**9. Applications of geopolymers**

Geopolymers achieve compressive strength of 20 MPa after only 4 h at 20°C. The 28-day compressive strength of geopolymers could be as high as 70–100 MPa [1]. High strength means the easier or higher dissolution of source materials, generating more aluminosilicate species, which are the most important ingredients for geopolymerization process. The reaction extent of source materials can be measured directly by the compressive strengths of prepared geopolymers. The strength of geopolymers is dependent on the strength of gel phase, the amount

On the other hand, geopolymers have excellent thermal stability with low shrinkage (2%). Geopolymers are stable up to 1000–1200°C [4, 58, 82, 83] and have ceramic-like structure [3]. Geopolymers are dimensionally stable in the working range between 250 and 800°C, accordance to Subaer and van Riessen [84]. In order to improve the thermal properties of geopolymers, filler (e.g. granite or quartz) and foaming agents (e.g. Al powder, hydrogen peroxide) have been added during geopolymer mixing. Addition of quartz or granite reduced shrinkage to 1% [85]. In addition, based on Rickard et al. [86], foamed geopolymers reinforced with

Foamed geopolymers have good potential for ambient application as thermal insulator while exhibiting low density and compressive strength. For fire resistance application, materials must have very low thermal conductivity and resistance to thermal damage as to achieve the similar fire rating. Contradict result was reported by Elimbi et al. [87], whereby metakaolin geopolymers decreased in strength when heated between 300 and 900°C. It was explained due to the progressive transformation of geopolymer matrix into crystalline phases. The

of gel phase formed and amorphous nature of the reaction products [73].

254 Cement Based Materials

polypropylene fibers achieved fire rating of at least 1 h (**Figure 15**).

metakaolin geopolymers were warped and glazed with cracks at 1000°C.

**Figure 15.** Cold side temperatures during the fire testing of four mixes of metakaolin geopolymers [86].

Geopolymers have great potential for variety of applications. Some applications have been successfully commercialized and marketed such as PYRAMENT blended cement and GEOPOLYMITE binders. GEOPOLYMITE binders have been used in several fields such as molding, tooling, foundry work, building's thermal insulation and furnace insulation while PYRAMENT blended cement has been adapted in civil engineering in the production of prestressed and precast concrete [90].

order to further enhance the usage of geopolymers in civil engineering, researchers have investigated on one-part geopolymer system [105–107], whereby geopolymer mixture can be prepared by just adding water. The interest of this study is caused by the limitation of geo-

Clay-Based Materials in Geopolymer Technology http://dx.doi.org/10.5772/intechopen.74438 257

n recent year, the study on geopolymers moves toward application as biomaterials. As proven by Pangdaeng et al. [28], geopolymer has good bioactivity and it is improved by the addition of white Portland cement. On the other hand, geopolymer as drug delivery system has also been studied by Jamstorp et al. [108] and Cai et al. [109]. Based on them, geopolymers possess variable pore-structure for the release of drug at target cell. This again extends the application

polymer technology for in-situ application which lowers its economical value.

Mohd Mustafa Al Bakri Abdullah\*, Liew Yun Ming, Heah Cheng Yong and

Center of Excellence Geopolymer & Green Technology, School of Materials Engineering,

[1] Davidovits J. Geopolymers and geopolymeric new materials. Journal of Thermal Analysis.

[2] Davidovits J. 30 years of successes and failures in geopolymer applications. Market trends and potential breakthroughs, in Geopolymer 2002 Conference. 2002, Geopolymer

[3] Davidovits J. Geopolymers: Inorganic polymeric new materials. Journal of Thermal

[4] Provis JL, Lukey GC, van Deventer JSJ. Do geopolymers actually contain nanocrystalline zeolites? A reexamination of existing results. Chemistry of Materials. 2005;

[5] Saidi N, Samet B, Baklouti S. Effect of composition on structure and mechanical properties of Metakaolin based PSS-Geopolymer. International Journal of Material Science.

[6] Barbosa VFF, MacKenzie KJD, Thaumaturgo C. Synthesis and characterisation of materials based on inorganic polymers of alumina and silica: Sodium polysialate polymers.

