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Article

Influence of Slag/Fly Ash as Partial Cement Replacement on Printability and Mechanical Properties of 3D-Printed Concrete

by
Kuo-Chang Tseng
1,
Maochieh Chi
2,*,
Weichung Yeih
1 and
Ran Huang
1
1
Department of Harbor and River Engineering, National Taiwan Ocean University, Keelung City 20224, Taiwan
2
Department of Civil Engineering and Engineering Management, National Quemoy University, No. 1, Daxue Road, Jinning 89250, Taiwan
*
Author to whom correspondence should be addressed.
Appl. Sci. 2025, 15(7), 3933; https://doi.org/10.3390/app15073933
Submission received: 15 January 2025 / Revised: 20 March 2025 / Accepted: 27 March 2025 / Published: 3 April 2025
(This article belongs to the Section Civil Engineering)
Browse Figures
Versions Notes

Abstract

Three-dimensional printing is an emerging technique that has received significant attention in the construction industry. This study presents an investigation into the printing and hardened properties of 3D-printed concrete (3DPC). Both fly ash (FA) and ground granulated blast furnace slag (GGBFS) were used to replace cement in different ratios (0%, 25%, and 50%) to produce 3DPC. Extrudability and buildability tests were performed to evaluate the effects of FA and GGBFS in various proportions on the printing properties of 3DPC. Additionally, the hardened properties of 3DPC were determined. Test results show that all mix designs meet the printing requirements of 3DPC. The specimens with a higher proportion of GGBFS exhibited higher unit weight and compressive and flexural strength, but lower water absorption and drying shrinkage. The compressive and flexural strength of 3DPC in the printing direction were the highest, outperforming those of the cast specimens at the age of 28 days. Our results indicate that FA and GGBFS can be used to replace 50% of the cement in 3DPC.

