Ready Mix Concrete

Ready Mix Concrete

Concrete is a composite consisting of the following main constituents: cement, aggregates, water, and admixtures.

It is a material that can be cast into different shapes, is durable, is the most attractive construction material in terms of compressive strength (construction material with highest strength per unit cost), and its increasing use is fundamental for sustainable construction.

Sustainable Benefits of Ready-Mix Concrete

• We continuously work to improve the properties of concrete that make it a key component of sustainable construction: durability, resistance to aggressive environments, light reflection, and capacity to store energy, among others.
• We also constantly work to develop innovative solutions that advance the sustainability of structures made with concrete. In this way, our customers can design sustainable buildings that can take advantage of the benefits of concrete in a wide range of applications.

Engineered Concrete

• A special design of high performance concrete combines durability and low maintenance with resistance to aggressive environments.
• Industrial Applications: concrete with high acid resistance is robust and durable for such uses as cooling towers.

Building and Housing

• Structures: self-compacting concrete improves strength and durability of building structures, while reducing energy use and noise due to concrete vibration.
• Envelope: structural lightweight concrete or Insulating Concrete Forms offer insulation solutions to improve energy efficiency in buildings.
• Building Design: concrete’s capacity to store energy—its thermal mass—minimizes temperature fluctuations in a building over the course of the day, reducing the need for additional heating and cooling.

Water and Wastewater Management

• Pervious Pavement: pervious concrete allows rainwater to filter through and reduce flooding, while helping to decrease heat concentration.
• Water Channels: concrete water channels are used in farming to reduce the amount of water lost as it flows through fields. Locally produced concrete also provides an affordable solution.
• Potable Water and Sewage Systems: high performance concrete is used for pipes, which are affordable, long-lasting, have high structural strength, and can withstand water abrasion.
• Wastewater Treatment Plants: special cements and high technology concrete design increase chemical resistance and reducing maintenance.

Roads and Pavements

Paving: Concrete roads are durable and need little maintenance. They require less energy for street lighting, keep urban areas cooler, and decrease the urban heat island effect.

Concrete Ingredients

Concrete Ingredients

The basic ingredients in concrete are cement, aggregates, and water. The type, quality, and proportioning of these ingredients affect the curing rate, compressive strength, and durability of the concrete. Chemical admixtures can be used to enhance one or more properties of the concrete or to improve its handling and placing characteristics.

Cement

Cement is not the same thing as concrete. Many people mistakenly refer to “cement” sidewalks or “cement” driveways and the like, but cement is only one of the ingredients in concrete. It is also an ingredient in masonry mortar, stucco, and other materials.

• Cement + water = cement paste
• Cement + water + sand =cement mortar
• Cement + water + sand + lime = masonry mortar
• Cement + water + sand + coarse aggregate = concrete

Aggregates

The aggregates most commonly used in concrete are sand, gravel, crushed stone, crushed slag, and pumice. Cement and water are mixed with aggregates to produce concrete. Concrete contains both fine and coarse aggregates. When cement is mixed only with fine aggregate, it is called cement mortar, which is used typically for patching and small repairs, or for coating a concrete surface to provide a smooth, even finish. Masonry mortar is different from a simple cement mortar because it contains other ingredients as well.

Water

As a rule of thumb, water used for mixing concrete should be drinkable. Any water that is drinkable is generally free of harmful impurities. In urban areas where municipal water supplies are available, contaminated water is usually not a problem.

Admixtures

Admixtures are substances other than cement, water, or aggregates which are added to concrete mixes for the purpose of altering properties of the fresh or hardened concrete. Admixtures are not generally required to produce high quality, low cost concrete, but they may sometimes be necessary or desirable to alter specific properties of the concrete for specific conditions or circumstances.

Chemical Admixtures

Set accelerators speed up the setting time and early strength development of concrete. This can be helpful in winter weather to reduce the length of time required for curing and protection and to compensate for the effects of low temperatures on strength development.

Need to be Specified for Ready Mix Concrete

Need to be Specified for Ready Mix Concrete

The following need to be specified very clearly:

• Characteristic strength or grade (N/mm2)
• Target workability or slump in mm required at site
• Exposure conditions for durability requirements
  • Maximum water to cement ratio
  • Minimum cement content
  • Maximum aggregate size
  • Type of cement
  • Mineral admixture and its proportion (Kg/m3)
• Maximum aggregate size
• Rate of gain of strength (for formwork removal or prestressing etc.)
• Maximum temperature of concrete at the time of placing (in extreme climatic conditions or incase of massive concrete pours)
• Type of surface finish desired
• Method of placing
• Rate of supply desired to match the placing and compaction speed planned at site.
• Quantity of concrete required.
• Lift and lead of concrete transportation and placement at site.
• Frequency of concrete testing
• Details of materials and their required tests.
• Permeability tests required (if any)
• Placing of concrete in formwork to be under scope of RMC supplier (if required)
• Permissible wastage
• Mode of measurement.

 

Ready Mix Concrete

Ready Mix Concrete

Ready Mix Concrete is a specialized material in which the cement aggregates and other ingredients are weigh-batched at a plant in a central mixer or truck mixer, before delivery to the construction site in a condition ready for placing by the builder. Thus, `fresh’ concrete is manufactured in a plant away from the construction site and transported within the requisite journey time. The RMC supplier  provides two services, firstly one of processing the materials for making fresh concrete and secondly, of transporting a product within a short time.

 Sometimes Materials such as water and some varieties of admixtures can be transit-mixed (also known as Transit Mixture), that is they can be added to the concrete at the jobsite after it has been batched to ensure that the specified properties are attained before placement. Here materials are batched at a central plant and are completely mixed in the Batching Plant or partially mixed intransit. Transit-mixing keeps the water separate from the cement and aggregates and allows the concrete to be mixed immediately before placement at the construction site (Dry Concrete). This method avoids the problems of premature hardening and slump loss that result from potential delays in transportation or placement of central-mixed concrete.

 Additionally, transit-mixing allows concrete to be hauled to construction sites further away from the plant. There are several types of RMC plants varying in type of mixing and capacity of concrete production.