There is a burgeoning interest in the development of geopolymers as sustainable construction materials and incombustible inorganic polymers. However, geopolymers show quasi-brittle behavior. To overcome this weakness, hundreds of research have been focused on development, characterization, and implementation of fiber-reinforced geopolymers for a wide range of applications. This paper discusses the rapidly developing state-of-the-art of fiber-reinforced geopolymer composites, focusing on material and geometrical properties of construction fibers, and underlying mechanisms on fiber-binder interaction at fresh and hardened states, mechanical properties, toughening mechanisms, thermal characteristics, and environmental durability. It is intended to build a strong conceptual and technical background for what is currently understood on fiber-reinforced geopolymers by tying the subject together with knowns for other similar cementitious composites rather than a historical report of literature.

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Fiber-reinforced geopolymer composites: A review

Geopolymer binder and recycled aggregates are considered as the two important sustainable ingredients in concrete production. Ground granulated blast furnace slag (GGBS) and fly ash combination based geopolymeric recycled aggregates concretes (GRAC) were prepared as a substitution of normal concrete in order to reduce the consumption of ordinary Portland cement and natural aggregates as well as to make use of demolished waste concrete. The aim of this study is to investigate the combined effects of GGBS and fly ash considering water-binder (W/B) ratio on the fresh and hardened properties of alkali activated GRAC. The slump, setting time, compressive strength, stress-strain relation, elastic modulus, Poisson's ratio, toughness and failure mode of alkali activated GGBS and fly ash based GRAC containing 100% recycled coarse aggregates were experimentally examined. In addition, the hydration mechanisms were studied by XRD and SEM. Finally, the failure mechanism of this kind of novel green concrete subjected to compression was revealed. The results show that GGBS and fly ash exhibits a superior synergetic effect on the performance of GRAC, i.e. fly ash and GGBS are mainly responsible for the workability and mechanical properties, respectively. GGBS/fly ash ratio has a significant influence on the fresh and hardened properties of GRAC. Moreover, the effect of W/B ratio on GRAC strongly depends on the GGBS/fly ash ratio. GGBS content at less than 25% was found to slightly influence the consistency and compressive strength of GRAC. The combination of 50% GGBS and 50% fly ash with a 0.5 W/B ratio could provide excellent mechanical performance and workability for GRAC.

Effects of combined usage of GGBS and fly ash on workability and mechanical properties of alkali activated geopolymer concrete with recycled aggregate

Development of greener alkali-activated cement: utilisation of sodium carbonate for activating slag and fly ash mixtures

Review of leaching behavior of municipal solid waste incineration (MSWI) ash.

Drying shrinkage in alkali-activated binders – A critical review

https://josbrouwers.bwk.tue.nl/publications/Journal118.pdf

Reaction kinetics, gel character and strength of ambient temperature cured alkali activated slag–fly ash blends

In this article, the effects of raw materials’ composition on fresh behavior, reaction kinetics, mechanical properties and microstructure of alkali activated slag–fly ash–limestone blends are investigated. The results indicate that, with the increasing content of fly ash and limestone, the slump flow increases. The setting times are shortened when increasing the slag content, while both fly ash and limestone show a negligible influence. The reaction process is slightly accelerated by the presence of limestone due to the extra provided nucleation sites, but the reaction process is mainly governed by the slag. The slag content exhibits a dominant role on strength in this ternary system, while for a constant slag content, the compressive strength increases with the increasing limestone content up to 30%. The microstructure analysis shows that the gel characteristics are independent of the limestone powder content. The presence of limestone in initially high Ca and Al conditions does not lead to the formation of additional crystalline phases, which is different from Portland cement systems. Both physically and chemically bound water contents are slightly increased when limestone powder is incorporated.

https://pure.tue.nl/ws/files/3773437/675658554418454.pdf

Properties of alkali activated slag-fly ash blends with limestone addition

Characterization of alkali activated slag–fly ash blends containing nano-silica

Apply 29Si, 27Al MAS NMR and selective dissolution in identifying the reaction degree of alkali activated slag-fly ash composites

https://pure.tue.nl/ws/files/70278078/Gao_et_al._2017_AEC.pdf

X Xu Gao

Papers

Reaction kinetics, gel character and strength of ambient temperature cured alkali activated slag–fly ash blends

Properties of alkali activated slag-fly ash blends with limestone addition

Characterization of alkali activated slag–fly ash blends containing nano-silica

Apply 29Si, 27Al MAS NMR and selective dissolution in identifying the reaction degree of alkali activated slag-fly ash composites

Characterization and application of municipal solid waste incineration (MSWI) bottom ash and waste granite powder in alkali activated slag