Ettringite Formation Research Articles

Early age accelerated carbonation of cementitious materials surface in low CO2 concentration condition

Accelerated carbonation curing contributes to the carbon sequestration effect of cementitious materials and enhances surface density. However, in large-scale applications, traditional high CO2 concentration conditions (>5 % CO2) are constrained by economic costs. This study traces the early-stage accelerated carbonation process of cement mortar under low CO2 concentration (3 % CO2) condition from the perspectives of the evolution of CaCO3 crystal types, phase transformations, and microstructural changes, and compares the results with those under the 20 % CO2 condition. The results show that the carbonation depth of mortar specimens cured under the 3 % CO2 condition is shallower, but the cumulative concentration of CaCO3 within the surface 3 mm is not significantly lower than that under the 20 % CO2 condition; The carbonation zone generates more low-crystalline forms of CaCO3; The accelerated carbonation process does not affect the formation of CH and ettringite. Microscopic results indicate that under the 3 % CO2 condition, the synergistic effects of hydration and carbonation are better, and appropriately extending the curing time helps to refine the pore structure of the carbonation zone and improve the density of the substrate surface.

Phase development and mechanical strength of limestone calcined clay cement utilising Australian bentonite and plasterboard waste

The potential of a calcined Australian bentonite (CB) to produce low embodied carbon limestone-calcined-clay-cement with 50 % clinker replacement was compared against metakaolin (Mk). Recycled plasterboard waste (PW) was also investigated as an alternative to virgin gypsum to enhance cement sustainability. CB-based cement blends exhibited greater pozzolanic reactivity, improved phase development and greater 28-day compressive strength compared to Mk-based blends, as confirmed by X-ray diffraction, thermogravimetry, infrared spectroscopy and electron microscopy. Reactive silica from CB promoted formation of calcium-silicate-hydrates with higher Si/Ca and lower Al/Ca ratios, as well as more alumino-silicate phases (strätlingite), whereas Mk favored formation of ettringite and carbo-aluminates. Additional sulphates enhanced ettringite and carbo-aluminate formation, and PW improved early age pozzolanic reactivity in both blends as confirmed by thermal analysis. This study demonstrated that both the CB and PW show great potential for producing low embodied carbon cement, highlighting that other local clay-mineral resources should also be investigated.

Hydration characteristics and hydration products of calcium sulfoaluminate cement and fly ash blended pastes

This study investigated a binary blend of calcium sulfoaluminate cement and fly ash with a target compressive strength of more than 32.5 MPa based on the EN 197-1 standard, using as much fly ash as possible. In the binder system of calcium sulfoaluminate cement and fly ash, a decrease in the replacement level of fly ash results in an increase in compressive strength. Mortar with a 40% replacement level of fly ash for calcium sulfoaluminate cement and added gypsum shows 49.41 MPa strength at 28 d. Its hydrates are hydroxy-AFm, ettringite, crystalline aluminum hydroxide, amorphous aluminum hydroxide, strätlingite, and monosulfate. They are attributed to the hydration of ye’elimite, C2S, and C3A in calcium sulfoaluminate cement. The reactivity of fly ash is not observed until 28 d of hydration. The formation of ettringite is the main cause of the gains in compressive strength.

Characterization of a fly ash-based hybrid well cement under different temperature curing conditions for natural gas hydrate drilling

This paper presents a study on the temperature effect (3°C, 10°C, and 50°C, in water bath) and activator effect on the characterization of a fly ash-based hybrid well cement, with a large fraction of fly ash (approximately 70 %), which has potential for natural gas hydrate drilling due to its low heat release. The mechanical strength, micro/nanostructure characteristics were investigated through various tests, including x-ray diffraction (XRD), thermogravimetry analysis (TGA-DTG), nuclear magnetic resonance (MAS NMR), and scanning electron microscope (SEM), to reveal the hydration mechanism of the fly ash-based hybrid well cement. The results indicate that the low curing temperatures (3°C, 10°C) inhibited both the hydration of the well cement and the pozzolanic reaction of fly ash in the cement system. However, the incorporation of solid Na2SO4 significantly contributed to the pozzolanic reaction during the hydration process by consuming more calcium hydroxide, promoting more ettringite formation and reducing the apparent activation energy of the blend cement (from 53.06 kJ·mol−1 to 41.23 kJ·mol−1), resulting in better compressive strength. MAS NMR results showed that the addition of solid Na2SO4 facilitated the substitution of Al with Si atoms, leading to the formation of more C-A-S-H and C-(N)-A-S-H gels in the system with a denser microstructure. Overall, the fly ash-based hybrid well cement can be developed as a cement system for natural gas hydrate drilling in the ocean. This cement not only exhibits low heat release but also shows improved strength development, with a 72-hour compressive strength of 8.05 MPa when cured at 10 °C.

