An environmental evaluation of geopolymer based concrete production: reviewing current research trends

Alkali-activated materials

“…A detailed recent discussion of life-cycle analysis (LCA) of alkali-activated binder systems has been provided by Habert and Oullet-Plamondon [45], who examined in detail many of the recent discussions and debates around this still-contentious issue, and the reader is referred to that work for a much more comprehensive analysis than is presented here. Examples of LCA studies of alkali activation include [9,45,[71][72][73][74][75][76][77][78][79], and these studies have resulted, in general, in calculations of between 40-80% CO2 emissions reduction for the use of alkali-activated binders compared to a Portland cement baseline. However, the baselines are specified inconsistently between reports, and local conditions (including transport distances and electricity generation mix) as well as the choice of mix design for assessment will have important impacts on the results of the analysis.…”

“…Additionally, some extremely conservative assumptions were made regarding emissions of components such as chloride [79], which have carried through into product assessments for alkali-activated materials which thus appear to be much more environmentally damaging than Portland cement across various non-CO2 emissions categories [45,71]. This may or may not be the case in reality when database figures are updated to reflect modern waterglass production practices, and such calculations must be carried out in the future to provide a true assessment of the environmental footprint of alkaliactivated binder systems.…”

Geopolymer/PEG Hybrid Materials Synthesis and Investigation of the Polymer Influence on Microstructure and Mechanical Behavior

“…These materials were first introduced as calcium-free inorganic cements by Davidovits in 1978 4 and since then they have been attracting increasing attention due to their promising characteristics. They have been mainly proposed as more environmentally friendly substitutes of Portland cement 5,6 because of the greater energy efficiency of their manufacturing process and the substantial reduction in CO 2 emissions 7,8 . Following the particular aluminosilicate precursor 3 , the stoichiometric ratio of Si/Al [1,9] , alkali hydroxide and water content 10,11 as well as the reaction temperature, pressure 3 , activation, setting and curing procedures 11,12 , geopolymers can exhibit a wide variety of properties, such as high compressive strength, low shrinkage, fast or slow setting, acid and fire resistance, low thermal conductivity, long term durability and thermal stability.…”

The Effect of HCWA-PFA Hybrid Geopolymer Modification on the Properties of Soil

“…Geopolymers are usually obtained through inexpensive and eco-friendly synthetic procedures with low waste gas emission [9,12,13,21]. For these reasons they are considered "green materials" [11].…”