French Granudem concrete

Wholly recycled concrete product using CDE technology

Poullard SA is an expert in demolition, excavation, roads and networks, based in Lèves, near the city of Chartres in Northern France. Founded in 1979, the company mainly operates in the Eure-et-Loir and Yvelines regions, in the building deconstruction sector. Completing infrastructure demolition projects mainly consisting of concrete, metal or wood, the company also carries out excavation and roadworks.


Leading the movement towards a circular economy in France, in 2015 Poullard embarked on an ambitious project to make concrete from recycled materials. Concerned about the environmental impact of sand mining, it set upon offering a sustainable alternative. The company established the first washed recycled aggregates processing site in the country, Granudem, to recycle concrete blocks and rubble from demolition sites into sand and gravel. Based in Poisvilliers, and founded and run by Alain Poullard, his daughter Aline and his son Stéphane, Granudem’s patented process is unique in France, with resulting aggregates directly re-injected into the concrete manufacturing process at Poullard roadworks sites. The company has since encouraged contractors to choose recycled concrete for their constructions and contribute to the circular economy and the preservation of the environment.


It was during this venture into waste recycling that Poullard first partnered with CDE, leading provider of wet processing solutions. Originally, the company purchased crushing and dry screening equipment, along with a wash plant producing four output sizes. Due to the success that followed, ambitions have grown further. As the company seeks to expand its operations and stride towards new business objectives, including the development of concrete from 100 % recycled aggregates, it has made a significant investment and upgraded its CDE technology.


Larger, more capacity, more outputs

Fed with both recycled concrete and inert soil material, the brand-new wash plant is 5 times larger than the original at Poisvilliers, increasing production capacity to meet the growing demand for recycled materials with ease, and producing a wider range of high-quality recycled materials.


Material is first crushed and pre-screened by the original R4500 primary feeding system and scalping unit to eliminate oversize. From here, it is fed into the new solution which features an AggMaxTM modular logwasher and classifier with patented Infinity screening technology and integrated RotoMax logwasher. Specifically developed and designed for maximum attrition and efficiency on claybound material, high in plastic and sticky contents, the RotoMax also removes contaminants such as wood or plastic by flotation, reinforced by an upward flow.


The high-precision EvoWashTM dewatering and classification system ensures that sand is produced to specification, ready for use straight off the belt, while the ShearCleanTM sand attrition system removes all surface contaminants from the sand and a second EvoWashTM ensures more accurate grading. Finally, the water and sludge processing implemented by CDE allows the recycling of approximately 96 % of the process water required by the system. Two phases lead to transforming the dirty process water into solid filter cake: the AquaCycleTM thickener with flocculation and the filtration of the densified sludge through a filter press.


The hydraulic balance between the logwasher, the sand treatment and the water treatment is one of CDE’s main areas of expertise. CDE’s positioning is qualitative, with the aim of ensuring a unique, durable and sustainable performance and lower operational costs, thus facilitating a quick return on investment.


Promoting a circular economy, together

Using CDE wet processing technology, Poullard is currently washing and transforming waste into high quality, sellable products that can be reused into concrete production for use on local construction sites at a rate of 80tph. The seven outputs, including 0 – 4 mm clean and regular sand, are being used in public works such as local drainage systems and roads, for structural and finishing works, and in paths, pavings and masonry in green spaces.


The company is now selling ready-mix concrete that is made 100 % from recycled aggregates, with CDE technology having helped toward that objective. In addition, Poullard now offers demolition contractors and waste management platforms the opportunity to become franchisees, furthering the reach of Granudem standard concrete.


Stéphane Poullard, Managing Director, explained: “Every year, 40 billion tonnes of sand are extracted from seabeds, mines and lakes to feed the construction industry. By replacing natural sand with recycled sand in our concrete product, Poullard promotes eco-responsibility and contributes to the preservation of the planet. Ready-mix concrete made with recycled aggregates can achieve the same results as that made with virgin quarried materials. Indeed, one of our closest customers has successfully achieved NF certification for the manufacture of concrete blocks using our 100 % recycled sand and aggregates.”


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