The properties of amorphous geopolymer with silica fume addition after heat treatment was rarely reported in the geopolymer field. Geopolymer was prepared by mixing fly ash and alkali activator. The silica fume was added in 2% and 4% by weight. The geopolymer samples were cured at room temperature for 28 days before exposed to an elevated temperature up to 1000 °C. The incorporation of 2% silica fume did not cause significant improvement in the compressive strength of unexposed geopolymer. Higher silica fume content of 4% reduced the compressive strength of the unexposed geopolymer. When subjected to elevated temperature, geopolymer with 2% silica fume retained higher compressive strength at 1000 °C. The addition of silica fume in fly ash geopolymer caused a lower degree of shrinkage and expansion, as compared to geopolymer without the addition of silica fume. Crystalline phases of albite and magnetite were formed in the geopolymer at 1000 °C.

This paper reviews and explains the potential of more applicable geopolymer binder for use. This method is called: “Dry Mixing Method of Geopolymer Binder-Cement Geopolymer”. The mean is that the geopolymer binder is presented in a dry form (like cement powder), which is contains some solid alkali activator and pozzolan materials. How to use it exactly the same as mixing portland cement in general. Through this dry mixing method, it is expected to create a new industry that produces geopolymer cement. With the presence of geopolymer cement, people no longer need to calculate the composition of molarity ratio of the chemicals in the form of the activator alkali solution and pozzolan materials commonly used (wet method of geopolymer binder). In this paper the author will briefly explain the concept in calculating the composition of dry mixing method of geopolymer binder

This paper deals with the behavior of a geopolymer concrete beam (GCB) under shear load using high calcium content fly ash (FA). The effect of the marine environment on the shear strength of GCB was considered by curing the specimen in a sea splashing zone for 28 days. Destructive and non-destructive tests were carried out to determine the properties of geopolymer concrete in different curing environments. Geopolymer concretes cured at room temperature showed higher compressive strength, slightly lower porosity, and higher concrete resistivity than that of those cured in sea water. From the loading test of the GCB under shear load, there was no effect of a sea environment on the crack pattern and crack development of the beam. The shear strength of the GCB generally exceeded the predicted shear strength based on the American Concrete Institute (ACI) Code.

This paper provides a report about the results of an investigation carried out to understand the effect of Microwave Incinerated Rice Husk Ash (MIRHA) on the mechanical properties of fly ash geopolymer concrete to access the concrete performance development. Fly ash (350kg/m³) and MIRHA (0%, 3%, and 7%) were used as the source materials to replace cement, NaOH and Na₂SiO₃ solutions used as the alkaline liquids for the medium of polymeric reaction. In addition, sugar was used as retarder, as well as three different types of curing regime (ambient, external exposure or oven curing regime). The concrete mixing procedure was adjusted to obtain the proper homogeneity of dry materials and wet ones. In this project, a number of mechanical tests have been conducted including the pull-out test, compressive strength test, flexural strength test, and modulus of elasticity test. It was then observed that the performance of mechanical properties of MIRHA-fly ash geopolymer concrete improved with the use of oven curing as the curing regime for the concrete samples.

Thermal performance, combustibility, and fire propagation of fly ash-metakaolin (FA-MK) blended geopolymer with the addition of aluminum triphosphate, ATP (Al(H₂PO₄)₃), and monoaluminium phosphate, MAP (AlPO₄) were evaluated in this paper. To prepare the geopolymer mix, fly ash and metakaolin with a ratio of 1:1 were added with ATP and MAP in a range of 0–3% by weight. The fire/heat resistance was evaluated by comparing the residual compressive strengths after the elevated temperature exposure. Besides, combustibility and fire propagation tests were conducted to examine the thermal performance and the applicability of the geopolymers as passive fire protection. Experimental results revealed that the blended geopolymers with 1 wt.% of ATP and MAP exhibited higher compressive strength and denser geopolymer matrix than control geopolymers. The effect of ATP and MAP addition was more obvious in unheated geopolymer and little improvement was observed for geopolymer subjected to elevated temperature. ATP and MAP at 3 wt.% did not help in enhancing the elevated-temperature performance of blended geopolymers. Even so, all blended geopolymers, regardless of the addition of ATP and MAP, were regarded as the noncombustible materials with negligible (0–0.1) fire propagation index.

This paper presents a study of the flexural strength of geopolymer concrete beam using high calcium content fly ash (FA) in marine environment, without high heat curing. Two series of beam specimens were loaded to failure to study the effect of chloride environment on the flexural strength of geopolymer concrete beams. Series I specimens were subjected to sea environment, whereas series II were kept at room temperature. Tests performed on concrete cylinders show that the sea water has no effect on compressive and splitting tensile stress of high calcium content FA based geopolymer concrete. However, the ratio of splitting and compressive strength for both series was approximately 44%, almost double than that of normal concrete. In addition, the flexural test of concrete beams shows that the average cracking load for series I specimens was 275% higher than that of series II. However, the ultimate load, crack pattern and deflection characteristic for both series were very similar.