Life Cycle Assessment and Impact Correlation Analysis of Fly Ash Geopolymer Concrete.

Xiaoshuang Shi,Abd El-Fatah Abomohra,Yongchen Liang,Jinqian Luo,Ying Feng,Yanlin Li,Qingyuan Wang,Xiaoqi Wang,Cong Zhang

doi:10.3390/ma14237375

Xiaoshuang Shi, Abd El-Fatah Abomohra + Show 7 more

Open Access

https://doi.org/10.3390/ma14237375

Copy DOI

Journal: Materials	Publication Date: Dec 1, 2021
Citations: 28	License type: CC BY 4.0

Affiliation: Sichuan University, Chengdu University

Abstract

Geopolymer concrete (GPC) has drawn widespread attention as a universally accepted ideal green material to improve environmental conditions in recent years. The present study systematically quantifies and compares the environmental impact of fly ash GPC and ordinary Portland cement (OPC) concrete under different strength grades by conducting life cycle assessment (LCA). The alkali activator solution to fly ash ratio (S/F), sodium hydroxide concentration (CNaOH), and sodium silicate to sodium hydroxide ratio (SS/SH) were further used as three key parameters to consider their sensitivity to strength and CO2 emissions. The correlation and influence rules were analyzed by Multivariate Analysis of Variance (MANOVA) and Gray Relational Analysis (GRA). The results indicated that the CO2 emission of GPC can be reduced by 62.73%, and the correlation between CO2 emission and compressive strength is not significant for GPC. The degree of influence of the three factors on the compressive strength is CNaOH (66.5%) > SS/SH (20.7%) > S/F (9%) and on CO2 emissions is S/F (87.2%) > SS/SH (10.3%) > CNaOH (2.4%). Fly ash GPC effectively controls the environmental deterioration without compromising its compressive strength; in fact, it even in favor.

Highlights

In order to effectively reduce the negative impact of the construction industry on global warming, countries around the world are actively responding to reduce energy consumption and emissions
The present study quantified the CO2 emissions of fly ash Geopolymer concrete (GPC) under different strength grades compared with ordinary Portland cement (OPC) concrete
It investigated the correlation and influence of different impact factors contributing to CO2 emissions and compressive strength based on Multivariate Analysis of Variance (MANOVA) and Gray Relational Analysis (GRA) methods

Summary

Introduction

In order to effectively reduce the negative impact of the construction industry on global warming, countries around the world are actively responding to reduce energy consumption and emissions. For AAM mixtures containing POFA, its relatively low CS and high amount of electricity required for oven drying of POFA lead to the highest intensity of normalized CO2 emissions All these studies came to a similar conclusion that GPC has lower CO2 emissions than OPC concrete under a specific compressive strength. This study has quantified and compared the environmental impact of fly ash GPC and OPC concrete under different strength grades from manufacturing to production and found which steps and materials have significant environmental impacts. This study further demonstrates the advantages of GPC in carbon reduction and helps promote its application It provides designers with a basis for designing mix ratios to produce concrete with adequate compressive strength and low environmental impact

Materials and Sample Preparation

Gray relation degree:

Interpretation of MANOVA on GPC

Interpretation of GRA on GPC

Findings

Conclusions