In this paper, we report the results of our investigation on the possibility of producing foam concrete by using a geopolymer system. Class C fly ash was mixed with an alkaline activator solution (a mixture of sodium silicate and NaOH), and foam was added to the geopolymeric mixture to produce lightweight concrete. The NaOH solution was prepared by dilute NaOH pellets with distilled water. The reactives were mixed to produce a homogeneous mixture, which was placed into a 50 mm mold and cured at two different curing temperatures (60 °C and room temperature), for 24 hours. After the curing process, the strengths of the samples were tested on days 1, 7, and 28. The water absorption, porosity, chemical composition, microstructure, XRD and FTIR analyses were studied. The results showed that the sample which was cured at 60 °C (LW2) produced the maximum compressive strength for all tests, (11.03 MPa, 17.59 MPa, and 18.19 MPa) for days 1, 7, and 28, respectively. Also, the water absorption and porosity of LW2 were reduced by 6.78% and 1.22% after 28 days, respectively. The SEM showed that the LW2 sample had a denser matrix than LW1. This was because LW2 was heat cured, which caused the geopolymerization rate to increase, producing a denser matrix. However for LW1, microcracks were present on the surface, which reduced the compressive strength and increased water absorption and porosity.

Depending on the processing conditions, geopolymers can exhibit a wide variety of properties and characteristics. Curing profile serves as a crucial parameter in synthesis of geopolymers. In this paper, the influence of curing temperature and curing time on the properties of kaolin-based geopolymer was studied. The samples were separated into several curing conditions; including curing at ambient temperature, 40°C, 60°C, 80°C and 100°C for 1 day, and up to 3 days. The compressive strength and SEM analysis of geopolymer products were evaluated. Results showed that curing condition has a significant effect on the mechanical properties of kaolin-based geopolymer. Generally, curing at ambient temperature was not feasible, while increase in temperature favored the strength development. In addition, prolonged curing time improved the geopolymerization process, and led to higher strength gain. However, curing at high temperature for a long period of time caused failure of the sample at a later age

Fly ash–based geopolymers required heat to increase the geopolymerization process in order to obtain higher compressive strength. As such, geopolymer samples were prepared using different curing temperatures (room temperature, 50°C, 60°C, 70°C, 80°C), in which sodium silicate and NaOH were used as alkaline activators. The samples were cured for 24hours in the oven and tested on the seventh day. The result revealed that the maximum compressive strength (67.04MPa) was obtained at a temperature of 60°C. However when the geopolymers sample cured at temperature more than 60°C, the compressive strength decreased. From the FTIR spectra, the higher content of Si on sample cured at 60°C also contributed to higher compressive strength. Moreover, SEM analysis showed a denser matrix as well as less unreacted fly ash of the sample cured at 60°C compared to other temperatures

The objective of this paper is to produce an environmentally friendly artificial wood for structural application, by recycling mixed plastic waste and date palm leaves waste. Several pretreated wood plastic composites mixtures, using a 1:1 ratio of palm leaves and plastic waste, were designed and developed—namely, polycarbonate (PC-mix), polystyrene (PS-mix), and polyvinyl chloride (PVC-mix). The batch mixture of each type was extruded at different temperature profiles.The density, water absorption, hardness, modulus of elasticity (tensile and flexure), impact strength, and linear burning rate of the WPC samples produced were determined, and the results were compared with the natural hard, soft wood, and medium density fiberboard (MDF) woods. The developed wood plastic composites exhibited less water absorption, linear burning and hardness, higher density than that of natural and MDF wood, and can be used in outdoor structures

This paper presents the results of a study on the effect of temperature on geopolymers manufactured using pozzolanic materials (fly ash). In this paper, we report on our investigation of the performance of porous geopolymers made with fly ash after exposure to temperatures from 600 °C up to 1000 °C. The research methodology consisted of pozzolanic materials (fly ash) synthesized with a mixture of sodium hydroxide and sodium silicate solution as an alkaline activator. Foaming agent solution was added to geopolymer paste. The geopolymer paste samples were cured at 60 °C for one day and the geopolymers samples were sintered from 600 °C to 1000 °C to evaluate strength loss due to thermal damage. We also studied their phase formation and microstructure. The heated geopolymers samples were tested by compressive strength after three days. The results showed that the porous geopolymers exhibited strength increases after temperature exposure.