Recycled additions for improving the thermal conductivity of concrete in preparing energy storage systems. (15th March 2017)

• Record Type: Journal Article
• Authors: Girardi, F.; Giannuzzi, G.M.; Mazzei, D.; Salomoni, V.; Majorana, C.; Di Maggio, R.
• Is Part Of: Construction & building materials. Volume 135(2017)
• Page Start: 565
• Page End: 579
• Publication Date: 2017-03-15
• Subjects: CSP concentrated solar power -- TES thermal energy storage -- PCM phase change materials -- HTF heat-transfer fluid -- RA recycled aggregate -- ESEM environmental scanning electron microscope -- EDXS Energy-Dispersive X-ray Spectroscopy -- DSC differential scanning calorimetry -- HT-DSC high-temperature differential scanning calorimetry -- TG thermo-gravimetry -- TPS transient plane source -- fcm mean cylinder-compressive strength -- Rcm mean cube-compressive strength -- Em mean elastic modulus -- CMOD crack mouth opening displacement -- CTOD crack tip opening displacement -- CTE coefficient of thermal expansion -- k thermal conductivity -- Cp specific heat -- Δl/l0 and ε strain -- Δm mass variation; Fibre-reinforced concrete -- Textile carpet waste -- Metallic shavings -- Thermal energy storage device; Building materials -- Periodicals; 624.18
• DOI: 10.1016/j.conbuildmat.2016.12.179
• Languages: English
• ISSNs: 0950-0618

Abstract

Highlights: Different types of concretes were prepared in order to build thermal storage units. Polyamide fibres and metallic phases were used to reduce spalling of concretes. Polyamide fibres and metallic straws were useful for improving thermal conductivity. Concretes with low content of water can be easily moulded by vibration. Abstract: Two types of concretes were prepared in order to build thermal storage units for solar plants having as primary aim to improve thermal conductivity. The first type consists of concrete for casting on site (A), whereas the second for moulding upon vibration (B). Samples of both typologies were prepared changing type of additions or aggregates. The use of recycled materials into concrete (e.g. polyamide fibres from post-consumer textile carpet waste, metallic powders or shavings and steel fibres) was investigated. Fibre-reinforced concretes were tougher (up to 300%) than ordinary ones. All the concretes show high thermal conductivity and are good candidates for an efficient thermal storage unit, but the performances of type B concretes are better than those of type A. Moreover, the morphology of type B concretes appears compact and less cracked, even after thermal treatment at temperature higher than 300 °C. The thermal conductivity of the mix containing polyamide fibres and metallic shavings was 2.74 and 2.13 W/m °C, before and after a thermal treatment of 4 h at 300 °C, respectively.