1. Introduction

Three-dimensionally printed concrete (3DPC) is an emerging technology that has garnered significant attention within the construction industry due to its potential for revolutionizing the building process. Unlike conventional casting methods, the 3D printing of concrete enables automated, layer-by-layer construction without the need for formwork, thereby reducing material waste, labor costs, and construction time. However, to achieve optimal performance in 3D printing, concrete mixtures must exhibit specific rheological properties, such as extrudability, buildability, and workability, while maintaining sufficient mechanical strength in the hardened state [1,2,3,4,5,6,7,8]. Traditional formwork often necessitates extensive labor and a significant variety of materials, making 3DPC an attractive alternative in terms of efficiency and sustainability. One of the critical challenges with 3DPC is ensuring that the concrete develops adequate early-age strength to maintain the desired shape during the layer stacking process, a characteristic referred to as buildability [9,10]. Additionally, concrete needs to be fluid during the pumping process, so the rheological properties in the early stages of 3DPC are very important [11,12]. In this novel concrete printing process, printability is defined as the property determining the printable performance of a cementitious mixture. Finally, 3DPC is completely different from traditional concrete in rheology and mechanical performance [13,14,15]. Thus, it is essential to develop appropriate 3D-printing materials.
In contrast to traditional concrete, 3DPC produced without formwork is designed to have low- or no-slump characteristics [16,17,18]. This results in adequate stiffness to preserve the stability of the printed shapes. Given the distinctions between traditional construction methods and this new concrete printing technique, it is crucial to take into account the fresh properties of 3DPC in relation to the innovative nature of the printing process.
Ordinary Portland cement (PC) is typically the principal cementitious material used in 3DPC, constituting approximately 15–45% of the total mix [19]. The content of cement in 3DPC is higher than that in traditional concrete [20]. However, the increase in the amount of PC may lead to higher material costs and severe environmental impact [21]. As sustainability concerns grow, researchers have explored the partial replacement of cement with supplementary cementitious materials (SCMs), such as fly ash (FA) and ground granulated blast furnace slag (GGBFS). These industrial by-products not only improve the sustainability of concrete but also enhance its mechanical and durability properties [22,23]. FA is known to improve workability and reduce the heat of hydration, which enhances fresh concrete’s pumpability and buildability. Similarly, GGBFS has demonstrated the ability to improve buildability due to its finer particle size and latent hydraulic properties, which can also lead to reduced cracking during the extrusion process [24]. However, both materials affect hardened properties differently: FA generally contributes to long-term strength gain due to pozzolanic reactions, while GGBFS often enhances early-age strength and overall durability [25,26,27]. Previous studies have demonstrated that incorporating these materials can positively affect both fresh and hardened concrete properties, but their impact on 3DPC remains an area of active research.
Given the unique requirements of 3DPC, including the balance among pumpability, shape stability, and strength, understanding the effects of FA and GGBFS replacement on these properties is crucial. While some studies have explored SCMs in 3DPC, there remains a need for comprehensive research on how different replacement ratios influence both fresh and hardened properties. According to research trends, there has been a focus on incorporating industrial by-products to reduce reliance on cement while minimizing waste and environmental impact [28]. Taqa et al. [29] found that the inclusion of nano-fly ash (N-FA) significantly increased the strength of the mix design for 3D printing. Guo et al. [30] developed a 3D-printing mix design with fly ash (FA) and quartz sand as the main raw materials, using ground granulated blast furnace slag (GGBFS) and silica fume (SF) as supplementary cementitious materials. Li et al. [31] used GGBFS to produce 3D-printing materials. Yu et al. [32] pointed out that using up to 10% steel slag (SS) improves the buildability of 3DPC. However, the rheological properties of 3DPC decrease when the content of SS is more than 20%. Ma et al. [33] synthesized a new type of 3D-printable geopolymer with FA, GGBFS, SS, and flue gas desulfurization gypsum (FGD), further highlighting the potential of alternative materials.
Despite these advancements, a significant gap remains in the establishment of national or regulatory codes to scrutinize and regulate the short- and long-term performance of 3DPC materials. Thus, ongoing research is vital to bridging this divide. In this study, the effects of FA and GGBFS as partial cement replacements (0%, 25%, and 50%) on the extrudability, buildability, and hardened properties of 3DPC were investigated. The novelty of this work lies in evaluating not only the printability of the mixtures but also their mechanical performance in the printing direction compared with conventionally cast specimens. The findings provide insights into the potential of FA and GGBFS to enhance the sustainability and performance of 3DPC while maintaining its structural integrity [34].

2. Experimental Program

2.1. Materials

Type I ordinary Portland cement conforming to ASTM C150-07 [35], and the pozzolanic materials ground granulated blast furnace slag (CHC Resources Corporation, Kaohsiung, Taiwan) and class F fly ash (Xingda Power Plant, Kaohsiung, Taiwan), were used as the main cementitious materials in this study. Their physical properties and chemical composition are listed in Table 1 and Table 2, respectively.
From Table 2, it can be seen that the main chemical composition of GGBFS was 40.53% CaO and 33.59% SiO2, and that fly ash contained 56.48% SiO2 and 20.34% Al2O3. In this study, anhydrous sodium silicate powder (Na2SiO3) with purity greater than 99% purchased from Shin-shin chemical company in Taiwan, and RHEOPLUS-411 polycarboxylic acid superplasticizer (PCE) with a density of 1120 kg/m3 obtained from BASF company in Germany were selected as the additives; their physical properties are listed in Table 3. River sand was used as a fine aggregate in the manufacture of mortars. The specific gravity, bulk density, absorption, and fineness modulus of the fine aggregate were 2.57, 2523 kg/m3, 2.93%, and 1.97, respectively. The sieve analysis and grading curve of the fine aggregate are given in Table 4 and Figure 1, respectively.

