Mechanical properties and shrinkage performance of one-part-geopolymer based on fly ash and micronized dredged sediments

Abstract

This paper aims to study the drying and autogenous shrinkage of optimized One-Part-Geopolymer binders based on micronized dredged sediments and fly ash. Four One-Part-Geopolymer with 0, 15, 30 and 50% wt of sediments and fly ash were optimized by the variation of SiO2/Al2O3 molar ratio between 3; 3.5; 4; 4.5; 5. Findings shown that the sediments incorporation increases the mechanical strength and decreases the matrix pore size. This improvement is related to two phenomena: the fineness of the sediments which plays the role of nucleation zone in the matrix, and the coexistence of C-A-S-H and N-A-S-H gels as shown by the SEM-EDS. The reduction in the pore size of mortars with the addition of sediments leads to an increase in drying and autogenous shrinkage which have been linked to pore distribution rather than mass loss, unlike ordinary cementitious materials. However, the shrinkage values are still lower than the literature findings.

Keywords

• Shrinkage
• Sediments
• Fly ash
• Microstructure
• Mechanical strength
• One-part-geopolymer