Equivalent Durability of Concretes Manufactured with a Ground Mineral Addition from MIBA
Silvia Collepardi, Antonio Borsoi, Mario Collepardi, Alessandro Quadrio Curzio
Appears on pages(s):
equivalent concrete durability; ground bottom ash; municipal incinerators bottom ash
A new type of binding material for concrete mixtures has been obtained by physical and chemical treatments of a mineral addition from municipal incinerator bottom ash (MIBA). The treatment process is characterized by a wet micro-grinding of the mineral particles, a full separation of metal scraps from the ground bottom ash, the removal of metallic aluminum particles, and then the absence of hydrogen bubbles development at pH 13 which would occur in the aqueous phase of the fresh concrete during the Portland cement hydration. The final product, in form of a slurry, is partially dried so that a humid aggregate appearing in form of sand is obtained with agglomerated grains of size in the range of 0-6 mm (0-0.24 in.) and with the elemental particles forming the agglomerated grains usually not higher than 12 μm (0.48 μin). The final product has high pozzolanic properties and can be used to produce concrete with improved properties, both in the fresh and hardened states. The new ground mineral addition has been studied to manufacture concrete mixtures from two different points of view: 1) the equivalent strength; 2) the equivalent durability. The present work illustrates the results of research work on the equivalent durability carried out to obtain the certification of a new product through a specific consent of the European Technical Approval (ETA) in order to determine the equivalent strength of the concretes manufactured with a ground bottom ash from MIBA. The assessment of the equivalent durability has been carried out according to the CEN TR 16563 procedure. Besides the compressive strength, the following measurements have been carried out to determine the equivalent durability: water tightness, penetration of carbon dioxide and chloride ions, and exposure to a sulphate aqueous solution.