Cement Chemistry

Mission

The Cement Chemistry group, created in 1986, has a long experience in the study, development and characterization of construction materials, especially cements and concretes. Most of its research lines are oriented towards the development of new materials with a lower carbon footprint, more sustainable and with better mechanical and durable performance. The group’s main interests can be summarised as: i) Chemistry of cement and concrete (processing, hydration, rheology, properties, durability, additives, additions, etc.); ii) Development of new cements and concretes: special cements, belite cements, alkaline cements (Geopolymers), hybrid cements, etc. ii) Materials for the conservation of historical and cultural heritage.

The Cement Chemistry Group is a pioneer, both nationally and internationally, in the development of low-energy cements and new conglomerates based on the alkaline activation of aluminosilicates.

Its scientific and technical research work in the field of construction materials is carried out within the framework of national and international projects (more on construction (national and international). It is a research group with a very remarkable scientific production, as shown by its more than 100 articles in high impact journals in the last 10 years. The members are also authors of several invention patents. They also have a great experience in training researchers with more than 12 Theses read in the last 10 years. It is a reference group and welcomes national and foreign students (pre- and post-doctoral) in its laboratories for temporary stays.

Staff

Research Lines

Portland Cement

General purpose: to explore the manufacture of Portland cement from various waste or industrial by-products. Waste recovery in cement manufacture

  • Study of natural radioactivity (NORM) in cements and raw materials for their manufacture. Effect of mineral additions and other supplementary materials
  • General purpose: To know the influence of NORM waste on the preparation and properties of cements and concretes (conventional and alkali/geopolymer activated cements).

Hydration and durability of Portland cement

General purpose: To develop cements that are resistant to sulphate attack either by the formation of etringite, thaumazite, gypsum, etc:

  • To study the influence of additives added to concrete on the formation of
  • To study the effect of adding witerite to the cement and to evaluate this material as a possible inhibitor of sulphate attack.

Special cements and concretes

General purpose: To know the capacity of different calcium aluminates as activators of ternesite.

To study the hydration of different synthetic calcium aluminates in the presence of ternesite and in media of different alkalinity.

We work on thermodynamic modelling of these processes.

  • Synthesis of pure phases present in cements
  • Hydration studies
  • Hydration of different calcium aluminates and synthetic calcium silicates in isolation or by their joint interaction in media of different alkalinity, as well as their interaction with aluminosilicates (SCMs)
  • Concretes with recycled aggregates. Behaviour and properties

Chemical concrete additives

General purpose: To study the effect of chemical additives for concrete in different cementing systems: Portland cements, calcium aluminate cements and alkaline cements.

Work is done in two areas:

  1. a) – To know the influence of super-plasticising additives on the rheological behaviour of pastes, mortars and concretes. Measurement of the adsorption of these additives on Portland cement as well as on mineral additions;
  2. b) In the formulation of new chemical recipes that, in addition to providing the usual properties of fluidization, modification of air content, etc., also significantly enhance the mechanical development at early age.

 

We work on

  • Determination of the thickness of the adsorbed polymer layer by Atomic Force Microscopy (AFM)
  • Establishing the dispersion mechanisms exerted by super-plasticising additives.
  • Compatibility of additives for concrete with different cementitious materials.
  • Effect of additives on the hydration and properties of cement, mortar and concrete.
  • Characterization of the microstructure of cement pastes and mortars with additives
  • Mortar durability
  • Development of new chemical additives

Alkaline Cements and Concretes (Geopolymers)

General purpose: To develop new cementitious materials based on the alkaline activation of various materials of a silico-aluminous nature (industrial by-products (fly ashes, vitreous slag from blast furnaces…), clays, volcanic rocks, etc.)

We work on establishing the scientific bases on which the synthesis of these new cementitious materials is based, with the definition of variables and ranges of variation of the same, defining the activation stages and mechanisms with the development of conceptual models and the physical, chemical, mechanical and mineralogical characterization of the new

  • Development and physical, mechanical, mineralogical and microstructural characterization of fly ash and activated slag pastes, mortars and concretes.
  • Definition of activation stages and mechanisms with development of conceptual models.
  • Rheological behaviour of cements, mortars and alkaline cement concretes.
  • Effect of organic additives on properties.
  • Development of new alkaline activators from industrial waste or by-products (glass waste, biomass, etc.)
  • New multi-component alkaline cements and concretes (natural and/or industrial waste)
  • Research the viability of different solid and/or liquid wastes as possible precursors or activators for producing alkaline cements
  • Development of new alkaline cements and concretes from vitreous waste.
  • Manufacture of synthetic glass from natural products or industrial by-products at temperatures below 1200ºC that can be alkali activated.
  • Design of matrices to immobilize toxic, dangerous and radioactive chemical substances (Boron, Cesium, Arsenic, Lead, Chrome, Nickel, etc.).
  • Development of alkaline concretes with recycled aggregates
  • Durability of cements, mortars and alkaline concretes.
  • Effect of organic additives in improving their properties. Development of new compatible additives in alkaline systems

Hybrid cements and concretes

General purpose: Combining knowledge of Portland cement and alkaline cements, work is being done to develop cements with very low contents of Portland cement clinker or belite clinker, and high contents of aluminosilicates.

We work on establishing the scientific bases that will allow the reactivity of the supplementary materials (which become the main component) to be increased in order to develop good mechanical behaviour resistant to initial ages.

  • Development of high resistance cements by alkaline activation of silico-aluminates mixtures with low percentages of Clinker (<30%)
  • Synthesis of gels (C-S-H, C-(A)-S-H, C-A-S-H, C,N-A-S-H, N-A-S-H), compatibility studies, effect of pH and Calcium content on their stability Application of “sol-gel” synthesis techniques
  • Compatibility between the Portland cement and alkaline cement.
  • Mechanical and chemical-mechanical activation of SCMs (fly ash, slag, pozzolans, etc) to improve their reactivity in the production of hybrid cements.
  • Structures and microstructures of new cements
  • Industrial developments; civil engineering applications and 3D printers

Materials for the Preservation of Historical and Cultural Heritage

Purpose: To study the causes, mechanisms and effects of deterioration in materials of the built heritage as well as the interaction of conservation products with stone materials, natural or artificial:

  • Study of anti-graffiti, water repellents, consolidators etc.
  • Development of new repair mortars and desalination devices

Facilities and Resources

  • Chemical test laboratory.
  • Physical testing laboratory: kneading machine, Vicat needle, curing chamber, mills, sieve, presses.
  • Instrumental laboratory FTIR, ATR, ATD/TG, petrographic microscope, isothermal conduction calorimetry, TOC, reactor, paste viscometer, mortar rheometers, furnaces

Scientific articles