2.2. Mix Design and Specimen Preparation

In this study, ground granulated blast furnace slag (GGBFS) and fly ash (FA) were used to replace 25% or 50% of cement. Although higher replacement levels might result in decreased mechanical performance, the properties of the 50% replacement mix are still within acceptable limits for specific applications. Moreover, anhydrous sodium silicate powder at 5% by mass of binder and 0.5% PCE were used in the investigation on the development of 3D-printed concrete. Both the water-to-binder ratio and the sand-to-binder ratio were kept constant at 0.4 and 1.5, respectively. GGBFS and FA, denoted by “S” and “F”, for cement replacement at 0%, 25%, and 50%, denoted by “0”, “25”, and “5”, were used for the specimens. The mortar mix proportions are summarized in Table 5. The mix design was divided into two parts: the first part involved specimen casting, and the second part involved specimen 3D printing. The purpose of the experiment was to evaluate the differences in mechanical properties, durability, and overall performance between traditional concrete specimens and 3DPC specimens. By comparing these two methods using the same mix design, in this study, we aimed to assess the feasibility, advantages, and potential limitations of 3DPC in construction applications.
The method for preparing the cast specimens followed the mixing procedure specified in CNS 1010 [36]. The specimens were kept in steel molds for 24 h; then, the specimens were demolded and moved into a curing room at a relative humidity of 80% RH and a temperature of 25 °C until testing. Three specimens were tested for each mix design. The mixing procedure for the 3D-printed mortars is described as follows: First, we dry-mixed PC, GGBFS, FA, sand, and anhydrous sodium silicate powder for 1 min. Then, we added water and 50% of PCE and continued mixing for approximately 3 min. Afterwards, we let the mixture rest for 10 min. We added the remaining 50% of the PCE and mixed at medium speed for 1 min to complete fresh mortar mixing. We manually transferred the fresh mortar into 3D-printing equipment. Then, we started the 3D printer to fill the nozzle with fresh mortar and adjusted the printing flow rate and speed. Once the printing conditions were stable, we proceeded with the 3D printing of the specimens needed. A picture of the printing process is shown in Figure 2. The 3D-printed specimens were cured for 28 days at a relative humidity of 80% RH and a temperature of 25 °C.

2.3. Test Methods

The mechanical equipment used for producing 3DPC was a gantry-type 3D printer that included a 3D-printing material cylinder, an extrusion screw, a circular nozzle, and a movable printing platform. The maximum printing dimensions were 600 × 600 × 700 mm, with a repeatability of ±0.05 mm, and it supported G-code file formats.
Printing parameters such as printing speed and layer height significantly influence the printability and final performance of 3DPC. Higher printing speeds can reduce interlayer bonding, affecting mechanical strength, while lower speeds may cause deformation due to prolonged material flow. Similarly, layer height impacts buildability and structural integrity, where excessive height can lead to instability and insufficient height may affect extrusion consistency. In this study, a 15 mm diameter nozzle was used, with an extrusion flow rate of 7–10 cm3/s and an extrusion ratio of 1900–2000. The printing path speed was set to 35–40 mm/s using Prusa Slicer (https://prusaslicer.net/, accessed on 26 March 2025), with a single-layer height of 10 mm.
In this study, we conducted tests on the printable and hardened properties of 3DPC. Each experiment on the printable properties, including flowability, slump, extrudability, and buildability, was repeated twice, and the values were averaged. If there was a significant difference between the two results, the experiment was repeated to ensure the consistency of the experimental results. For the experiments on the hardened properties, including unit weight, compressive strength, flexural strength, water absorption, and drying shrinkage, three specimens of each mixture were tested to determine the average results.

2.3.1. Slump Flow Test

Slump flow is an important indicator of the ability of cement paste to flow under its own weight, reflecting the pumpability and workability of the paste. In this study, flowability tests were conducted according to ASTM C1611 [37] to investigate the flow characteristics of the mortars.

2.3.2. Slump Test

The slump test was conducted in accordance with ASTM C94 [38], but the slump mold used was a reduced-scale mold with a height of 150 mm, an upper circular diameter of 50 mm, and a base diameter of 100 mm, because only mortar materials could be used in our 3D printer. This size of mold is suitable for small test samples and provides the ability to accurately evaluate concrete flow properties.

