Use of treated sludge from cleaning products industry in cementitious matrices

ABSTRACT

The generation of industrial waste has increased continuously encouraging studies about a sustainable and environmentally correct destination to it. As an example, there are the waste generated in cleaning product factories. Aiming to evaluate the incorporation potential of a sludge from an industry of this sector as filler for conventional concretes production, different sludge content was added (5, 10, 15, 20%) in a proportion 1:2:3 (cement:sand:gravel). The mechanical and durability properties of these concretes were evaluated in the fresh and hardened states. All concretes produced with residue showed an increase of workability attributed to the possible presence of surfactants in the composition of effluents. However, compressive strengths lower than the reference concrete were obtained with evidence of an increase in the porosity of the transition zone and greater formation of the compound ettringite in microstructure. For maximum addition content, the reduction in resistance was about 39%. The water absorption and void ratio have slightly increased for all the mixtures, except concrete with 20% sludge. The addition of the residue in the cementitious matrix caused a reduction in durability. As a final evaluation, the maximum addition content recommended is 20%, constituting a significant proportion for waste disposal, however, the produced concretes cannot be used for structural purposes.

Keywords
Concrete; Industrial Sludge; Sustainability