Sustainable Concrete Produced with Petroleum Catalyst waste and Polyethylene Glycol as a Self-Healing Agent
Authors: Da Costa Tiago Luiz , Guedes Verenna Santos , Ribeiro Carmen Couto , De Oliveira Danielle Meireles , Henriques Andréia Bicalho , Libânio Marcelo , Ayres Eliane , Almeida Marys Lene Braga 
Published: November 2023

Purpose: To evaluate the production of concrete from the partial replacement of Portland cement with petroleum catalyst residue (RC), generated in large quantities by the petrochemical industries, and the addition of polyethylene glycol 400 (PEG 400), with an emphasis on investigating its mechanical properties and durability, considering the technological, scientific and environmental aspects.
 
Theoretical framework: Oil catalyst waste is generated in significant quantities and is classified as non-inert due to its metal ion content, so there is a need to investigate new disposal methods. The use of RC as partial substitute for Portland cement, with the addition of PEG 400 (self-curing agent), was investigated for the production of non-conventional concrete. The waste has pozzolanic activity, enabling improvements in mechanical properties when added to the cement matrix. PEG 400 has properties that can make concrete more effective in terms of water absorption, hydration heat and workability. The search for sustainability leads to research into new construction materials in order to preserve natural resources and reduce environmental impact. The concrete developed can be lower cost and more durable, without any loss of structural strength.
 
Method/design/approach: The use of RC was investigated with partial substitutions of 2%, 5%, 10% and 20% in relation to the total mass of Portland cement for the manufacture of concrete and the addition of polyethylene glycol (PEG 400) as a self-curing agent. The void ratio, water absorption by capillarity and immersion, specific masses and pozzolanicity index of the waste were investigated. Mechanical and morphological characterization tests were also carried out on the concretes developed.
 
Results and conclution: The compressive strength of concrete produced with 2% RC in relation to the total mass of cement and 1.5% PEG 400 increased by 18.3% compared to conventional concrete. An increase in the amount of residue caused a reduction in concrete strength. The sample with 1.5% PEG 400 obtained better workability in the fresh state, which may be due to the polymer acting as a self-healing agent.  The images obtained by scanning electron microscopy showed that the samples containing 2% added RC had lower porosity. The study showed that the waste can be used satisfactorily in civil construction and the implementation of this new process can reduce global warming and the scarcity of mineral resources, taking sustainability into account.
 
Research implications: This work contributes to a sustainable circular economy with a new process for using petroleum catalyst waste, with pozzolanic characteristics, in cementitious materials.
 
Originality/value: The results will be promising for the use of petroleum catalyst waste and polyethylene glycol in the production of environmentally sustainable concrete.