CONICET | Buscador de Institutos y Recursos Humanos

Nowadays, different properties are expected for building materials. Durability andhigh resistance are the common requirements, but every day more applicationsdemand reduced weight as a required property. As a means of reducing environmentalimpact, sustainable construction requires considering not only the type of materialsused, but also the way they affect the building process and the long-term performanceof the structure. Lightweight materials are known for their insulating properties, thuslow-energy conditioning of housing is one of the main reasons for their use in construction.However, these materials usually have poor mechanical properties. For thisreason, lightweight materials are mostly used in nonstructural applications, such ascovering mortars for walls, flat roof insulation, or concrete sandwich wall panels. Inthese cases, different approaches to lower the density of cement-based materials canbe considered, such as using lightweight/low-strength aggregates, like expanded polystyrene(EPS), or increasing the water-to-cement ratio.Despite these approaches that tend to reduce the mechanical properties, it is alsopossible to reduce the density of a material and maintain a satisfactory strength. Forexample, cement can be replaced with lightweight/high-strength aggregates such ashollow glass microspheres (HGMSs), which are widely used for oil well lightweightcement slurries. These slurries usually require low density, as the pressure theyexert over the formation when pumping it, which directly depends on density, is alimiting variable for its application. Another way to obtain lightweight cementbasedmaterials with acceptable resistance is to enhance the mechanical propertiesof the binder.This chapter reviews three techniques for lightening cement-based materials:using EPS, HGMSs, and additives known in the oil well industry as extenders. Bothinsulating and mechanical properties are specially studied.

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