Please share this story:
Please share this story:
In October 2010 CoGri Asia Ltd completed the first ever steel fibre only reinforced concrete (SFRC) slab on piles to be constructed inside China. The project was built for a major UK retailer at their new distribution centre in Jiashan, Zhejiang province, China.
Face Consultants carried out the structural analysis and the design of pile interfaces and jointing details starting in December 2008. CoGri Asia began construction 18 months later. This large 55,600m² building was the Client’s first purpose built facility in the area, and CoGri were awarded this project due to their recent successes on other SFRC projects in Malaysia and Thailand.
Previous experience demonstrated that major efforts of planning would be required to organise materials and construction management personnel. Concrete apart, all materials – reinforcement, jointing systems etc were imported. The multi-national project team was to come from Singapore, UK, Korea, Malaysia and China. A good proportion of these were fluent in Mandarin and English, a key element in working with local labour and suppliers.
The logistics of preparing for this project were difficult. Over 700 tonnes of Arcelor Mittal structural steel fibre and 3.5km of Isedio armour joints were shipped from Europe in a total of 54 containers. Specialist floor laying equipment, laser screed, topping spreader and power finishing tools were shipped in from Singapore.
The three biggest challenges were sourcing a consistent supply of concrete, getting the concrete to the working face of the floor and training and encouraging the local workforce to take an interest in quality control.
The site was about 90 miles from Shanghai and local knowledge and resources for formulating and producing a high performance concrete for 45kg/m3 dosages of metal fibre reinforced concrete were very limited.
Temperatures were in the high 30’s and humidity was also very high. These conditions were difficult for working with concrete of any type, let alone steel fibre reinforced concrete. To cope with fibre integration, delivery and placing times, a working life of 5-6 hours with high workability was required. BASF’s Shanghai laboratory and CoGri’s own UK expert advised on the design mix needed to achieve the high workability and set characteristics required.
A customised PCE admixture was developed that was capable of dealing with the cements and aggregates peculiar to this area. These local materials were very difficult to work with and gave many problems throughout the project. Variable reaction between the cement and admixtures meant that concrete characteristics such as set time, workability and bleed would change dramatically on a regular basis. CoGri adopted a strict testing regime that allowed them to monitor the raw materials on a daily basis and adjust the mix design as required.
The site was almost impassable to truck mixers. Fortunately, a supply of 1.2 x 6 m steel plates was found and these were used by CoGri to pave the access for concrete truck mixers to and from the workface. Co-ordination of the plate movement with Laser Screed, Topping Spreader, Concrete trucks while maintaining the safety of the workforce was a major effort.
The biggest single risk factor was that of delamination which can be hugely costly to a flooring contractor. Unwanted air entrainment from admixture / cement interaction is one of the biggest contributors to air entrainment. To cope with the effects of the variable cement chemistry, it was found to be necessary to adjust defoamer and retarder contents on an almost daily basis so as to minimise the air entrainment to acceptable levels. CoGri found themselves leading the admixture testing and production process at the batching plant.
Despite all these difficulties, the site team pulled together and completed a floor to remember, managing to demobilise from site in October 2010.
People were the key resource in this project. Thanks to the herculean efforts of the project management team; who progressively developed solutions to supply chain problems and completed the project with no ultimate compromising on quality.
Along the way, local labour resources had to be trained and cajoled into taking care with the essential details of concrete floor construction. Maintaining a standard of workmanship proved a challenge due to the transient nature of the workforce, but CoGri’s site team found a way to deliver. Concrete floors are everything about getting the details right: isolation of the slab, joint and load transfer mechanisms as well as interfaces with the client installed flush mount dock pods and delivering a flatness specification completed product.
Please share this story:
For a site visit or advice on the best solution, contact the experts.
“The construction comprised of a concrete slab floor with a..."
Business Development ManagerQueensland drill core facility
"CoGri Middle East LLC (CGME) were appointed to supply &..."
Chief Financial OfficerAl Muqarram Auto Parts Trading, Dubai
"Just to let you know, how pleased I am with..."
Facilities ManagerHomebase
The CoGri Group, a leading international specialist in concrete flooring, with offices throughout the world.
