Development and optimisation of phase change material-impregnated lightweight aggregates for geopolymer composites made from aluminosilicate rich mud and milled glass powder

Abstract

h i g h l i g h t sPCM vacuum impregnation is very successful for expanded clay lightweight aggregate. Polyester resin coating is able to retain all of the impregnated PCM from leakage. Resin coating is chemically stable and neutral, also improving thermal conductivity. Novel combination of geopolymer and thermal energy storing aggregates evaluated. ME-LWA has a high energy storage capacity of 157 J/g. a r t i c l e i n f o a b s t r a c tMacro-encapsulated aggregates (ME-LWAs) consisting of expanded clay lightweight aggregates (LWAs) impregnated with a paraffin wax phase change material (PCM) was produced. To fully exploit the thermal energy retaining properties of PCM, it is fundamental to retain as much of the PCM as possible within the pores of the LWA. This paper investigates 3 different commercial materials to create a total of 14 different coating regimes to determine the most efficient coating method and material regarding its ability at retaining the PCM. The ME-LWAs are then further used as aggregates in geopolymer binders made from a combination of aluminosilicate rich mud and waste glass. Physical properties such as thermal conductivity and mechanical strength are determined for the geopolymer binder with and without the addition of the ME-LWA. A polyester resin was determined to be the most suitable choice of coating material for the ME-LWA, producing a practically leak-proof coating. The ME-LWA was also determined to be chemically neutral, showed a 42% higher thermal conductivity than the LWA in their raw state and maintained a latent heat of 57.93 J/g before and after being used in the geopolymer binder. Carbon fibres and graphite spray were used to improve the thermal conductivity of the resin coating, however no significant increase was detected. Finally, the compressive strength and thermal conductivity results achieved are acceptable for applications in buildings for enhancement of their energy efficiency.

Waste glass in civil engineering applications—A review

“…Concrete samples containing GFG showed no major change in workability compared to control samples. [168][169][170][171][172][173][174] Similar findings were also observed in other studies, indicating that the use of foam glass could adversely affect the properties of lightweight concrete due to ASR expansion.…”

“…Similarly, other studies have also demonstrated that glass-rich geopolymers prepared by coupling CWG and other wastes could potentially be used in a variety of civil engineering applications. [168][169][170][171][172][173][174]…”

Application of the thermal energy storage concept to novel epoxy–short carbon fiber composites

“…Lightweight polymer matrix composites coupling structural or semistructural functions and TES capability could be successfully applied where weight and volume savings need to be combined with precise temperature control. Even though several papers have recently been published on encapsulated and shape‐stabilized PCMs in various polymer matrixes, only a few papers dealing with the development of structural composites with TES capability can be found. The major parts of the scientific reports deal with sandwich structures for thermal management with or without the introduction of a PCM.…”

Multifunctional glass fiber/polyamide composites with thermal energy storage/release capability

“…Examples of such fields can be the automotive, aerospace, portable electronics and technical garments industries. However, even though there are many examples in the literature of encapsulated and shape stabilized PCMs embedded in a polymer matrix [5,12,17,29,[39][40][41][42], only few papers can be found that deal with the development of polymer composites merging structural and TES functions. Most of the examples of such composites regard sandwich structures that have functions of thermal management with [22] or without [43,44] the use of a PCM.…”