Mechanical Properties of Glass-Based Geopolymers Affected by Activator and Curing Conditions under Optimal Aging Conditions

Tai-An Chen

doi:10.3390/cryst11050502

Abstract

Inorganic polymeric materials react slowly at room temperature and therefore, usually require high-temperature curing. This study determined the correlation between temperature and duration in high-temperature curing. The results revealed optimal values for each alkali equivalent of an activator (weight ratio of Na2O/glass powder), curing temperature, and curing duration. Increasing the curing duration and curing temperature had positive effects when the alkali equivalent was lower than the optimal percentage. However, over-curing resulted in the visible cracking of the specimens. Furthermore, despite being initially high, the compressive strength of specimens gradually diminished after standing in air. To ensure the durability of glass-based geopolymers, the curing temperature and duration should not exceed 70 °C, and 1 day, respectively.

Highlights

The relentless usage of natural resources to fuel economic growth has resulted in the problem of resource shortage [1]
Global cement production accounts for 5–7% of global annual greenhouse gas emissions [3,4], and the amount of greenhouse gases generated in cement production is increasing by 5% each year [3]
Developing a low-cost, low polluting inorganic cementing material with low energy requirements as a replacement for Portland cement is crucial for environment protection

Summary

Introduction

The relentless usage of natural resources to fuel economic growth has resulted in the problem of resource shortage [1]. The reuse of waste products and the use of environmentally friendly materials have become growing international concerns [2]. Portland cement is the most commonly used inorganic cementing material in civil engineering; its production involves one grinding process as well as two burning processes at high temperature of 1300~1400 ◦ C, generating 1 ton of carbon dioxide per ton of cement [3]. Global cement production accounts for 5–7% of global annual greenhouse gas emissions [3,4], and the amount of greenhouse gases generated in cement production is increasing by 5% each year [3]. Developing a low-cost, low polluting inorganic cementing material with low energy requirements as a replacement for Portland cement is crucial for environment protection.

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Conclusion