2.3.3. Extrudability Test

Extrudability is the criterion used to evaluate whether a fresh mix can smoothly pass through the print head of a 3D printer and extrude a continuous, unbroken printing strip. A square-shaped test strip with a length and width of 400 mm was used to evaluate the extrudability of each mix. If no material breakage occurred during the printing process, the mix was considered extrudable, as shown in Figure 3.

2.3.4. Buildability Test

Test specimens with dimensions of 220 mm × 120 mm × 150 mm were printed to evaluate the buildability of the fresh mixes. If no tipping or collapse of the specimen occurred during the printing process, the tilt angle and height difference of the specimen were measured, as shown in Figure 4. If the tilt angle was not greater than 2 degrees and the height difference was within 5%, the mix was considered buildable.
The calculation method for the tilt angle and height difference of the specimens is as follows: Measure the widths of the specimen at the top and bottom layers (B15: the width of the specimen at the top layer; B1: the width of the specimen at the bottom layer), as well as the actual height of the specimen (Ha). Then, calculate the tilt angle (ΔB) and height difference values (ΔH) using the following formulas:
Tilt   angle   formula   ( degree ) :   Δ B = T a n − 1 B 15 − B 1 2 H a
Height   difference   formula   ( % ) :   Δ H = H t − H a H t × 100 %
where Ht is the target height of the specimen.

2.3.5. Unit Weight Test

The measurement of the unit weight of the cast specimens was conducted according to ASTM D854 [39].

2.3.6. Compressive Strength Test

The compressive strength test of the specimens was conducted according to ASTM C109 [40]. For the cast specimens, 50 × 50 × 50 mm3 cubes were prepared, and three specimens of each mixture were tested at 28 days to determine the average compressive strength. For the 3DPC specimens, 60 × 60 × 220 mm3 rectangular cuboids were printed, as shown in Figure 5. During the printing process, the 3DPC specimens were layered, making them anisotropic materials with varying strength in different directions. After removing the corners on both sides of the 3D-printed concrete specimens with a cutting machine, we cut the specimens into three pieces, each piece with dimensions of 60 × 60 × 60 mm3. Then, the compressive strength tests of the 3D-printed concrete specimens were conducted in the X, Y, and Z directions at the curing ages of 7, 14, 21, and 28 days to compare their strength values in different directions with those of the cast specimens. The schematic diagram of the 3D-printed specimens’ compressive strength in the X, Y, and Z directions is given in Figure 5.

2.3.7. Flexural Strength Test

This test method was used to determine the flexural strength of the specimens prepared and cured in accordance with ASTM C78 [41]. Each group of flexural strength specimens consisted of both 3DPC specimens and cast specimens. The 3DPC specimens were directly printed in a rectangular shape measuring 60 × 60 × 220 mm3, while the cast specimens were prepared as 40 × 40 × 180 mm3 cubes. Twenty-four hours after the specimens were produced, they were placed in water for curing at the age of 28 days. The flexural strength of the 3DPC specimens in the printing direction was measured. Three specimens of each mixture were tested to determine the average flexural strength.

2.3.8. Water Absorption Test

The water absorption test was conducted in accordance with ASTM C642 [42]. The cast specimens, in the shape of 50 × 50 × 50 mm3 cubes, were tested at the age of 28 days to determine the average water absorption.

2.3.9. Drying Shrinkage Test

The drying shrinkage test was performed in accordance with ASTM C596 [43]. Prismatic specimens with 285 × 25 × 25 mm3 dimensions were prepared and then demolded the day after. The initial length (Li) of the shrinkage specimens was measured on day 1; then, the specimens were placed in a humidity cabinet at 80% RH and a temperature of 25 °C. The length (Lx) of the shrinkage specimens was measured at the ages of 3, 7, 14, 21, and 28 days. The length change (drying shrinkage) was then calculated with the following formula:
Drying shrinkage: LC (%) = (Li − Lx)/G × 100%
where G is the nominal effective length.