Enhancing marl soil stability: nanosilica’s role in mitigating ettringite formation

Marl soil is highly prone to erosion when exposed to water flow, posing a potential threat to structural stability. The common practice of stabilizing soil involves the addition of cement and lime. However, persistent reports of severe ruptures in many stabilized soils, even after extended periods, have raised concerns. In stabilized marls, unexpected ruptures primarily result from the formation of ettringite, which gradually damages the soil structure. This article aims to assess the impact of nanosilica on the formation of ettringite and the nanostructure of calcium silicate hydrate (C-S-H) during the marl soil stabilization process with lime. To achieve this, marl soil was stabilized with varying percentages of lime and nanosilica. X-ray diffraction (XRD) patterns and scanning electron microscopy (SEM) images were collected to observe changes in mineralogy and microstructural properties. Various geotechnical parameters, including granularity, Atterberg limits, compressive strength, and pH, were measured. The results indicate that the uniform distribution of nanosilica in marl-lime soils enhances pozzolanic activities, calcium aluminate hydrate growth (C-A-H), and the nanostructure of calcium silicate hydrate (C-S-H). According to XRD and SEM experiments, the presence of nanosilica reduces the formation of ettringite. Moreover, the compressive strength of modified samples exhibited an upward trend. In the experimental sample manipulated with 1% nanosilica combined with 6% lime, the compressive strength increased by 1.84 MPa during the initial 7 days, representing an approximately 18-fold improvement compared to the control sample.

Resource utilization of sulfidic copper tailings in calcium aluminate cement: Mechanical property, hydration process and environmental impact

Sulfidic copper tailings (STs) is a byproduct generated from mineral processing activities. To address this environmental burden, calcium aluminate cement (CAC) was used to utilize STs as cementitious materials. The influence of STs on the hydration process, mechanical properties and life-cycle assessment of STs blended CAC were investigated. Results show that the initial setting time of the samples is significantly shortened with the presence of STs. Moreover, the addition of STs greatly accelerates cement hydration and promotes the formation of ettringite, which is caused by the dissolution of sulfidic-rich STs. Hence, the hardened cement paste containing 5 wt.% STs with dense microstructure and high elastic modulus is achieved, which enhances the compressive strength for STs blended CAC. From an environmental point of view, the utilization of STs can save energy and reduce CO2 emissions. Such work may provide new insights into the application of sulfidic copper tailings in low-carbon cementitious materials.

Multi-technique analysis of seawater impact on the performance of calcium sulphoaluminate cement mortar

The construction of offshore islands and reefs requires the development of new seawater sea-sand concrete materials. This study investigated the impact of seawater on the performance of calcium sulphoaluminate (CSA) cement mortar, with mechanism analyses by the acoustic emission (AE) and digital image correlation (DIC). For all uniaxial compression tests, cumulated AE, average AE frequency, rise angle, b-value, and βt coefficient were considered to perform the failure analysis. In addition, other techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) were also employed to highlight the effects of seawater on the hydration products and microstructure of the CSA cement. The results show that seawater not only promotes the formation and growth of ettringite (AFt) but also interacts with cement hydration products to produce Friedel’s salt and various gel formations. Compared to freshwater mixing (0 %), using seawater mixing at normal concentrations (3.3 %) enhances the compactness of the CSA cement, thereby improving the strength and ductility of the CSA mortar. Specifically, the peak load increases from 77 kN to about 86 kN when mixed with seawater at normal concentration, whereas higher seawater concentrations (6.6 %, 9.9 %) resulted in a slight decrease in strength of the CSA mortar, with the peak load reaching approximately 80 kN, yet the ductility is enhanced, as evidenced by the softening post-peak branch of the loading curve. Additionally, AE bursts have a strong correlation with the fracture of the CSA mortar, which can also be forecast by the AE time-scaling coefficient βt. Therefore, when constructing oceanic island and reef foundations, this type of seawater sea-sand concrete is preferred due to its improved ductility and strength, which enhances the structural integrity of marine constructions and provides early warning for effective marine disaster prediction.

