Nailing concrete

Abstract

Mix design and concrete production, together with fastener extraction testing were conducted to produce nailing concrete. Nailing concrete is not only meant to be a material that is penetrable using nail fasteners but it must also have enough grip to offer sufficient resistance for a nail to hold firmly and possibly carry load. Different variables were considered resulting in three mix designs containing 8%, 12% and 16% of fine wood-content (less than 4mm in size) initially based on the dissertation work by Adrian Spiteri (2011 ). Apart from the variation of fine wood-content other key variations included two types of nails and time i.e. when the nails were driven in and pulled. Flexural and compression testing were carried out on beam specimens and half beam specimens respectively and gave 28-day flexural strength results ranging from 5.0N/mm2 to 5.5N/mm2 and 28-day compressive strength ranging from 9.3N/mm2 to 21.1 N/mm2. Withdrawal testing on nails was conducted in direct tension using a modified apparatus setup so as to check the nail holding capacity of the wood-concrete. The concrete specimens give more than sufficient resistances of up to G.5kN per nail. A statistical analysis was also carried out to check whether there exists a difference between the two nailed faces i.e. parallel and normal to the plane of casting. This study concludes that nailing concrete is possible using recycled wood aggregate derived from discarded pallets which substitute natural coarse aggregate in fine form.