Utilization of sodium carbonate activator in strain-hardening ultra-high-performance geopolymer concrete (SH-UHPGC)

Abstract

In this study, strain-hardening ultra-high-performance geopolymer concrete (SH-UHPGC) was produced using Na2CO3, Na2SiO3 and their hybridization (1:1 in mole ratio) as alkaline activators. An ultra-high compressive strength was achieved for all the developed strain-hardening ultra-high-performance geopolymer concrete (i.e., over 130 MPa). Strain-hardening ultra-high-performance geopolymer concrete with hybrid Na2CO3 and Na2SiO3 activators showed the highest compressive strength (186.0 MPa), tensile strain capacity (0.44%), and tensile strength (11.9 MPa). It should be highlighted that very significant multiple cracking can be observed for all the strain-hardening ultra-high-performance geopolymer concrete even at a very low tensile strain level (e.g., 0.1%). According to the reaction heat, microstructures, and chemical composition analyses, strain-hardening ultra-high-performance geopolymer concrete with hybrid activators had the highest reaction degree, while that of Na2CO3-based strain-hardening ultra-high-performance geopolymer concrete was the lowest. It was found that the Na2CO3-based strain-hardening ultra-high-performance geopolymer concrete showed the best sustainability, and the strain-hardening ultra-high-performance geopolymer concrete with hybrid Na2SiO3 and Na2CO3 presented the best overall performance (considering the mechanical performance, energy consumption, environmental impact, and economical potential). The findings of this work provide useful knowledge for improving the sustainability and economic potential of strain-hardening ultra-high-performance geopolymer concrete materials.

Effect of Na2CO3 Replacement Quantity and Activator Modulus on Static Mechanical and Environmental Behaviours of Alkali-Activated-Strain-Hardening-Ultra-High-Performance Concrete

“…In this study, the Si/Al ratio and Ca/(Si + Al) ratio are 2.27-2.46 and 0.34-0.36, respectively, and the compressive strength exceeds 120 MPa. It is worth noting that while the use of a certain Na2CO3 replacement quantity reduces the alkalinity of the activator, it actually increases the compressive strength of ASUHPC (from 122.9 MPa to 126.7 MPa), which is consistent with the findings of Lao et al [57]. Indeed, the optimized Na2CO3 replacement quantity enhances the particle size distribution of fresh alkali-activated paste (as shown in Figure 8), resulting in improved density and, consequently, higher compressive strength of ASUHPC.…”

Assessment of Sustainability and Efficiency Metrics in Modern Methods of Construction: A Case Study Using a Life Cycle Assessment Approach

“…Additionally, environmental material loads are determined by manufacturing processes, which vary based on the adoption of greener processes. For example, concrete's environmental impact can be improved by incorporating substances that reduce its EC and EE [104]. Furthermore, concrete and steel employed in reinforced masonry conform to local seismic design standards, although the utilization of these materials can be optimized and reduced when considering varying regional contexts [23].…”

Evaluating the compressive strength of glass powder-based cement mortar subjected to the acidic environment using testing and modeling approaches

“…Cement manufacturers may cut costs and carbon dioxide emissions by recycling and reusing waste [ 21 – 24 ]. Therefore, there is a critical demand for eco-friendly cement-based materials in the construction industry [ 25 – 28 ]. Moreover, the extraction of natural aggregates releases a considerable proportion of carbon dioxide and causes the depletion of natural resources [ 29 ].…”