Abstract:This study focuses to discuss the performance of alkali-activated mortar (AAM) reinforced by Polyvinyl Alcohol (PVA) fiber as a replacement of fine aggregate. Drying shrinkage is a major problem of alkali-activated mortar (AAM). Therefore, in order to reduce shrinkage and improve the performance of the mortar; the Polyvinyl Alcohol (PVA) fiber was introduced to replace the fine aggregate. An experimental test, including flow rate, compressive strength, modulus elasticity, poison's ratio, flexural strength and … Show more
“…Previous investigations have also found similar observations. 32, 38, 39 Figure 6.Compressive strengths of the samples subjected to elevated temperatures.Figure 7.Failure characteristics of LWGM samples. (a) 80%EC – room temperature, (b) 80%EC-1%PVA – room temperature, (c) 60%EC sample exposed to 250°C, (d) 80%EC sample exposed to 250°C, (e) 80%EC-1%PVA sample exposed to 250°C.…”
Section: Resultsmentioning
confidence: 99%
“…Previous investigations have also found similar observations. 32,38,39 The effects of elevated temperature on the mechanical strength of LWGM samples were also investigated herein. The results implied that there was a compressive strength increase for the LWGM samples subjected to 250°C.…”
This research provides an experimental investigation on the properties of fiber reinforced composite materials consisting of lightweight expanded clay aggregates (LECA) and polyvinyl alcohol (PVA) fibers. The influence of temperature (room temperature, 250°C, and 500°C) on the lightweight geopolymer mortar (LWGM) composite materials is also explored. LECA is used as a partial replacement to river sand with 60% and 80%. The base material utilized for LWGM is slag activated by a mixture of sodium silicate and sodium hydroxide solutions. The fresh properties in terms of workability and density were performed. A series of experiments, such as compression, flexural and uniaxial tensile strength tests, were executed to assess the mechanical properties of LWGM composite materials. In addition, the microscopic variations due to the elevated temperature were also evaluated by scanning electron microscopy (SEM) to understand the macro-scale behavior of the samples. The results indicated that increasing the level of LECA replacement caused a reduction in the density and compressive strength of the LWGM. Also, incorporating a 1% PVA fiber volume fraction significantly enhanced the flexural and uniaxial tensile behavior of LWGM composite materials. The compressive strength enhancements were observed at 250°C due to further geopolymerization, while compressive strength reductions were obtained at 500°C due to the vapor impact and difference in thermal expansion. In addition, the load-carrying capacity of all samples increased, and displacement capacity decreased under flexural tests at 250°C. However, the ductile behavior of the PVA incorporating specimens changed to brittle due to the melting of PVA fibers.
“…Previous investigations have also found similar observations. 32, 38, 39 Figure 6.Compressive strengths of the samples subjected to elevated temperatures.Figure 7.Failure characteristics of LWGM samples. (a) 80%EC – room temperature, (b) 80%EC-1%PVA – room temperature, (c) 60%EC sample exposed to 250°C, (d) 80%EC sample exposed to 250°C, (e) 80%EC-1%PVA sample exposed to 250°C.…”
Section: Resultsmentioning
confidence: 99%
“…Previous investigations have also found similar observations. 32,38,39 The effects of elevated temperature on the mechanical strength of LWGM samples were also investigated herein. The results implied that there was a compressive strength increase for the LWGM samples subjected to 250°C.…”
This research provides an experimental investigation on the properties of fiber reinforced composite materials consisting of lightweight expanded clay aggregates (LECA) and polyvinyl alcohol (PVA) fibers. The influence of temperature (room temperature, 250°C, and 500°C) on the lightweight geopolymer mortar (LWGM) composite materials is also explored. LECA is used as a partial replacement to river sand with 60% and 80%. The base material utilized for LWGM is slag activated by a mixture of sodium silicate and sodium hydroxide solutions. The fresh properties in terms of workability and density were performed. A series of experiments, such as compression, flexural and uniaxial tensile strength tests, were executed to assess the mechanical properties of LWGM composite materials. In addition, the microscopic variations due to the elevated temperature were also evaluated by scanning electron microscopy (SEM) to understand the macro-scale behavior of the samples. The results indicated that increasing the level of LECA replacement caused a reduction in the density and compressive strength of the LWGM. Also, incorporating a 1% PVA fiber volume fraction significantly enhanced the flexural and uniaxial tensile behavior of LWGM composite materials. The compressive strength enhancements were observed at 250°C due to further geopolymerization, while compressive strength reductions were obtained at 500°C due to the vapor impact and difference in thermal expansion. In addition, the load-carrying capacity of all samples increased, and displacement capacity decreased under flexural tests at 250°C. However, the ductile behavior of the PVA incorporating specimens changed to brittle due to the melting of PVA fibers.
“…Fly ash-based geopolymer concrete offers excellent mechanical properties and durability, which is not offered by OPC concrete [4]. Researchers found geopolymer-based fly ash has good-performance concrete [28][29][30][31][32][33][34][35][36]. Concrete structures are expected to have good durability and resistance during the planned time.…”
The sulfate environment is one of the conditions that significantly affect the durability of concrete. Sulfate attack causes cracks and affects the quality of the concrete. Therefore, it is necessary to innovate concrete that can withstand the aggression of this sulfate attack. Geopolymer concrete is a breakthrough that can be developed as an alternative material without using Portland cement as the ingredients, yet by using class F fly ash as the primary source material. On the other hand, the availability of class C fly ash with high CaO content is highly abundant in Indonesia. The high calcium content in this fly ash will cause the fresh geopolymer concrete to harden rapidly. Previous studies used sucrose as an additive to overcome this rapid hardening problem. However, its effect on the geopolymer concrete exposed to sulfate ingression requires further investigation. In this study, the geopolymer concrete was produced by using class C fly ash and sucrose. The sulfate ingression was simulated by immersing the concrete specimen in the sodium sulfate solution while the mass changes and compressive strength were examined. pH measurement of the sodium sulfate solution was also carried out to provide a different perspective on the data analysis. Cylindrical specimens, measuring 10 cm x 20 cm, were produced using the dry-mixing method and the characteristic strength of 28 MPa according to SNI 2847-2019. From the results, geopolymer concrete with sucrose showed a high workability performance through the high slump value obtained. Nevertheless, the experimental results also indicated the declining strength of geopolymer concrete after the sulfate exposure. However, only a slight reduction was observed. The strength residue still satisfies the minimum requirement of SNI 2847-2019. It shows the potential of geopolymer concrete to be used as a construction material in a harsh environment with high sulfate content.
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