Laboratory evaluations were performed to investigate the effect of internal curing (IC) by superabsorbent polymers (SAP) on the internal relative humidity (IRH), autogenous shrinkage, coefficient of thermal expansion (CTE), and strength characteristics of low water-cement ratio (/) mortars. Four types of SAP with different cross-linking densities and particle sizes were used. Test results showed that the SAP inclusion effectively mitigated the IRH drops due to self-desiccation and corresponding autogenous shrinkage, and the IC effectiveness tended to increase with an increased SAP dosage. The greater the cross-linking density and particle size of SAP, the less the IRH drop and autogenous shrinkage. The trend of autogenous shrinkage developments was in good agreement with that of IRH changes, with nearly linear relationships between them. Both immediate deformation (ID)-based and full response-based CTEs were rarely affected by SAP inclusions. There were no substantial losses in compressive and flexural strengths of SAP-modified mortar compared to reference plain mortar. The findings revealed that SAPs can be effectively used to reduce the shrinkage cracking potential of low / cement-based materials at early ages, without compromising mechanical and thermal characteristics.
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http://dx.doi.org/10.3390/polym10101074 | DOI Listing |
Sensors (Basel)
December 2024
Graduate Program in Electrical Engineering, Federal University of Espírito Santo, Vitória 29075-910, ES, Brazil.
Smart concrete is a structural element that can combine both sensing and structural capabilities. In addition, smart concrete can monitor the curing of concrete, positively impacting design and construction approaches. In concrete, if the curing process is not well developed, the structural element may develop cracks in this early stage due to shrinkage, decreasing structural mechanical strength.
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
Key Lab of Smart Prevention and Mitigation of Civil Engineering Disasters of the Ministry of Industry and Information Technology and Key Lab of Structures Dynamic Behavior and Control of the Ministry of Education, Harbin Institute of Technology, Harbin 150090, China; School of Civil Engineering, Harbin Institute of Technology, Harbin 150090, China. Electronic address:
To address the challenge of adaptability between cement-based materials and conventional superabsorbent polymers (sodium polyacrylate, Na-PA), a chitosan-based superabsorbent polymer (CSP) with high salt and alkaline resistance was synthesized, and the optimal synthesis process was determined by a single-factor method. The macroscopic performance and microstructure of CSP and Na-PA were compared, and their influences on cement paste were studied. The results show that CSP exhibits a gradual swelling process during water absorption, which is independent of the solution environment.
View Article and Find Full Text PDFMaterials (Basel)
September 2024
Považská Cementáreň Cement Plant (PCLA), 01863 Ladce, Slovakia.
Hybrid cements combine clinker with large amount of supplementary cementitious materials while utilizing hydration and alkali activation processes. This paper summarizes shrinkage and creep properties of industrially produced H-cement, containing only 20% of Portland clinker. In comparison with a reference cement CEM II/B-S 32.
View Article and Find Full Text PDFJ Environ Manage
September 2024
Key Laboratory of Concrete and Prestressed Concrete Structures of the Ministry of Education, Southeast University, Nanjing, 210096, China.
To address shortages in construction materials for island engineering, tackle the accumulation of solid waste, and inhibit the shrinkage of geopolymers, coral waste was utilized as the internal curing material to prepare high-performance marine geopolymer concrete (MGC) with seawater, sea-sand, and normal limestone aggregate (LsA). The coral coarse aggregate (CorA) used in this investigation has a total porosity ranging from 50% to 58.3% with internal pore diameters spanning 50-400 μm.
View Article and Find Full Text PDFMaterials (Basel)
July 2024
BATir Department (LGC), Université libre de Bruxelles, 1050 Brussels, Belgium.
This research investigates the impact of solution concentration and solution-to-binder ratio (S/B) on the volume changes in alkali-activated slags with sodium hydroxide at 20 °C. Autogenous and thermal strains are monitored with a customized testing device in which thermal variations are controlled. Consequently, both the autogenous strain and coefficient of thermal expansion (CTE) are determined.
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