Abstract
Abstract Among the advances in the use of geopolymer cements is their use as repair materials in concrete structures. The objective of this work was to use a geopolymer cement to repair cracks in concrete specimens, observing its mechanical performance and fracture modes. Cubic test specimens were produced and two types of cracks were evaluated as variables. Cracks were induced by steel sheets during concreting. The geopolymer cement paste and an epoxy adhesive, as reference, were used for the repairs. The results showed a 13% decrease in compressive strength for unrepaired concrete, and 3.7% in concrete repaired with geopolymer. The binder presented mechanical performance similar to that of the epoxy resin regarding crack recovery. In conclusion, repairs made with geopolymer cement are a viable and efficient means of crack recovery.
Highlights
Cracks are common pathological manifestations in concrete structures, which have several causes and modify the aesthetics, while compromising the mechanical properties and durability of the construction
The results showed a 13% decrease in compressive strength for unrepaired concrete, and 3.7% in concrete repaired with geopolymer
When used as crack repair material, epoxy enables the rehabilitation of the concrete mechanical properties [34], a reduction in chloride ion percolation, evaluated by numerical methods [5]; failures can occur at the interface between the concrete and epoxy when subjected to fatigue stress [6]
Summary
Cracks are common pathological manifestations in concrete structures, which have several causes and modify the aesthetics, while compromising the mechanical properties and durability of the construction. Geopolymeric cements are obtained by the chemical reaction between alkali metal and silicate powders, the reaction products are three-dimensional amorphous aluminosilicate networks Their characteristics include high durability [7], low shrinkage [8], good acid resistance [8], good fire resistance [7], low thermal conductivity [9,10] and high temperature resistance [9]. Ueng et al [13] analyzed the adhesion between mortar substrates and activated alkali cements produced with metakaolin, and concluded that by understanding the mechanical models, it is possible to predict the form of rupture and the various stresses that arise in the concrete when geopolymer is used as a structural repair material. A qualitative analysis of the specimen rupture and finite element simulation was proposed to verify the behavior of the materials used and their interfaces
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