Clinker-free cement based on calcined clay, slag, portlandite, anhydrite, and C-S-H seeding: An SCM-based low-carbon cementitious binder approach

A clinker-free cement (CFC) based on portlandite, calcined clay, slag, limestone powder, anhydrite, and C-S-H seeding is reported. The aim was to develop a low-carbon clinker-free cementitious binder using supplementary cementitious materials (SCMs), portlandite, a sulfate source, and accelerators. The impacts of ordinary Portland cement (OPC), portlandite, calcined clay and anhydrite on the strength of the C-S-H-seeded CFC were investigated. Strength, flow, setting and expansion of the mortar were investigated. Hydration kinetics were studied using calorimetry and XRD Rietveld analysis. Results showed that the seeded CFC exhibited similar strength and flow to OPC but produced significantly less heat. The factors contributing to the enhanced strength and improved flow behavior of the CFC were examined. Expansion behavior of CFC and its relationship with anhydrite content and ettringite formation was analyzed. Additionally, the microstructure of the hardened paste was characterized using SEM and mercury intrusion porosimetry (MIP) to evaluate the impact of C-S-H seeding. The combination of a low-carbon binder mix design and C-S-H seeding effectively reduced the CO2 footprint of cementitious binders, with the seeded-CFC achieving >50 % reduction in CO2 emissions per MPa compared to OPC. The proposed CFC binder approach was further validated using other types of SCMs.

Effect of phosphorus impurities on sulfoaluminate cement-modified gypsum-based self-leveling mortar and improvement method

The preparation of gypsum-based self-leveling mortar (GSLM) from solid waste-derived sulfoaluminate cement-modified hemihydrate gypsum is an effective path to enhance its mechanical properties. However, the phosphorus impurities in phosphogypsum (PG) still pose a challenge to the hemihydrate gypsum & sulfoaluminate cement composite system. To evaluate the impact of phosphorus impurities and develop targeted removal strategies, this study first assessed the effects of different types of phosphorus impurities on the mechanical properties and hydration characteristics of the GSLM. Then, a method of pretreating PG with carbide slag (CS) was proposed, and the removal efficiency and mechanism of phosphorus were examined by ICP-OES and XPS testing. The results indicated that the soluble phosphorus impurities severely inhibit the hydration of both CŜH0.5 and C4A3Ŝ, leading to a most notable reduced mechanical performance. The sequence of inhibitory action was as follows: H3PO4 >> Ca(H2PO4)2·H2O > CaHPO4·2H2O > Ca3(PO4)2. CS could effectively immobilize the soluble phosphorus in PG. The pretreatment by CS notably enhanced the hydration degree of the GSLM by converting soluble phosphorus into Ca3(PO4)2 beforehand. In addition, the alkaline environment provided by CS promoted the ettringite formation. When the CS content approaches 3%, a PG-based GSLM with good performances meeting the G20 standard requirements of GSLM can be prepared.

Effect of fly ash on properties and hydration of calcium sulphoaluminate cement-based materials with high water content

Abstract In this study, the effects of fly ash (FA) on the setting time, compressive strength, and hydration evolution of calcium sulphoaluminate (CSA) cement-based materials with high water content were investigated, targeting the design of a modified high-water material to delay excessively rapid setting time and enhance later-age strength. This was investigated using a combination of X-ray diffraction (XRD), Fourier transform infrared resonance (FTIR) spectroscopy, and Thermogravimetric Analysis (TGA). The results showed that the setting time of the high-water materials was delayed by increasing the FA content, with 15% being the optimal dosage for the setting time. A 5–10% content of FA is conducive to the development of later-age compressive strength and has a slight adverse effect on the early-age compressive strength of high-water materials. The microscopic test results show that FA mainly acts as a microaggregate in the early-age hydration process, whereas in the later-age hydration process, it promotes gypsum consumption and C2S hydration to form ettringite. The incorporation of FA effectively promotes ettringite formation in CSA cement-based materials with high water content. Therefore, the addition of FA can enhance the overall performance of high-water materials to a certain extent, and the long-term strength development of the material can satisfy engineering requirements.

