Low-Density Geopolymer Composites for the Construction Industry

Abstract

The article presents preliminary results in studying reinforced and light-weight geopolymers, which can be employed in buildings, especially for walling. Such materials are very promising for the construction industry having great potential due to their favorable properties such as high mechanical strengths, low thermal conductivity, and low density. Moreover, they also exhibit several advantages from an economic and ecological point of view. The present study exanimated the use of specific fillers for the metakaolin-based light-weight geopolymers, emphasizing the above-mentioned physical properties. This research also investigated the electromagnetic shielding ability of the carbon grid built into the light-weight geopolymer structure. According to the study, the most suitable materials to be used as fillers are polystyrenes, along with hollow ceramic microsphere and Liapor. The polystyrene geopolymer (GPP) achieves five times lower thermal conductivity compared to cement concretes, which means five times lower heat loss by conduction. Furthermore, GPP is 28% lighter than the standard geopolymer composite. Although the achieved flexural strength of GPP is high enough, the compressive strength of GPP is only 12 MPa. This can be seen as a compromise of using polystyrene as a filler. At the same time, the results indicate that Liapor and hollow ceramic microsphere are also suitable fillers. They led to better mechanical strengths of geopolymer composites but also heavier and higher thermal conductivity compared to GPP. The results further show that the carbon grid not only enhances the mechanical performances of the geopolymer composites but also reduces the electromagnetic field. Carbon grids with grid sizes of 10 mm × 15 mm and 21 mm × 21 mm can reduce around 60% of the Wi-Fi emissions when 2 m away from the signal transmitter. Moreover, the Wi-Fi emission was blocked when the signal transmitter was at a distance of 6 m.

Keywords: Liapor; carbon fiber grid; ceramic microsphere; light-weight geopolymers; polystyrene; walling materials.

Figure 1

Raw materials used as fillers: (a) Liapor, (b) glass microspheres, and (c) EPS polystyrene.

Figure 2

Sample GP (a), and thermal conductivity device: HFM436 Lambda (b).

Figure 3

The box used for electromagnetic tests.

Figure 4

The compressive strengths of the studied samples.

Figure 5

The compressive strength profiles of GPL and GPP through the volume fraction of the fillers.

Figure 6

The flexural strengths of the samples compared to GP.

Figure 7

The flexural strengths profiles of GPL and GPP on the relative fillers expressed as a volumetric percentage.

Figure 8

Physical properties of the samples studied.

Figure 9

Signal shielding performance of the carbon grids along the test area.