Abstract
This paper presents temperature-dependent properties and fire resistance of geopolymer foams made of ground basalt fibers, aluminum foaming agents, and potassium-activated metakaolin-based geopolymers. Temperature-dependent properties of basalt-reinforced geopolymer foams (BGFs) were investigated by a series of measurements, including apparent density, water absorption, mass loss, drying shrinkage, compressive and flexural strengths, XRD, and SEM. Results showed that the apparent density and drying shrinkage of the BGFs increase with increasing the treated temperature from 400 to 1200 °C. Below 600 °C the mass loss is enhanced while the water absorption is reduced and they both vary slightly between 600 and 1000 °C. Above 1000 °C the mass loss is decreased rapidly, whereas the water absorption is increased. The compressive and flexural strengths of the BGFs with high fiber content are improved significantly at temperatures over 600 °C and achieved the maximum at 1200 °C. The BGF with high fiber loading at 1200 °C exhibited a substantial increase in compressive strength by 108% and flexural strength by 116% compared to that at room temperature. The enhancement in the BGF strengths at high temperatures is attributed to the development of crystalline phases and structural densification. Therefore, the BGFs with high fiber loading have extraordinary mechanical stability at high temperatures. The fire resistance of wood and steel plates has been considerably improved after coating a BGF layer on their surface. The coated BGF remained its structural integrity without any considerable macroscopic damage after fire resistance test. The longest fire-resistant times for the wood and steel plates were 99 and 134 min, respectively. In general, the BGFs with excellent fire resistance have great potential for fire protection applications.
Highlights
The term “Geopolymer” was first introduced by Joseph Davidovits in the late 1970s [1].Geopolymer material is an amorphous aluminosilicate binder material
Geopolymers have been shown as a green alternative to ordinary Portland cement (OPC) due to their excellent mechanical properties, low permeability, low CO2 emissions, good chemical resistance, and excellent fire resistance [2]
basalt-reinforced geopolymer foams (BGFs) were prepared by three following steps: (1) to begin with, a geopolymer mortar was prepared by mixing metakaolin-based geopolymer Baucis lk with an alkaline solution of potassium in prepared by mixing metakaolin-based geopolymer Baucis lk with an alkaline solution of potassium a predetermined ratio by mechanical stirring; (2) afterwards, the ground basalt fibers in a predetermined ratio by mechanical stirring; (2) afterwards, the ground basalt were added to the geopolymer mortar mixture and the mixture was homogenized by the mechanical fibers were added to the geopolymer mortar mixture and the mixture was homogenized by the stirring; and (3) aluminum powders were added to the mixture to create the BGF
Summary
The term “Geopolymer” was first introduced by Joseph Davidovits in the late 1970s [1]. Among the products based on geopolymers, geopolymer foams (GFs) with highly porous structures have been considered as the most attractive materials over the past few years, because they possess exceptional properties, lightweight, low cost, and good fire and chemical resistances [4,5,6]. Peng et al [28] reported that the amorphous skeleton structures of alkali-activated GFs have been converted to smooth ceramics after the treatment at high temperatures These GFs have a stable porous structure and extraordinary fire resistance. Acid-based geopolymer materials could maintain structural stability and excellent mechanical properties at high temperatures [37,38]. Effects of high temperatures to 1200 ◦ C on the physical and mechanical properties of the BGFs, namely apparent density, water absorption, mass loss, drying shrinkage, and compressive and flexural strength were investigated.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