Substantially enhanced reaction of steel slag binder stimulated by the addition of sodium sulfate and thermal treatment

An industrial by-product of steel slag has a huge potential as an alternative binder and new supplementary cementitious material (SCM). In both pure steel slag and composite systems, the amount of sulfate can be a critical factor to control early-age performance. This study aims to improve the hydration of steel slag stimulated by using a small amount of Na2SO4. The results showed that 1 % Na2SO4 enhanced both C2(A,F) and C2S hydration, leading to improved strength and denser microstructures with the formation of ettringite, AFm, and siliceous hydrogarnet. Initial thermal treatment at 40 °C with 3 % Na2SO4 provided a fast development of compressive strength at 3 days over 15 MPa. Meanwhile, an excessive amount of alkali supplied by Na2SO4 affects the relative stability between SO4-rich AFm and ettringite and has a detrimental effect on mechanical performance. The result implies that Na2SO4 content should be precisely controlled when used as a stimulator in a composite system with steel slag.

Utilization of industrial waste sodium sulfate for calcined clay-based sustainable binder

This study explored the utilization of industrial waste Na2SO4 to develop a calcined clay-based sustainable cementitious composite inspired by ancient Roman concrete. Na2SO4 with or without the addition of NaCl was utilized, keeping the total Na2O quantity constant, and their performances at the macro and micro scale were compared. A separate set of samples was prepared using seawater. A medium-grade calcined clay, along with lime, was utilized as the binder. The salts were first dissolved in water and then used as the mixing water for sample preparation. A diverse array of characterization methods was utilized, encompassing thermogravimetric analysis, chemical extraction, X-ray diffraction (XRD), and Backscattered Scanning electron microscopy (SEM). It was observed that the salt-containing batches achieved compressive strength faster than the seawater samples. However, the strength remained in a comparable range (∼30 MPa) for all the samples after 28 days of curing. The initial strength of salt-containing samples was attributed to the formation of gypsum, ettringite, and hydrocalumite. Additionally, the geopolymer gel and calcium aluminum silicate hydrate (C-A-S-H) gel phases were present in all samples. Finally, this study also showed that lime-clay mortars can achieve a reduction in carbon footprint of up to 50 % compared to ordinary portland cement (OPC) mortars.

Investigation of the mechanical and durability properties of concrete containing modified fly ash and modified zeolite powder: An effective transport model for sulfate ions in concrete

The application of conventional fly ash and zeolite powder in the field of concrete durability is limited. In this study, durability tests coupling dry-wet cycling and sulfate erosion were conducted on concrete with varying dosages of modified fly ash (MFA) and modified zeolite powder (MZP). The compressive strength, failure mode, water absorption rate, and ion concentration changes were systematically investigated. The reaction products and structure were analyzed through SEM, EDS, and XRD tests, correlating with macroscopic parameters. An effective transport model for sulfate ions in concrete was established, considering the material influence coefficient km and the effective diffusion coefficient De. The results indicate that a higher content of Ca phases in MFA leads to a reduction in concrete early strength, while later stages exhibit rapid strength growth due to pozzolanic reactions. MZP contains a significant amount of Al and Si phases, which promote both early and later-stage concrete strength. MFA and MZP enhance the resistance of concrete to sulfate erosion, with MZP exhibiting a significantly superior improvement effect compared to MFA. This is attributed to the following factors: on the one hand, the addition of MFA and MZP reduces the porosity and improves the pore structure of concrete, thus delaying the diffusion of sulfate ions into the concrete; on the other hand, the pozzolanic reactions of MFA and MZP consume available calcium hydroxide, leading to the formation of C–S–H and C-A-S-H gels, which densify the microstructure and reduce the probability of leaching erosion of hydration products, thereby limiting the formation of ettringite. The applicability and reliability of the sulfate-ion effective transport model were verified based on experimental data. The model can be employed to predict the distribution of sulfate ions in different types of concrete under various erosion durations, reducing workload and providing a theoretical basis for the durability design and service life prediction of concrete structures in sulfate environments.

Enhancement of phosphogypsum-based solid waste cementitious materials via seawater and metakaolin synergy: Strength, microstructure, and environmental benefits

Phosphogypsum-based cementitious materials (PGCM) possess the potential to solidify corrosive ions in seawater and may serve as a viable alternative to Ordinary Portland Cement (OPC). However, despite this potential, limited research has explored the use of seawater as mixing water in PGCM, and the hydration mechanism underlying their interaction remains unclear. This study aimed to examine the impact of seawater on the macroscopic and microscopic characteristics of PGCM, as well as the underlying mechanisms and the evolution of PGCM properties in the presence of a synergistic effect between seawater and supplementary cementitious material, metakaolin (MK). The results demonstrate that using seawater as mixing water for PGCM mortars reduces workability. Conversely, sulphate ions in seawater shortened the induction period of PGCM, accelerated ettringite formation, shortened the setting time of PGCM, and enhanced the early strength of PGCM. However, the enhancement of the late strength of PGCM by seawater was limited. The synergistic effect of seawater and MK significantly increased the compressive strength of PGCM, with an enhancement of 45.31% and 20.48% at 28 and 90 days, respectively. This enhancement was linked to the hydration reaction of Na+ ions in seawater and MK, forming N-A-S-H gel network structure that influenced the microstructure of PGCM. Moreover, the incorporation of seawater and MK in PGCM offers both economic and environmental sustainability benefits.

Mineral carbonation performance of wollastonite-blended cementitious composites through in-situ CO2 mixing

This study assessed the feasibility of in-situ CO2 mixing in a wollastonite-blended cementitious composite by evaluating its mineral carbonation performance. Wollastonite (CS) polymorphs were synthesized and used to replace ordinary Portland cement with up to 30 wt%. The results showed that amorphous CaCO3, calcite, and monocarboaluminate were formed as carbonation products. The wollastonite-blended cementitious composite with a 20 % replacement of β-CS exhibited the highest CaCO3 production of 22.5 wt%, which was mainly attributed to amorphous CaCO3. β-CS showed a superior mineral carbonation ability to α-CS because the Ca-depleted silicate layer formed by the dissolution of β-CS accelerated the formation of amorphous CaCO3. Moreover, CS retarded the early-stage formation of ettringite and monocarboaluminate by delaying gypsum dissolution. The wollastonite-blended cementitious composites exhibited superior compressive strength exceeding 40 MPa. These results demonstrate that the mineral carbonation of wollastonite-blended cementitious composite can be accomplished through in-situ CO2 mixing, especially with β-CS replacement, which has significant potential as a CO2 storable binder.

A coupled chemo-transport-mechanical damage model for the mineral transformation in cementitious materials under a sulfate-rich environment

The present study proposes a coupled chemo-transport-mechanical damage model integrating thermodynamics, fluid-solid transformation, and mechanical damage modeling to predict the physicochemical characteristics of cementitious materials under a sulfate-rich environment. For verifying the proposed model, calcium sulfoaluminate (CSA) cements with various molar ratios of calcium sulfate over ye'elimite (m-values) were adopted for a case study. The thermodynamics model for the phase assemblage of CSA cements with various m-values under a sulfate-rich environment is compared with the experimental outcomes. The model parameters in the fluid-solid transformation and mechanical damage models are fitted through the available experimental data in the literature. Mineral compositions, crystallization pressure, effective elastic modulus, delayed ettringite formation, and microcracks of CSA cement pastes were modeled by a proposed coupled chemo-transport-mechanical damage model, with model parameters fitted to experimental data, thereby assessing the applicability of the proposed model. The predicted results show that an increase in m-value of the samples increases the rate of sulfate ion penetration and crystallization pressures. Moreover, DEF, microcrack evolution, and mechanical degradation can be attributed to the amount of ye'elimite and hydrated monosulfate of the samples.

Hydration of a 2-component CSA-OPC-mix – timing of component blending & setting on demand

With the ongoing development of new technologies like 3D printing, the requirements for the performance of cementitious materials become more complex. Setting on demand, while the workability of the material is retained until placement, is an important aspect of this usage. A ternary CSA-OPC-C$ system was developed to achieve setting on demand in a 2-component setup, where two retarded cementitious components were mixed after specific times of storage. The kinetics of the individual systems and the blend were examined by heat flow calorimetry, quantitative X-ray diffraction and pore water analysis. The rheological development was monitored by a penetration test method. The results show that the performance of the blend is independent of the storage time of the individual components and can be tailored by changes in the retarder dosage in the individual components. The initial reaction in the blend is characterized by the simultaneous dissolution of ye'elimite and C3S, resulting in the formation of ettringite as the sole detectable hydrate phase. The fate of silicon remains unclear as with the methodology at hand no silicon incorporating hydrate phase can be identified.

Hybrid alkali-activated fly ash-Portland cement binders with modified polymer as patch repair

The alternative patch repair derived from hybrid alkali-activated binders (HAAB) were investigated in this paper. The HAAB mortar was produced with fly ash (FA), Portland cement (PC), and polymer-modified material (PMM). The additives (PC and PMMs) were used to replace FA at the dosage of 30 % by weight of binder. The proportions of PC-to-PMM at 30:0, 20:10, 10:20, and 0:30 were investigated. Sodium silicate (NS) and sodium hydroxide (NH) solutions were used as the alkaline activators. Constant NS-to-NH ratio of 2.0 and liquid/solid binder ratio of 0.60 were used for all mixtures. Experimental results showed that the setting time, compressive and shear bond strengths of the HAAB mortars met the requirement for repair material as specified by ASTM standard. The 7-day bond strength increased with increasing PMM replacement up to an optimum level; thereafter, it started to decline. A combination of PC and PMM in FA-based HAAB enhanced the adhesion at contact zone. Moreover, the HAAB mortars showed greater durability compared to conventional PMMs after immersion in sulfate and acid solutions, as evidenced by its relatively low strength loss. The increased formation of ettringite might be the main factor for the substantial reduction in the strength of PMM mixes. Therefore, the HAAB mortar is an attractive choice for patch repair material in terms of excellent durability, high bond strength, cost-effectiveness, and low carbon footprint compared to conventional PMM.

Influence of weak acid salts and curing condition on supersulfated cement mortar

This study explores the impact of weak acid salt agents (citrate and tartrate) in the mixture and various curing conditions on the properties of supersulfated cement (SSC) mortar. Compressive strength tests were conducted on prism-shaped samples measuring 4 × 4 × 16 cm. A comprehensive analysis of the phase assemblage of hardened products was carried out using X-ray diffraction (XRD), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS). The results reveal the abundant formation of ettringite (E) and hydrotalcite (Ht) when weak acid salt agents are added, especially in chloride and sulfate-rich curing solutions, leading to a notable increase in compressive strength, up to 200% compared to the control sample. Furthermore, the study demonstrates a substantial improvement in early and overall strength under temperature-stimulated curing conditions, accelerating the hydration reaction of SSC. These findings provide deeper insights into the factors influencing SSC hardening and strength development, offering valuable information for enhancing the efficiency and utilization of SSC in the construction industry, aligning with the goals of sustainable development.

Nano-fly ash and clay for 3D-Printing concrete buildings: A fundamental study of rheological, mechanical and microstructural properties

Three-dimensional printing concrete (3DPC) represents a recent innovation in the construction and building research sector and novel approach to building techniques. The focus of this study is to develop an environmentally sustainable cementitious composite optimized for 3D printing applications. The research involved preparing 3D printing mixtures that comprised of 50 % Portland Cement (PC), 50 % Colorobia Clay (CC), and varying contents (0 % 5 %, 10 %, and 15 % by weight of cement) of Nano-Fly Ash (N-FA) under standardized printing parameters. The fresh mixture's properties have been evaluated and the mechanical and microstructural properties of the printed samples were assessed, subsequently. The findings demonstrated that incorporating N-FA into the cementitious mixes enhanced their flowability and workability. Specifically, the mix containing a low N-FA concentration of 5 wt% exhibited superior compressive strength relative to the other formulations. Additionally, flexural strength assessments indicated a minimum increase of 39.4 % across all mixes compared to the control 3D-printed mixture. Microstructural investigations by SEM imaging validated the anticipated formation of hydration products, namely calcium-silicate-hydrate (CSH) and ettringite, facilitated by the synergy between clay and fly ash. The t-statistical analysis further corroborated that the inclusion of N-FA significantly bolstered the strength attributes of the mixes designated for 3D printing. In conclusion, this study underscored the efficacy of integrating clay as a sustainable construction material within 3D printing applications. The utilization of clay-cement mixes, augmented with N-FA, emerged as a viable strategy to enhance the sustainability and reduce the carbon footprint of construction practices.