Influence of accelerator type and dosage on the durability of wet-mixed sprayed concrete against external sulfate attack

Autor(es)

Salvador, Renan P. ^{[1, 2]} ; Rambo, Dimas A. S. ^[1] ; Bueno, Roberto M. ^[1] ; Lima, Silvio R. ^[1] ; Figueiredo, Antonio D. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Sao Judas Tadeu, Dept Civil Engn, 546 Taquari St, BR-03166000 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Polytech Sch, Dept Civil Construct Engn, Prof Almeida Prado Ave, Tray 2 83, BR-05424970 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: CONSTRUCTION AND BUILDING MATERIALS; v. 239, APR 10 2020.
• Citações Web of Science: 0

Resumo

External sulfate attack in concrete comprises a series of interdependent processes resulting from the interaction of sulfate ions from the external environment and cement phases, resulting in matrix degradation. To obtain a sulfate-resisting matrix, C(3)A content in cement and water/cement ratio must be controlled. In sprayed concrete, accelerator type and dosage and the interaction between cement and accelerator are important parameters that control sprayed concrete strength and may influence the durability of the matrix. In this context, the objective of this study is to evaluate how accelerator type and dosage influence the durability of sprayed concrete exposed to a sulfate solution. Samples were analyzed by XRD, TGA, SEM, length change, US propagation velocity, compressive strength and water accessible porosity for 270 days. Results showed that sprayed concrete produced with accelerators presents a high deterioration rate due to sulfate attack. Kinetics of specimen expansion and reduction of compressive strength are directly related to the final SO3/Al2O3 ratio of the matrix. This study may be useful to understand how external sulfate attack occurs in sprayed concrete and to develop prediction models and guidelines. (C) 2019 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 17/00125-9 - Caracterização de propriedades químicas, desempenho mecânico e durabilidade de concreto projetado
• Beneficiário: Renan Pícolo Salvador
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado