Increasing the reaction kinetics of alkali-activated fly ash binders for stabilisation of a silty sand pavement sub-base

Rı́os, Sara; Cristelo, Nuno; Miranda, Tiago F. S.; Araújo, Nuno Miguel Faria; Oliveira, Joel; Lucas, Ernesto

doi:10.1080/14680629.2016.1251959

Cited by 21 publications

(16 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Hence, the development of low carbon alternative binders using increasing amounts of waste materials has been encouraged (e.g., Consoli et al, 2007). For example, the use of lime and fly ash for soil improvement has been used for decades (Mateos and Davidson, 1962;Ghosh and Subarao, 2001;Consoli et al, 2011), but the activation of fly ash with an alkaline solution is far more effective providing much higher strength (Rios et al, 2016a).…”

Section: Introductionmentioning

confidence: 99%

Mechanical and durability properties of a soil stabilised with an alkali-activated cement

Rı́os

Ramos

Fonseca

et al. 2017

European Journal of Environmental and Civil Engineering

Self Cite

View full text Add to dashboard Cite

Alkali activated cements (AAC) have been extensively studied for different applications as an alternative to Portland cement (which has a high carbon footprint) and due to the possibility of including waste materials such fly ash or slags. However, few works have addressed the topic of stabilised soils with AAC for unpaved roads, with curing at ambient temperature, where the resistance to wetting and drying as well as the mechanical properties evolution over time is particularly relevant. In this paper, a silty sand was stabilized with an AAC synthetized from low calcium fly ash and an alkaline solution made from sodium silicate and sodium hydroxide. The evolution of stiffness and strength up to 360 days, the tensile strength, and the performance during wetting and drying cycles were some of the characteristics analysed. Strength and stiffness results show a significant evolution far beyond the 28 th curing day, but still with a reasonable short-term strength. Strength parameters deduced from triaxial tests were found to be very high with stress-strain behaviour typical of cemented soils. Durability properties related to resistance to immersion and wetting and drying cycles were found to comply with existing specifications for soil-cement, giving validity for its use as soil-cement replacement.

show abstract

Section: Introductionmentioning

confidence: 99%

Mechanical and durability properties of a soil stabilised with an alkali-activated cement

Rı́os

Ramos

Fonseca

et al. 2017

European Journal of Environmental and Civil Engineering

Self Cite

View full text Add to dashboard Cite

show abstract

“…The valorization of fly ash mainly aims at transforming potentially hazardous ash into inert geomaterials with enhanced pozzolanic characteristics, fineness, and various other properties suitable for specialized applications. Geopolymerization is an established fly ash valorization technique that leads to the formation of amorphous three-dimensional aluminosilicate materials that are termed geopolymers [63,64]. The polymerized fly ash material is usually obtained through alkaline activation, treatment with certain highly alkaline solutions such as NaOH or KOH in combination with silicate compounds such as Na 2 SiO 3 or K 2 SiO 3 [65].…”

Section: Valorization Of Pulp and Paper Mill Fly Ashmentioning

confidence: 99%

“…The stabilization of soft and expansive subgrade soils using activated fly ash has shown significant improvement in reaction kinetics and strength gain [22,64,71,77]. The effectiveness of geopolymerized fly ash in terms of the durability properties of rammed earth was also evaluated in some recent research [65,[78][79][80][81].…”

Section: Valorization Of Pulp and Paper Mill Fly Ashmentioning

confidence: 99%

“…Fly ash is very effective as a stabilizer for improving the engineering performance of expansive foundation soils, road subgrades and subbase layers, hydraulic layers, etc. [64,[100][101][102]. Past studies have conducted both laboratory and field experiments to assess the performance of PPFA-stabilized roads based on technical, environmental, and economic considerations [56,103,104].…”

Section: Binder Components For Geotechnical Engineering Applicationsmentioning

confidence: 99%

See 1 more Smart Citation

Pulp and Paper Mill Fly Ash: A Review

Cherian

Siddiqua

2019

Sustainability

View full text Add to dashboard Cite

The continual growth of pulp and paper industry has led to the generation of tremendous volumes of fly ash as byproducts of biomass combustion processes. Commonly, a major part of it is landfilled; however, updated environmental regulations have tended to restrict the landfilling of fly ash due to rising disposal costs and the scarcity of suitable land. The pulp and paper industries are therefore urgently seeking energy-efficient mechanisms and management for the beneficial use of fly ash in an ecological and economical manner. This paper offers a comprehensive review of existing knowledge on the major physicochemical and toxicological properties of pulp and paper mill fly ash to assess its suitability for various bound and unbound applications. The current state of various methods used for the valorization of pulp and paper mill fly ash into more sustainable geomaterials is briefly discussed. This paper also presents promising and innovative applications for pulp and paper mill fly ash, with particular reference to agriculture and forestry, the construction and geotechnical industries, and the immobilization of contaminants. It was identified from a literature review that modified pulp and paper mill fly ash can be environmentally and economically advantageous over commercial coal-based fly ash in various sustainable applications.Sustainability 2019, 11, 4394 2 of 16 use of compost products, etc., are drawbacks of composting [10]. Contaminant-free PPFA has great significance as a soil liming agent and fertilizer in agriculture and forestry [6,11]; however, its direct application requires safety precautions due to its undesirable handling and spreading characteristics and associated health risks [12,13]. Further, high pH and electrical conductivity values of pore water in wood ash might have perturbing effects on the microbial community [14]. In order to withstand extreme conditions, the bacteria may enter a dormant stage, thereby decreasing the microbial population and diversity and ultimately disturbing the ecological balance. PPFA and value-added materials also have multifunctional engineering applications, such as supplementary cementitious material (SCM) in concrete systems, aggregate in pavement construction, binder for soil stabilization, and adsorbent for the immobilization of toxic heavy metals [15][16][17][18][19][20][21][22][23]. Based on a statistical survey conducted on the management and utilization of boiler ashes generated at Canadian pulp and paper mills, it was reported that more than 50% of ash is landfilled, 20-25% is used as a soil amendment (direct application or compost), and less than 20% is used for other beneficial applications such as the construction of embankment fills, the stabilization of pavement layers, and the solidification of wastes. [1,2].This paper reviews the existing knowledge on physicochemical and toxicological properties of PPFA in order to assess its suitability as a sustainable geomaterial for various bound and unbound applications. The bound applications of fly ash in...

show abstract

“…The effects of such parameters for classical binders have been extensively investigated and well documented in the literature [e.g., 10,11]. However, similar investigations are limited for geopolymer-treated soils and the available studies are mainly focused on treatment of sand [e.g., 6,12]. In this paper, a comprehensive study is carried out to investigate the geo-mechanical characteristics of geopolymer-treated (natural) clay based on triaxial experimental tests under undrained condition.…”

Section: Introductionmentioning

confidence: 99%

Strength Characteristics of Clay Stabilized with Fly-ash Based Geopolymer Incorporating Granulated Slag

Abdullah¹,

Shahin²

2019

World Congress on Civil, Structural, and Environmental Engineering

View full text Add to dashboard Cite

The use of traditional binders (e.g., lime or cement) in soil stabilization faces many obstacles of environmental nature, and geopolymers have been recently become an attractive alternative binder that may overpasses such obstacles. However, the literature lacks detailed information in relation to the geo-mechanical characteristics of geopolymer-stabilized soils and this paper fills in part of this gap. The paper presents an evaluation of the stress-strain behavior of two natural clays of different mineralogy treated with fly-ash based geopolymer. Laboratory experiments were performed including the Unconfined Compressive Strength (UCS) tests and Consolidated Undrained (CU) triaxial tests under different confining pressures. The results indicate that the addition of geopolymer increases the strength and stiffness of clay, which contributes to higher uniaxial and triaxial peak stresses. The confining pressure was found to have a considerable influence on the stress-strain behavior and excess pore-water pressure obtained from the CU tests. The results also demonstrate that clay mineralogy is an important factor that affects the stress-strain performance of geopolymer-treated clay.

show abstract

Increasing the reaction kinetics of alkali-activated fly ash binders for stabilisation of a silty sand pavement sub-base

Cited by 21 publications

References 64 publications

Mechanical and durability properties of a soil stabilised with an alkali-activated cement

Mechanical and durability properties of a soil stabilised with an alkali-activated cement

Pulp and Paper Mill Fly Ash: A Review

Strength Characteristics of Clay Stabilized with Fly-ash Based Geopolymer Incorporating Granulated Slag

Contact Info

Product

Resources

About