How Concrete is Made
Concrete can be seen almost everywhere in daily life; from roads and bridges, sidewalks, buildings and public parks. As an engineered composite material consisting of filler and binder materials, its presence cannot be overlooked.
Proportioning
Cement, water and aggregates are the key ingredients in concrete mixture. Their proportion must be carefully determined for an effective mixture; its final use determines this.
Portland cement, the most common type of concrete, is made by mixing quarried limestone with silica from industrial byproducts like slag and fly ash to create clinker. Cement plants then grind the clinker to produce fine powder which they blend into water, sand and crushed rock to produce concrete.
Based on your desired application, different chemicals called admixtures may also be added to concrete in order to modify its fluidity (plasticity), speed up setting time or increase strength.
Mixing
Concrete is an exceptionally adaptable material, and can be used to construct skyscrapers, bridges, highways and homes. Furthermore, this remarkable substance can withstand immense strains and compression forces without becoming damaged over time.
Aggregates such as sand and crushed rocks provide the chemically inert foundation of concrete, while the paste composed of cement and water binds these aggregates together.
Mix the mixture until a homogenous mixture results. This makes working with it much simpler, and reduces placement times considerably.
Reducing air pockets that could weaken the final product is key to producing high quality concrete products, and this step can be accomplished using machinery that temporarily liquefies concrete and expels air or by hand tooling.
Concrete house slabs Melbourne typically uses cement paste as its binder; Portland cement is most frequently utilized, though other options such as pozzolans or fly ash may also be suitable. When water is added to the mix, an important chemical reaction known as hydration takes place that begins the forming process.
Hydration
Concrete is made up of rock aggregate bonded together with cement, which is an inert chemical mix. However, unlike sand, gravel, and soil construction materials that simply sit there doing nothing until exposed to moisture (ie sand/gravel/soil), concrete must react with it in order to set.
Hydration is the chemical reaction that begins immediately following proportioning and mixing, continuing during placement, and finally needing to be properly cured to gain adequate strength.
Admixtures are added during the mixing process to alter concrete properties, for instance superplasticizers can increase workability without adding extra water, which makes them useful when handling large volumes.
Placement
Concrete is one of the world’s most commonly used building materials, composed of water, Portland cement and aggregates like gravel or crushed rocks. Concrete can be formed into various structures from foundations to sidewalks.
Concrete must be placed correctly to achieve desired results and this operation plays an essential role in determining the quality of finished structures.
Concrete should be placed as close to its final position as possible and then compacted, steel-troweled and textured as required if skid resistance is desired. Temperature monitoring must also take place during this process to avoid potential environmental conditions impacting its setting process.
Compaction
Concrete mixes consist of three ingredients – water, Portland cement and aggregate – in precise proportions that must be properly calculated in order to create workable and strong concrete mixes.
Once the mixing process has concluded, compaction should take place to ensure a densely packed concrete structure without air voids, which reduce strength.
One way of testing compaction is to insert a poker into the concrete and withdraw it again; when it sinks or leaves an impression when removed from its original place, this signifies the start of compaction and initial setting has begun.
Curing
Concrete cures through hydration, an exothermic chemical reaction between water and its constituent molecules that yields strength, durability and other desirable properties in its final form. Curing is the practice of maintaining ideal temperature and moisture conditions that allow hydration to fully develop its potential.
Curing involves applying methods that prevent loss of mixing water from the surface of concrete, such as ponding or immersion, spraying (or fogging), or covering it with impervious paper, plastic sheeting or membrane-forming compounds.
Curing involves keeping the surface water from evaporating too quickly or else the concrete could develop plastic shrinkage cracks and fissures. Some curing methods also speed up initial setting time and strength gain.