The American Society for Testing and Materials (ASTM) is an independent organization devoted to the development of standards.

American Society for Testing and Materials

Shape-Memory Materials

Geopolymer is a new environment-friendly cementitious material, and the development of geopolymer can reduce the carbon dioxide emission caused by the development of cement industry. Geopolymer materials not only have excellent mechanical properties, but also have a series of excellent properties such as fire resistance and corrosion resistance. Most industrial solid waste and waste incineration bottom ash are piled up at will, which not only occupies land resources, but also has a bad impact on the environment. Recycling them can be used as raw materials for preparing geopolymers. Geopolymer materials can effectively adsorb heavy metals, dyes, and other radioactive pollution, which is very beneficial to society's future development. However, due to the excellent properties of geopolymer materials, its application goes beyond that. Some useful information about geopolymer materials was introduced in this paper. The paper included the geopolymerization, the source of raw materials, the types of activators, the preparation methods, and the different application fields of geopolymer materials. The factors affecting the fresh properties and mechanical properties of geopolymer materials were discussed. In this paper, the shortcomings and application limitations of geopolymer materials were summarized, and their progress was summarized to lay a theoretical foundation for the long-term development of geopolymer materials.

Advances in geopolymer materials: A comprehensive review

Fly ash in concrete

Natural fiber reinforced high calcium fly ash geopolymer mortar

Mechanical properties and microstructure analysis of FA-GGBS-HMNS based geopolymer concrete

This investigative study aims to study the mechanical and morphological properties of fly ash (FA)-based geopolymer paste as a repair material when applied on ordinary Portland cement (OPC) overlay concrete. The first part of this study investigates the optimal mix design of FA-based geopolymer paste with various NaOH concentrations of 8, 10, 12, and 14 M, which were used later as a repair material. The second part studies the bonding strength using a slant shear test between the geopolymer repair material and OPC substrate concrete. The results showed that a shorter setting time corresponds to the higher NaOH molarity, within the range of 53 and 30 min at 8 and 14 M, respectively. The compressive strength of FA-based geopolymer paste was found to reach 92.5 MPa at 60 days. Also, from the slant shear test results, prism specimens with 125 mm length and 50 mm wide have a large bond strength of 11 MPa at 12 M. The scanning electron microscopy/energy-dispersive X-ray (SEM/EDX) analysis showed that the OPC substrate has a significant effect on slant shear bond strength, where the presence of free cations of Ca2+ on the OPC substrate surface contributed to the formation of calcium alumina-silicate hydrate gel (C-A-S-H) by building various cross-links of Ca-O-Si.

Bonding Strength Characteristics of FA-Based Geopolymer Paste as a Repair Material When Applied on OPC Substrate

The influence of zinc oxide (ZnO) nanoparticles on the mechanical properties and photocatalytic degradation of methylene blue (MB) of ZnO-based geopolymer material was investigated under the illumination of ultraviolet (UV) radiations. In this work, ZnO-based geopolymer paste was manufactured using class F fly ash (FA) and ZnO nanoparticles powders with different mass percentages (0, 2.5, 5.0, 7.5 and 10 wt%). The FA-ZnO dry mix was activated by alkaline activator solution made from sodium silicate and sodium hydroxide with a ratio of 2.5. The mechanical properties were investigated by performing a compressive strength test at 28 days. The photocatalytic activity of ZnO nanoparticles was evaluated by measuring the photodegradation level of methylene blue under sunlight rays. The results showed a substantial influence of ZnO on the compressive strength, which decreased with the increase of ZnO amounts ranging from 2.5 to 7.5 wt% then a slightly increased at 10 wt% of ZnO. The addition of ZnO nanoparticles to a geopolymeric material showed a satisfactory efficiency of photocatalytic degradation of methylene blue after 150 min of exposure to sunlight. Phase analysis revealed that the addition of ZnO nanoparticles in the geopolymeric system develops a new ZnO crystalline phases.

Influence of ZnO Nanoparticles on Mechanical Properties and Photocatalytic Activity of Self-cleaning ZnO-Based Geopolymer Paste

\nThis paper presents a review on fly ash as prime materials used for geopolymer. Due to its advantages of abundant resources, less in cost, great workability and high physical properties which lead to achieve high mechanical properties. Fly ash is considered as one of the largest generated industrial solid wastes or so-called industrial by products, around the world particularly in China, India and USA. The characteristics of fly ash allow it to be a geotechnical material to produce geopolymer cement or concrete as an alternative of Ordinary Portland cement. Many efforts are made in this direction to formulate a suitable mix design of fly ash based-geopolymer by focusing on fly ash as the main prime material. The physical properties, chemical compositions and chemical activation of fly ash are analysed and evaluated in this review paper. Reference has been made to different ASTM, ACI standards and other researches work in geopolymer area.\n

A Review on Fly Ash as a Raw Cementitious Material for Geopolymer Concrete

For the industrial applications of self-sensing multi-walled carbon nanotubes (MWCNTs)/polymers nanocomposites, it is very important to investigate their behavior under complex experimental conditi...

Aissa Bouaissi

Papers

Mechanical properties and microstructure analysis of FA-GGBS-HMNS based geopolymer concrete

Bonding Strength Characteristics of FA-Based Geopolymer Paste as a Repair Material When Applied on OPC Substrate

Influence of ZnO Nanoparticles on Mechanical Properties and Photocatalytic Activity of Self-cleaning ZnO-Based Geopolymer Paste

A Review on Fly Ash as a Raw Cementitious Material for Geopolymer Concrete

Mechanical and electrical behaviors of self-sensing nanocomposite-based MWCNTs material when subjected to twist shear load