Compressive strength of geopolymer concrete modified with nano-silica: Experimental and modeling investigations

Geopolymers are novel cementitious materials that have the potential to replace conventional Portland cement composites completely. The production of geopolymer composites has a lower carbon footprint and uses less energy than the production of Portland cement. Recently efforts have been made to incorporate different types of nanoparticles (NPs) in geopolymer composites to enhance the properties of the composite with improved performances. Nanotechnology is one of the most active research areas with novel science and valuable applications that have gradually gained attention, especially during the last two decades. Many studies have been undertaken to date in order to understand better the impacts of NPs addition on the fresh, physical, mechanical, durability, and microstructure properties of geopolymer composites. In the current comprehensive review paper, the effects of different NP types on the most essential fresh, mechanical, durability, and microstructure characteristics of geopolymer paste, mortar, and concrete composites were reviewed, analyzed, and discussed in detail. In this regard, more than 280 published papers were used to create an extensive database that includes the main features of geopolymer composites modified with different NPs. In addition, the main mechanisms behind the influence of different NP types on the properties of geopolymer composites were examined. Past progress, recent drifts, current obstacles, and the benefits and drawbacks of these geopolymer composites enhanced with NPs were also highlighted. Based on the findings of this study, the addition of NPs has a promising future for developing high-performance geopolymer composites that the construction industry can efficiently implement due to significant improvements in strength, durability, microstructure by providing additional C–S–H, N-A-S-H, and C-A-S-H gels as well as filling nano-pores in the geopolymer matrix. 

The role of nanomaterials in geopolymer concrete composites: A state-of-the-art review

Mechanical and physical properties of inorganic polymer cement made of iron-rich laterite and lateritic clay: A comparative study

The present project deals with the production of alkali activated concretes based on volcanic and calcined laterite under different curing temperatures (28–80 °C). A fraction of 0–40% calcined laterite was added to improve the reactive phase content and the resulting mixtures were labelled GL0, GL20 and GL40. The raw materials and hardened products were characterized using XRD, FTIR, optical microscopy, mechanical properties and durability. The results depicted that both calcined laterite addition (40%) and curing temperature (28–80 °C) have beneficial influences on the mechanical performance. At 28 days, flexural and compressive strengths ranged between 5.05-5.35 MPa and 39.68–48.80 MPa for GL40 specimens. Water absorption and porosity decreased from 7.23 to 4.51% and 9.70 to 6.01%; 16.70 to 10.32% and 22.20 to 13.80% respectively, for geopolymers GL40 and GL20 samples. Bulk densities values were 2398.44/2400.16; 2362.46/2364.16 and 2338.50/2340.20 kg/m3 for GL40 and GL20 specimens respectively. After 19 weeks of sulfuric acid attack (pH = 1), a significant mass loss (1.28–6.22%) was measured in the geopolymer concretes. This behavior is linked to formation of a strong and compact matrix. The above-mentioned alkali activated concretes appear to be a suitable candidate for engineering applications in extreme conditions.

Evaluation of performances of volcanic-ash-laterite based blended geopolymer concretes: Mechanical properties and durability

Incorporation of the waste glass powder (WGP) as an aluminosilicate precursor material in the geopolymer concrete preparation has been researched for the past twenty years as an alternative to the sustainable construction material because of its significant impact on the reduction of greenhouse gases. This paper reviews the various applications of the WGP in the geopolymer matrix production as binary and ternary source material and the impact of the inclusion of WGP on the fresh and hardened characteristics of geopolymer concrete. More research articles associated with the usage of WGP in geopolymer concrete were published in the last ten years. Collective information on the WGP as an aluminosilicate source material in binary, ternary and quaternary blended geopolymer concrete is not available. This review article sums up the newest findings and developments achieved in the synthesis of geopolymer concrete containing WGP as one of the aluminosilicate source material. The study concludes that WGP could be utilized as an innovative and promising eco-friendly aluminosilicate source material to manufacture geopolymer concrete, thereby providing an environmentally eco-friendly solution for the glass and Portland cement based industries.

A Critical Review of Waste Glass Powder as an Aluminosilicate Source Material for Sustainable Geopolymer Concrete Production

In this study, the effect of nano-silica (NS) and silica fume (SF) on workability, setting time, compressive strength and microstructural properties of fly ash-ground granulated blast furnace slag (FA-GGBFS) based geopolymer concrete (GPC) is investigated. Five mixtures of each containing 0.5%, 1.0%, 1.5%, 2.0% and 2.5% NS and SF are prepared for this investigation. The optimum GPC mixture with NS resulted in compressive strength of 63 MPa and the SF modified GPC achieved a compressive strength of 59.59 MPa after 28 days of outdoor temperature curing (Avg. temp. 31.4℃). The hardened concrete samples are analyzed through X-ray diffraction (XRD), X-ray fluorescence (XRF), field emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FTIR), and petrographic examination, for the better understanding of geopolymer mineralogy, mechanism and microstructure. Results indicate that both NS and SF facilitated a higher degree of geopolymerization, leading to the densification of the geopolymer matrix which led to the improvement of the properties of FA-GGBFS based GPC.

Improvement in Fresh, Mechanical and Microstructural Properties of Fly Ash- Blast Furnace Slag Based Geopolymer Concrete By Addition of Nano and Micro Silica

Asif Aftab

Papers

Improvement in Fresh, Mechanical and Microstructural Properties of Fly Ash- Blast Furnace Slag Based Geopolymer Concrete By Addition of Nano and Micro Silica