Term: Ready-mix concrete
History and Growth of Ready-Mix Concrete
– First ready-mix delivery made in Baltimore in 1913
– Over 100 plants operating in the United States by 1929
– Significant industry expansion in the 1960s
– Continued growth since the 1960s
– Dispute over the first factory built
Design and Usage of Ready-Mix Concrete
– Batch plants combine gravel, sand, water, and cement by weight
– Wide range of uses in building, especially in large projects
– Long lifespan compared to other products
– Used when construction site cannot mix concrete on-site
– Cost and time benefits for small to medium projects
– Ready-mix concrete delivered finished, on demand, in specific quantity and mix design
– Cost and time savings compared to on-site mixing
– Environmental concerns with on-site mixing
– Outsourcing concrete production for large projects
– Bought and sold by volume (cubic meters)
Testing, Quality Control, and Advantages of Ready-Mix Concrete
– Ready-mixed concrete specified by weight or volume
– Laboratory testing and field testing for verification
– Admixtures used to modify concrete mix performance
– Limited lifespan between batching/mixing and curing
– Various methods of transportation and placement at the site
– Controlled conditions in ready-mix concrete plants ensure quality
– Use of admixtures and additives to slow hydration process
– Steady supply for large forms to prevent cold joints
– Sophisticated equipment and consistent methods for quality control
– Strict testing of materials and continuous monitoring of key practices
– Improved control over the manufacturing process
– Increased speed in construction practices
– Reduction in cement consumption by 10-12%
– Decreased environmental pollution
– Reduced dependency on human labor
Challenges and Comparison of Ready-Mix Concrete
– Cracking and shrinkage issues
– Weight limitations for access roads and sites
– Need for specialized mini mix trucks in weight-restricted areas
– Limited range of mix designs in centralized batch systems
– Continuous loading and mixing capabilities of volumetric mixers
– Transit Mixed Ready Mix vs. Volumetric Mixed Ready Mix
– Site-mix trucks can serve remote locations
– Volumetric trucks have lower water demand and higher compressive strength
– Centralized batch systems offer a greater range of mix designs
– Volumetric mixers can change mix designs on-site
– Centralized batching provides predictable and consistent results
– Advantages of Centralized Batching
– Tighter tolerances for mixes
– Centralized lab for designing and verifying mixes
– Ability to scale quickly with less movement
– Consistent large-scale pours across a site
– Reduced traffic and fuel consumption for small loads
Additional Information on Ready-Mix Concrete
– Types of concrete
– Reinforced concrete
– References for further reading
– Industry market research and statistics
– Importance of controlling hazardous substances in construction
– Properties of Ready-mix Concrete
– ASTM C 94 and AASHTO M 157 standards govern ready-mix concrete
– Time limit between placing fresh concrete layers is important
– Nano-silica incorporating polymer-modified cement pastes affect the fresh properties of ready-mix concrete
– Chemical admixtures can be used in ready-mix concrete
– Cold joints can occur in ready-mix concrete
– Manufacturing of Ready-mix Concrete
– Fosroc, Akona India, and Major 3000 Concrete Batching are manufacturers of ready-mix concrete
– Precision and quality are important factors in manufacturing ready-mix concrete
– Design and control of concrete mixtures play a crucial role in the manufacturing process
– Structural Properties of Ready-mix Concrete
– Ready-mix concrete is used as a structural material
– Density of concrete affects its weight
– ASTM provides standard test methods for measuring the density of concrete
– The book ‘Structural Materials’ provides insights into the properties of ready-mix concrete
– Ready-mix concrete contributes to the strength and stability of structures
– Applications of Ready-mix Concrete
– Ready-mix concrete is widely used in construction projects
– It is commonly used for building foundations
– Ready-mix concrete is suitable for paving roads and highways
– It is used in the construction of bridges and tunnels
– Ready-mix concrete is also used in the production of precast concrete elements
– Importance of Quality Control in Ready-mix Concrete
– Quality control is crucial in the production of ready-mix concrete
– Adhering to ASTM standards ensures quality control
– Proper testing and monitoring of fresh properties of ready-mix concrete are essential
– Quality control measures prevent issues like cold joints and ensure uniformity
– Ready-mix concrete suppliers should prioritize quality control to meet customer expectations
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Ready-mix concrete (RMC) is concrete that is manufactured in a batch plant, according to each specific job requirement, then delivered to the job site "ready to use".
There are two types with the first being the barrel truck or in–transit mixers. This type of truck delivers concrete in a plastic state to the site. The second is the volumetric concrete mixer. This delivers the ready mix in a dry state and then mixes the concrete on site. However, other sources divide the material into three types: Transit Mix, Central Mix or Shrink Mix concrete.
Ready-mix concrete refers to concrete that is specifically manufactured for customers' construction projects, and supplied to the customer on site as a single product. It is a mixture of Portland or other cements, water and aggregates: sand, gravel, or crushed stone. All aggregates should be of a washed type material with limited amounts of fines or dirt and clay. An admixture is often added to improve workability of the concrete and/or increase setting time of concrete (using retarders) to factor in the time required for the transit mixer to reach the site. The global market size is disputed depending on the source. It was estimated at 650 billion dollars in 2019. However it was estimated at just under 500 billion dollars in 2018.