International Journal of Inorganic Materials. 2000;**2**(4):309-317

\*Address all correspondence to: mustafa\_albakri@unimap.edu.my

Universiti Malaysia Perlis (UniMAP), Kangar, Perlis, Malaysia

institute, Saint-Quentin, France: Melbourne, Australia

of geopolymers in the medical fields.

Muhammad Faheem Mohd Tahir

1989;**35**(2):429-441

**17**:3075-3085

2013;**3**(4):145-151

Analysis. 1991;**37**:1633-1656

**Author details**

**References**

Besides, geopolymers have been used to produce high-quality brick and tiles. Previously, kaolinite geopolymers are formed through low-temperature geopolymeric setting (L.T.G.S.) followed by ultra-rapid fire at 1000–1200°C to form bricks and tiles [4]. Up to now, this similar method has still being investigated by several researchers [91]. The geopolymer ceramics are non-burning and fire resistant. Furthermore, a new development of ceramic materials is compressing geopolymer powder using powder metallurgy method followed by sintering at 1000–1200°C [92].

In 1994, fireproof geopolymer fiber-reinforced composites have been used for aviation applications as aircraft composites and cabin interiors (floor panels, sidewalls, ceiling and partitions) to eliminate cabin fire during the aircraft accidents. The idea was arised from the problem of the existing plastic materials that were combustible and emitted flammable gases when they burnt. Besides, geopolymers have been used by Formula One teams in car manufacturing due to its corrosive, fire and heat resistance [4].

Concern toward lightweight materials for easy transportation and less energy consumption has led to lightweight concrete materials from geopolymers in civil engineering [93]. Furthermore, the lightweight concrete facilitates structural loading bearing and acts as thermal insulator [94]. Studies on foamed geopolymers in thermal insulation materials for housing construction have also been studied [95]. Zhang et al. [96] made reflective and heat insulative coating from geopolymers. With the addition of pigments and fillers (such as hollow glass microspheres, talc powder and titanium dioxide), wetting agent, dispersing agent and water-retaining agent, the coating produced has 90% reflectivity and thermal insulation performance up to 24°C. Apart from thermal insulative properties, the synthesis of geopolymer for acoustic insulation has been reported by Hung et al. [97]. Geopolymers can adequately and potentially become sound insulating materials in construction and buildings. The density of geopolymer matrix affects the noise reduction coefficient.

In addition, according to Temuujin et al. [98], geopolymers are capable of anti-ultraviolet and antiaging, which made them suitable as coating for exterior wall building to conserve energy. The studies on the thermal and fire performance of geopolymers have also been reported elsewhere [81, 99–101]. As mentioned earlier, geopolymers have molecular structures to resemble zeolitic materials. As such, they are able to immobilize toxic waste or heavy metals as they can absorb and solidify toxic chemical waste. This is beneficial to the immobilization technology [84, 102].

Porous geopolymers were prepared by Okada et al. [89] for use in cooling system. This idea was come about due to high water retention properties or slow water releasing properties of geopolymers. This makes geopolymers suitable for surface cooling by water evaporation that helps to curb the rising earth temperature due to human activities and country development. Potential use of geopolymer in infrastructure rehabilitation was suggested by Pacheco-Torgal et al. [103]. Geopolymer paste can function as sealer for structures and replaced epoxy adhesives in fiber-reinforced polymer retrofiting. Almost similar research was carried out by Geraldes et al. [104], whereby geopolymers are used as restoration materials for tiles. In order to further enhance the usage of geopolymers in civil engineering, researchers have investigated on one-part geopolymer system [105–107], whereby geopolymer mixture can be prepared by just adding water. The interest of this study is caused by the limitation of geopolymer technology for in-situ application which lowers its economical value.

n recent year, the study on geopolymers moves toward application as biomaterials. As proven by Pangdaeng et al. [28], geopolymer has good bioactivity and it is improved by the addition of white Portland cement. On the other hand, geopolymer as drug delivery system has also been studied by Jamstorp et al. [108] and Cai et al. [109]. Based on them, geopolymers possess variable pore-structure for the release of drug at target cell. This again extends the application of geopolymers in the medical fields.
