Characterization of performable geopolymer mortars for use as repair material

Abstract

Heritage masonry constructions constitute an important percentage of the structures in many countries. These structures are highly vulnerable to environmental changes (such as earthquakes), and significant losses in masonry historical constructions occur even in a moderate earthquake. For this reason, damage assessment studies of these structures before earthquakes are of great importance. After an earthquake, historical buildings in Turkey were examined and it was found that many buildings underwent damage. In these structures, damage occurs during the earthquake due to the use of low‐quality materials and a lack of sufficient connections between the layers. In these buildings, damage especially occurs in the parts that undergo restoration. Since low‐strength repair mortars are generally used in the restored sections, wide cracks have occurred in the building elements under the effect of earthquakes. This study aimed to produce alternative materials that could be used as geopolymer binders in restorated buildings. The mechanical, physical, and microstructural characteristics of the geopolymer samples were investigated in detail using laboratory tests. As a result, the strength of geopolymer repair materials with 8 M and 5% calcium hydroxide (Ca[OH]2) was very high when compared with other values. High‐strength compatible alternative geopolymer repair mortars that could be used for restoration were produced. For this reason, mortar is considered a significant application for repairing and strengthening buildings.

Retraction: Jin, J, Wu, T, Zhang, Z, Fan, J, Lee, X. Application of optimization‐based estimation analysis for predicting the compressive strength of eco‐friendly modified geopolymer concrete. Structural Concrete. 2022. https://doi.org/10.1002/suco.202201051

“…Every year, almost four billion tons of PC are produced, making it the dominant binder in the construction sector [9]. Consequently, it has become essential to create novel binders that use less energy to manufacture and result in lower GHG emissions [10,11].…”

Effect of water‐reducing admixtures water content on rheology, workability, and mechanical properties of fly ash‐based geopolymer and slag‐based alkali‐activated mixtures

“…Researchers used a rotational viscometer and stated that the yield stress of admixture‐free mixture was around 2.05 Pa which reduced to 1.85 and 1.25 Pa upon addition of the melamine‐derived synthetic polymer and modified polycarboxylic ether‐based admixtures, respectively. Maras 32 studied the viscosity of geopolymer repair mortar and stated that the viscosity of these materials was influenced by geometry, size, and volume fraction of particles. Alnahhal et al 27 on the other hand, investigated the effect of Ms ratio and solution/binder ratio on the rheology of fly ash alkali activated pastes with 20% slag replacement, and reported that the yield stresses ranged from approximately 0.10 to 0.70 Pa.…”

Prediction of Geopolymer Concrete Compressive Strength Utilizing Artificial Neural Network and Nondestructive Testing

“…The mechanical investigation included sample testing using UPV and SRH to estimate the GPC compressive strength along with the compression test. The mixing proportions and testing results for collected from Muslum's study are listed in Table 3 [11]. The relationship between the CS of the GPC samples and the above-mentioned test results are presented in Fig.…”

“…The GPC uses pozzolanic materials high in alumina and silica content as a NDTs such as the Ultrasonic Pulse Velocity (UPV) and the Schmidt Rebound Hammer (SRH) to forecast the CS of GPC. These studies reviled that, as in conventional concrete, there are correlations between the GPC CS and both RN and UPV [10,11]. Many NDTs are combined and frequently used empirically, yet, owing to the limited number of existing NDTs, they were seen to be inaccurate.…”