3. Results and Discussion

3.1. Slump Flow

Flowability is an important indicator of the ability of cement paste to flow under its own weight, reflecting the pumpability and workability of the paste [44]. The flowability and slump of the tested mortars are listed in Table 6. It can be seen that the order of the flowability values is S0F5 > SF25 > S5F0. When only FA is used to replace cement, the highest flowability, 118%, is achieved; when both FA and GGBFS are used to replace cement, the flowability slightly decreases; finally, when only GGBFS is used to replace cement, the flowability decreases to 105%. This indicates that adding FA to cement mortar provides higher flowability, while adding GGBFS reduces the original flowability of the cement mortar. The particle shape and size of GGBFS are usually irregular and rough, which increases internal friction and thus reduces flowability. On the other hand, the particles of FA are typically spherical and smooth, which reduces internal friction and increases flowability. Additionally, GGBFS generally has higher particle density and specific surface area, allowing it to absorb more water and reduce the amount of free water in the mortar, thereby decreasing flowability. In contrast, FA has lower particle density and specific surface area, absorbs less water, and increases the amount of free water in the mortar, thus enhancing flowability. This result is consistent with that obtained by Rushing et al. [45].

3.2. Slump

From Table 6, it can be seen that the order of the slump values is S0F5 > SF25 > S5F0. The slump of mortar decreases from 5.9 cm to 4.4 cm with a decrease in FA cement replacement of 50% to 0%. The reason is the same as previously mentioned in Section 3.1.

3.3. Extrudability

Extrudability is solely based on the flowability of printed concrete [16]. In this study, a 3D printer was used to print square frames with dimensions of 400 mm × 400 mm × 10 mm to determine whether the mortars could be successfully extruded, thereby assessing the printability of the materials. The test results are shown in Figure 6. It can be seen that the square frames printed with the three mix designs were continuous, with no occurrences of breakage nor air bubbles. This indicates that all three mix designs meet the extrusion standards for 3DPC. Hambach and Volkmer [46] reported that the addition of a water-reducing admixture ensures smooth and continuous extrusion. In this study, 0.5% PCE was used to achieve better extrudability. The extrudability of the specimens was influenced by the distinct properties of FA and GGBFS. FA enhances workability due to its spherical particle shape, which reduces friction and improves flowability, making the mix easier to extrude. In contrast, GGBFS contributes to the mix’s cohesion and stability due to its finer particle size and latent hydraulic reactivity, which together help the extruded material retain its shape immediately after extrusion. The combination of these materials ensures a balance between flowability and buildability, making the mixes suitable for 3D-printing applications.

3.4. Buildability

Buildability denotes a printed material’s ability to withstand deformation when subjected to a load [47]. Without formwork, freshly mixed materials need to possess adequate buildability to provide sufficient stiffness after extrusion. This stiffness is essential to supporting the material’s own weight, the load of any upper layers, and the pressure derived from the extrusion process [48]. In this study, rectangular specimens with dimensions of 220 mm × 120 mm × 150 mm were printed to evaluate the buildability of each mix design. The test results are shown in Table 7 and Figure 7. From Table 7, it can be observed that the specimens printed with all three mix designs were stackable up to 15 layers, with no significant collapse or distortion. The height and tilt angle caused by the material’s weight and the extrusion pressure were less than 0.5 cm and 2 degrees, respectively. Therefore, all three 3DPC designs in this study meet the buildability standards. Panda and Tan [16] indicated that the addition of GGBFS leads to better buildability of 3DPC. In this study, the inclusion of FA and GGBFS positively impacted buildability by improving the cohesion and stability of the mix, helping the extruded material maintain its form between layers. FA, with its spherical particle shape, helps reduce the material’s tendency to sag or collapse after extrusion, while GGBFS improves the overall structural integrity of the mix.

