Modern spaces demand design flexibility and aesthetics while demanding cutting-edge levels of sustainability. Precast concrete beams and slabs are becoming more popular due to their efficiency, quality control, reduced construction time, and sound and thermal insulation properties.
The construction process for concrete relies on several key steps to ensure quality and durability.
Design and Preparation:
Determine the mix design and select the right proportions of cement, aggregates, water, and additives to achieve the desired properties—clean and set moulds or forms for pouring.
Batching and Mixing:
Measure materials (batching) and mix to create a uniform mixture using drum or pan mixers.
Pouring and Spreading:
Pour concrete into prepared moulds and evenly spread using tools like shovels or rakes to maintain consistent thickness.
Compaction and Vibration:
Remove air pockets and ensure a dense, uniform mix using vibrating tables or handheld vibrators. Proper vibration prevents air pockets and enhances slab quality.
Finishing:
Smooth the surface using trowels or screeds, and apply surface textures if required. Create clean edges and control joints to prevent cracking.
Curing:
Maintaining appropriate moisture and temperature for initial curing allows the concrete to set and strengthen. Final curing methods include water curing, curing compounds, or covering with wet materials to ensure the concrete reaches full strength.
Demolding and Inspection:
Remove the forms after the concrete sets and inspect for defects like cracks or air pockets. Then, perform quality control tests, such as compressive strength tests.
Quality Control:
Ensure compliance with specifications through testing and documentation of the process and any corrective actions to guarantee a durable and high-quality final product.
Fresh concrete usually contains a honeycomb of air pockets, which significantly affects the finished product. Using specially constructed vibrating steel tables, compaction and external vibration are often used to eliminate these from the finished product. These often utilise electromagnets such as REO Type WI21 and are controlled using sophisticated variable controllers like the REOVIB MFS368.
In addition to standards like BS EN123890-2:2019 and ASTM C192, manufacturers implement quality control measures tailored to their specific processes and product requirements. These internal protocols usually involve monitoring vibrating tables to ensure consistent product quality.
A repeatable method for monitoring the vibration and recording any data is essential, and a handheld measurement device like the REO SWM4000 Handheld Vibration monitor can be indispensable.
The SWM4000 reads and can store several instantaneous measurements, such as Frequency [Hz], oscillation amplitude [mm], oscillation speed [cm / s] and oscillation acceleration [g]
As a handheld device with integrated rechargeable batteries, it can be used quickly on-site and in all weather, eliminating the requirement for additional equipment.
The SWM4000 builds on the lessons learned from the design and development of its previous version, the SWM3000. “We learnt quite quickly that the SWM4000 needed to be much tougher than the old version”, Said Steve Hughes, MD of REO UK LTD. “When we designed the product originally, we expected that most units would be used in nice clean laboratories, and the reality could not be further from the truth”, he
continued. “The new unit is much more rugged, with a rubberised case and higher environmental protection. The user interface is much more robust, and the battery life is much longer”.
The SWM4000 interfaces with an accelerometer that can be clamped or attached magnetically to the vibrating table. The data can be stored and exported to a PC for further analysis.
As the drive toward net zero gathers pace, the use of precast products will increase due to their reduced energy and raw material burden. However, as with all concrete products, ensuring quality standards are set and maintained remains essential.
For further information contact: Steve Hughes or Michelle Gillam
REO (UK) Ltd
Telephone: +44 (0)1588 673411
www: www.reo.co.uk
e-mail: marketing@reo.co.uk
