Concera admixtures from GCP Applied Technologies create control flow concrete that bridges the gap between conventional and self-compacting concrete. Its labour-saving benefit could prove valuable as Asia’s labour market grows increasingly tight.
“Control flow concrete shows promise in decreasing labour demand and time for concrete placement. It also reduces the risk of segregation,” said Dr Hua Zhong, Asia Pacific’s product director at GCP.
Unlike self-compacting concrete, which is considered costly to produce because it requires a specialised mix design with high powder content and small coarse aggregates, control flow concrete offers many desirable characteristics of conventional and self-compacting concrete without the corresponding negatives, explained GCP.
The company added that like self-compacting mixes, control flow concrete flows and places easily without losing stability, which prevents aggregate segregation. It can be placed with minimal vibration, which helps to cut labour costs. And it does not require extensive quality control to produce, so it eliminates some of the costs that come with self-compacted concrete. It is manufactured using conventional mix designs, with lower powder contents and larger coarse aggregates, further reducing material costs.
“Control flow concrete has distinct rheological behaviour compared to conventional concrete and self-compacting concrete,” said Dr Zhong. “The range of Concera admixtures creates control flow concrete and works with conventional mix designs.”
The image above shows a comparison between conventional mix design with Concera admixtures (first image) and one without Concera admixtures (second image).
GCP also highlighted that, like self-compacting concrete, control flow concrete is higher flowing than conventional concrete, and can be placed into forms with minimal vibration needed, making it an ideal solution for construction slabs and walls, where a smooth surface is vital.
“Adding Concera admixtures to conventional concrete results in highly flowable, segregation resistant concrete that can help improve placement productivity and provide an aesthetically pleasing finish,” added Dr Zhong.
Traditional construction of tunnels, high rises and supporting columns on bridges is labour intensive because conventional concrete needs to be pumped to flow through the heavy steel reinforcement that is required. With control flow concrete, contractors could reduce labour costs since it flows easily and can be easily pumped. With minimal vibrations needed to place the concrete, fewer workers are needed on the jobsite, plus additional cost savings is achieved since vibration equipment is not needed or minimised.
“Concrete quality is related to the mix and the actual installation. With control flow concrete, since it’s highly flowable, it doesn’t require as many skilled workers to move and place the concrete,” said Dr Zhong.
Control flow concrete is also ideal for creating precast concrete beams, columns and underground elements, said GCP, because it is durable and the high flow concrete speeds up placement into forms while reducing the labour and equipment required. The ease of placement also enables precast producers to manufacture more daily, leading to improvements in productivity.
“The global precast construction market is projected to reach US$185 billion by 2022, spurred by increased construction spending and increased urbanisation,” explained Dr Zhong. “With Concera admixtures, precast producers could meet the increasing demand without increasing their investment thanks to the admixtures’ ease of placement and high flowability.”
GCP works with concrete producers and contractors to tailor the right Concera admixture for every project. The company has a network of specialists across Asia with knowledge of local construction methods, materials and building environments, to ensure its customers are able to receive the right product for their project.
According to GCP, the first projects using the new technology have already been completed with favourable feedback. Concera admixtures have been featured in a range of primary applications including horizontal slabs, elevated decks, vertical walls and columns.
For a trial mix of control flow concrete featuring Concera admixture, contact GCP Applied Technologies at: email@example.com