A brief history and review of geopolymer technology is presented with the aim of introducing the technology and the vast categories of materials that may be synthesized by alkali-activation of aluminosilicates. The fundamental chemical and structural characteristics of geopolymers derived from metakaolin, fly ash and slag are explored in terms of the effects of raw material selection on the properties of geopolymer composites. It is shown that the raw materials and processing conditions are critical in determining the setting behavior, workability and chemical and physical properties of geopolymeric products. The structural and chemical characteristics that are common to all geopolymeric materials are presented, as well as those that are determined by the specific interactions occurring in different systems, providing the ability for tailored design of geopolymers to specific applications in terms of both technical and commercial requirements.

Geopolymer technology: the current state of the art

http://www.personal.psu.edu/faculty/g/u/gur/cement%20for%20the%20future.pdf

Alkali-activated fly ashes: A cement for the future

The Role of Inorganic Polymer Technology in the Development of ‘Green Concrete’

Understanding the relationship between geopolymer composition, microstructure and mechanical properties

Carbon dioxide equivalent (CO2-e) emissions: A comparison between geopolymer and OPC cement concrete

The effect of a small quantity of CaF 2 on the capacity of reaction of raw mixes has been studied in this paper; and for this purpose the thermal behaviours of a commercial raw mix without the addition of CaF 2 were compared at different ages of clinkerization.
The times required to complete the reactions at different temperatures are estimated. The mineralizer effect of fluorspar has a maximun at temperatures of clinkerization of about 1.200oC and ages of cinkerization of about 10 minutes.

/pdf/influencia-del-caf-2-sobre-la-capacidad-de-reaccion-de-5a7xf4jkd2.pdf

Influencia del CaF 2 sobre la capacidad de reacción de crudos de cemento

On propose une nouvelle methode de preparation de ciment. Elle est basee sur l'utilisation de CaF 2 et CaSO 4 , remplacant partiellement les matieres premieres usuelles. On montre la possibilite d'utiliser cette nouvelle methode a l'echelle industrielle. Un essai fait dans une cimenterie espagnole, produisant 1500 tonnes de ciment blanc, a montre que cette methode peut etre adaptee a la technologie courante. Elle necessite moins d'energie et le produit final a de relativement bonnes proprietes.

Production of cement requiring low energy expenditure ― An industrial test

Rendering mortars, which are still exposed to the open air on some of the walls of Medina Azahara, are studied and characterized in this work. Some repairing mortars used in different previous restorations are also characterized.
Those rendering mortars are of different make considering the composition of their binder: lime, gypsum and mixed lime/ gypsum. Repairing mortars used in previous interventions are made of lime, excepting for a portland cement used by Felix Hernandez in the restoration of one of the rooms back in the 50's.
Biological colonization is the main cause of decay in lime mortars, while in mortars made of gypsum, decay is a result of the solubilizating action of rain water.

/pdf/rendering-mortars-in-medina-azahara-part-i-material-4idyvmkctc.pdf

Rendering mortars in Medina Azahara, Part I: Material characterization and alteration process

Landfilling of mine and industrial waste streams leads to environmental and economic issues. Sustainable management methods through valorization in manufacturing green construction materials are a current research interest. Here, a promising process for recycling mine tailings, such as phosphate sludge, is proposed. A mixture of phosphate sludge, kaolin clay (Al source), and glass waste (Si source) was prepared. Three fluxing agents were tested at 1000 °C (NaOH, Na2CO3, Na2SO4). Na2CO3 was selected as the most cost-effective. The precursors were alkaline activated with NaOH solution (2, 6, and 8 M). At 28 days of curing (20 h room temperature + 6 h 85 °C + room temperature), the best compressive strength (of more than 45 MPa) was obtained with 8 M NaOH. The reaction products, characterized by XRD, FTIR, SEM, and MAS NMR, show that the main reaction products is a gel N–A–S–H/(N,C)–A–S–H together with some unreacted crystalline phases formed during the fusion. 

Ángel Palomo

Papers

Influencia del CaF 2 sobre la capacidad de reacción de crudos de cemento

Production of cement requiring low energy expenditure ― An industrial test

Rendering mortars in Medina Azahara, Part I: Material characterization and alteration process

Fusion of phosphate by-products and glass waste for preparation of alkali-activated binders

Environmental Deterioration of Ancient and Modern Hydraulic Mortars