Shear strength development in dredged sediment stabilized by ternary geopolymer governed by gelation and crystallization

Application of ternary cementless hybrid binders for pervious concrete

The effects of desulfurized gypsum on the mechanical properties of dredged clay with high initial water content stabilized by ternary geopolymer

Experimental investigation on the mechanical performance and microscopic characterization of desulfurization gypsum-reinforced ternary geopolymer

Effects of GGBFS:FA ratio and humid-heat-treating on the mechanical performance and microstructure of the steel slag-based ternary geopolymer

Physico-mechanical and microstructural behaviour of high-water-content dredged sediment treated by vacuum preloading coupled with alkali-activated materials

The degradation of concrete structures in the marine environment is generally caused by sulfate attack and chloride ion penetration. To improve the durability of concrete in the marine environment, fly ash (FA) and ground granulated blast furnace slag (GGBS) were partially used to replace cement in a ternary system. The crushed sand was used to reduce the shortage of river sand. In this study, the concrete containing crushed sand, FA, and GGBS was prepared in the laboratory, in which river sand was partially replaced with crushed sand and cement was substituted with FA and GGBS. The amounts of FA/binder and GGBS/binder were fixed at 20% and 35%, respectively, while the content of crushed sand/fine aggregate was set at 60%. The mechanical properties were investigated via compression and splitting tensile tests. The durability of the concrete was examined using a rapid chloride penetration test, sulfate attack test, accelerated corrosion test, and abrasion-wear resistance test. The results showed that the partial replacement of cement by FA and GGBS improved both the mechanical properties and durability of concrete. The inclusion of FA and GGBS in concrete significantly improved its resistance to chloride permeability, specifically, the total charge passed of the mixture with FA and GGBS decreased from 86.2% to 136.9% in comparison with the mixture without FA and GGBS. The addition of FA and GGBS could reduce the change in the length (i.e., improved sulfate resistance) of concrete when it is in contact with the sulfate solution. The changes in the length of the mixture containing FA and GGBS were 3.5 times and 3.2 times smaller than those of the mixture without FA and GGBS. The concrete mixture containing FA and GGBS has a two-time higher corrosion resistance to chloride ion ingress than conventional concrete without FA and GGBS inclusion. The abrasion resistance was improved significantly with the inclusion of FA and GGBS, the abrasion resistance of the mixtures containing FA and GGBS significantly improved by 52 to 59% in comparison with the mixture without FA and GGBS. These results demonstrate that the inclusion of FA and GGBS in concrete can improve both the mechanical properties and durability of concrete, which can be applied in marine environments for sustainable development.

Performance of sustainable concretes containing very high volume Class-F fly ash and ground granulated blast furnace slag

Properties of CO2-cured cement incorporating fly ash and slag subjected to further water curing

Systematic assessment of a multi–solid waste cementitious material: Feasibility and environmental impact

Preparation and performance of composite activated slag-based binder for cemented paste backfill

Concrete is known as the most globally used construction material, but it releases a huge amount of greenhouse gases due to cement production. Recently, Supplementary Cementitious Materials (SCMs) such as fly ash and Ground Granulated Blast Furnace Slag (GGBFS) have been widely used in concrete to reduce the cement content. However, SCMs can alter the mechanical properties and time-dependent behaviors of concrete and the early age mechanical properties of concrete significantly affect the concrete cracking in the engineering field. Therefore, evaluation of the development of the mechanical properties of SCMs-based concrete is vital. In this paper, the time development of mechanical properties of concrete mixes with various fly ash and GGBFS was experimentally investigated. Four different cement replacement levels including 0%, 20%, 30%, and 40% by fly ash and GGBFS as well as ternary binders were considered. Compressive strength, splitting tensile strength, flexural strength, and elastic modulus of concrete were measured until 28 days. Three additional concrete mixes with ternary binders were also cast to investigate the early-age autogenous shrinkage development until 28 days. In addition, prediction models in existing standards were used and compared to experimental results. The comparison results showed that the prediction models overestimated the compressive strength but underestimated the splitting tensile strength development and autogenous shrinkage. As a result, a model capturing the effect of fly ash and GGBFS on the development of compressive and splitting tensile strength is proposed to improve the prediction accuracy for current standards and empirical models.

As a natural clay mineral, halloysite (Hal) possesses a distinctive nanotubular morphology and surface reactivity. Hal calcined at 750°C (Hal750°C; 0.0, 1.0, 2.0, 4.0, 6.0, 8.0 wt.%) was used to replace ground granulated blast furnace slag (GGBFS; 50.0, 49.5, 49.0, 48.0, 47.0, 46.0 wt.%) and fly ash (FA; 50.0, 49.5, 49.0, 48.0, 47.0, 46.0 wt.%) for the preparation of geopolymer in this study. The effects of the replacement ratio of Hal750°C on setting time, compressive strength, flexural strength, chemical composition and microstructure of the geopolymer were investigated. The results indicated that Hal750°C did not significantly alter the setting time. The active SiO2 and Al2O3 generated from Hal750°C participated in the geopolymerization, forming additional geopolymer gel phases (calcium (aluminate) silica hydrate and sodium aluminosilicate hydrate), improving the 28 day compressive strength of the geopolymers. When the amount of Hal750°C was 2.0 wt.%, the 28 day compressive strength of the ternary (GGBFS-FA-Hal750°C-based) geopolymer was 72.9 MPa, 34.8% higher than that of the geopolymer without the addition of Hal750°C. The special nanotubular morphology of residual Hal750°C mainly acted like reinforcing fibres, supplementing the flexural strength of the geopolymer. However, excessive Hal750°C addition (>4.0 wt.%) reduced compressive and flexural strength values due to the low degrees of geopolymerization and the porous microstructure in the ternary geopolymer. These findings demonstrate that the appropriate addition of Hal750°C improved the compressive strength of geopolymers prepared using GGBFS/FA, which provides essential data for future research and supports the utilization of low-value Hal-containing clays in geopolymer preparation.

Modification mechanism of flue gas desulfurization gypsum on fly ash and ground granulated blast-furnace slag alkali-activated materials: Promoting green cementitious material

Reinforcement of soft clay using industrial residue-based soil stabilizer and recycled fine aggregate: A comprehensive investigation

Optimization design and characterization of slag cementitious composites containing carbide slag and desulfurized gypsum based on response surface methodology