C-DEFENCE™ FOR COASTAL PROTECTION

With an all new concrete mix, designed specifically for underwater abrasion resistance and all weather durability, Macrete C-Defence™ offers greater design life at the same budget. In response to the specification requirements of the Environment Agency, Macrete (Ireland) Limited, a leading precision engineered pre-cast concrete manufacturer, has developed C-Defence™– a microsilica concrete mix with greater strength and abrasion resistance than previously available in the marketplace. Tides, storm surges, and abrasion by water borne solids play a significant role in reducing the design life of the complex and costly sea defence installations taking place around the British coastline and there is an ever pressing requirement to create durable pre-cast concrete components which will withstand future adverse weather, storm and flood cycles for generations to come. In the development of C-Defence™, fifteen different Macrete concrete mixes were trialled against the previously established premium concrete utilised for sea defences – the control mix. As the aggregate used in concrete is a key factor in its abrasion resistance, micro-deval tests were carried out on all aggregates used by Macrete. These tests revealed that a Limestone aggregate had remarkable abrasion resistance, having an almost identical micro-deval coefficient to a granite aggregate used in the control mix. Of course, concrete abrasion resistance is also influenced by other mix parameters including, the shape of the aggregate, the cementitious matrix and its particle density packing. “Wet” concrete abrasion resistance tests to ASTM C1138M (underwater method) were carried out on concrete discs produced from all Macrete trial mixes. The results of these tests indicated that C-Defence™ suffered only half the attrition rate of the control mix. In addition, cube strengths of up to 76N/mm2 were obtained from C-Defence™ , compared with 65N/mm2 from the control mix. C-Defence™ is now being deployed in pre-cast concrete units supplied by Macrete to the Anchorsholme coastal protection scheme which is currently under construction near Cleveleys on the Fylde Peninsular under the supervision of the Environment Agency. C-Defence™ is considered eminently suitable for a range of flood protection precast due to its market leading underwater abrasion resistance, hardness and environmental durability. For further details on C-Defence™ and Macrete (Ireland) Limited’s precision engineered pre-cast capabilities, please contact Iain Hogg, Managing Director on 028 796 50471, or email iain.hogg@macrete.com