State of the art on geopolymer concrete

Abstract

PurposeImportant differentiating attributes in the procedures used, the characteristic mineral composition of the binders, and the implications these have on the final long term stability and physico-mechanical performance of the concretes produced are identified and discussed, with the intent to improve transparency and clarity in the field of geopolymer concrete technologies.Design/methodology/approachThis state-of-the-art review covers the area of geopolymer concrete, a class of sustainable construction materials that use a variety of alternative powders in lieu of cement for composing concrete, most being a combination of industrial by-products and natural resources rich in specific required minerals. It explores extensively the available essential materials for geopolymer concrete and provides a deeper understanding of its underlying chemical mechanisms.FindingsThis is a state-of-the-art review introducing the essential characteristics of alternative powders used in geopolymer binders and the effectiveness these have on material performance.Practical implicationsWith the increase of need for alternative cementitious materials, identifying and understanding the critical material components and the effect they may have on the performance of the resulting mixes in fresh as well as hardened state become a critical requirement to for short- and long-term quality control (e.g. flash setting, efflorescence, etc.).Originality/valueThe topic explored is significant in the field of sustainable concrete technologies where there are several parallel but distinct material technologies being developed, such as geopolymer concrete and alkali-activated concrete. Behavioral aspects and results are not directly transferable between the two fields of cementitious materials development, and these differences are explored and detailed in the present study.

Evaluation of the properties of a foamed geopolymer developed with different types of metakaolin

“…A geopolymeric product formation can be done by evaluating the operational envelope for synthesizing the geopolymers, i.e., by evaluating the ternary diagram of SiO 2 , Na 2 O, and Al 2 O 3 (Fig. 5a), it was observed that all the samples produced in the present work were contained in the envelope synthesis of geopolymer described in the literature [46,47]. Fig.…”

An Experimental Study on the Mechanical Properties of Low-Aluminum and Rich-Iron-Calcium Fly Ash-Based Geopolymer Concrete

“…Similar chemical reactions also occur in Portland and calcium aluminate cement [9]. The presence of calcium plays an important role in accelerating the geopolymer pavement process [5,10] due to its ability to harden at room temperature [11][12].…”

“…However, the chemical processes behind the formation of geopolymers are not clearly understood. These processes can be simplified into three stages [5][6][7]. The first is the dissolution of silicate and aluminum elements from fly ash dust in an alkaline solution to produce aluminate and silicate species.…”

Characterization and Comparison of Corrosion Layer Microstructure between Cement Mortar and Alkali-Activated Fly Ash/Slag Mortar Exposed to Sulfuric Acid and Acetic Acid

“…Although the microstructures of the AFS and AAS mortar specimens before corrosion were dense, apparently, they suffered more serious attacks by acidic solutions. For specimens immersed in acetic acid, the structure was porous, and some calcium acetate and SiO 2 appeared, indicating the dissolution of C-(A)-S-H gel, which had a long chain structure [32] and was vulnerable in the acidic environment. In addition, the structure of the AAS mortar was more porous than that of the AFS mortar.…”