential for achieving the desired shape and finish of the concrete.

Concrete has proven its strength and can withstand heavy loads and stresses. The compressive strength of concrete can vary widely depending on its composition and curing time.

Durability/creep

Concrete is well-known to be highly durable and can withstand exposure to elements, including water, wind, and extreme temperatures. Proper curing and maintenance can extend the lifespan of concrete structures.

Creep is the term that refers to the gradual deformation of concrete under sustained loads over time. Creep can result in structural damage if not accounted for during the design and construction process.

Shrinkage/unit weight

Concrete can shrink as it dries, which can result in cracking and other damage. Proper reinforcement and curing can help minimize the effects of this shrinkage.

In another context, the unit weight of concrete refers to its density and can vary depending on its composition and strength. A higher unit weight can result in stronger and more durable concrete.

Modular ratio/Poisson’s ratio

Modular ratio refers to the relationship between the elastic moduli of concrete and the steel reinforcement used to reinforce it. A higher modular ratio can result in stronger, more durable structures.

On the other hand, Poisson’s ratio is a measure of the ratio of lateral strain to axial strain when a material is stretched or compressed. This ratio can affect the overall strength and stability of concrete structures.

Concrete is a versatile and durable building material that has been used for centuries. Understanding what it is made of, the types, its composition, and its properties are all 

essential for achieving the desired strength, durability, and performance of the finished product.