3.5. Unit Weight

The unit weight results are shown in Figure 8. It can be seen that the unit weights of the specimens follow the order of S5F0 > SF25 > S0F5. When only FA was used to replace 50% of cement (S0F5), the unit weight was 1869 kg/m3; when both FA and GGBFS were each used to replace 25% of cement (SF25), the unit weight increased to 1885 kg/m3; finally, when FA was not used and only GGBFS was used to replace 50% of cement (S5F0), the unit weight reached the highest value, 1932 kg/m3. The higher the content of GGBFS, the more the unit weight of the specimen increases. This is because the specific gravity of GGBFS is greater than that of FA, so a higher content of GGBFS increases the overall density and unit weight of the specimen.

3.6. Compressive Strength

Compressive strength tests were performed on the 3DPC specimens in three loading directions, i.e., perpendicular, longitudinal, and lateral directions [45]. The compressive strength of S0F5, SF25, and S5F0 in the X, Y, and Z directions at different ages are shown in Figure 9, Figure 10, Figure 11, Figure 12, Figure 13 and Figure 14. It can be seen that the compressive strength of all specimens increased with age. Figure 9, Figure 10 and Figure 11 show that the compressive strength values of different mix designs follow the order of S5F0 > SF25 > S0F5. This indicates that compressive strength increases with the increase in the amount of GGBFS cement replacement. The reason is that GGBFS significantly improves the early and long-term strength of cement-based materials, while FA mainly enhances long-term strength.
The literature reveals that the direction of loading has a strong influence on the compressive strength of 3DPC due to anisotropy [49]. For each group of specimens (S0F5, SF25, and S5F0), the compressive strength values in different directions followed the order of X direction > Z direction > Y direction, as shown in Figure 12, Figure 13 and Figure 14. Paul et al. pointed out that the printing direction may have a significant influence on the overall load bearing capacity of 3DPC [50]. The load in the X direction of the printed specimen is parallel to the interface between strips and layers. When the specimen is damaged, cracks generally extend in the printing direction, making the specimens behave as multiple columns bound together under a load. The load in the Y direction of the printed specimen is parallel to the interface between layers but perpendicular to the interface between strips. During failure, the crack extension direction often exhibits a conical fracture pattern. The load in the Z direction of the printed specimen is parallel to the interface between strips but perpendicular to the interface between layers, resulting in a similar conical fracture pattern during failure to that observed in the Y direction. Therefore, the bonding between layers in the X and Z directions is better, while the interlayer bonding in the Y direction is weaker. In addition, the material deposition in the X and Z directions is more uniform, resulting in higher density. Additionally, stress concentration and crack propagation are more significant in the Y direction, leading to lower strength. These results are consistent with most of the previous works [49,50,51,52]. However, according to Hambach and Volkmer [46] and Zhang et al. [53], there is a significant reduction in compressive strength when measured in the longitudinal direction compared with the perpendicular direction. In addition, findings in Panda et al. [16] reveal that printed samples exhibit their lowest strength along the longitudinal direction and their highest strength in the lateral direction. These conflicting results highlight the necessity for further research and more comprehensive experimental data, as well as a better understanding of the mechanisms influencing compressive behavior across various testing directions. Figure 15 shows the compressive strength of the 3DPC and cast specimens at the age of 28 days. Figure 16 shows the failure mode of the compressive strength test 3DPC and cast specimens at the age of 28 days.
The compressive strength of the cast specimens is a key indicator of the material’s structural integrity and its suitability for applications in construction, including 3D printing. The inclusion of FA generally resulted in a decrease in compressive strength at early ages due to its delayed pozzolanic reactivity. However, GGBFS, with its finely ground particles and latent hydraulic properties, contributed to higher early-age strength than FA. The combination of FA and GGBFS showed balanced performance, with moderate reductions in early compressive strength but overall enhancements in long-term durability and strength. These results indicate that the proposed mix designs are suitable for applications requiring both short-term and long-term performance, though mix design adjustments may be necessary depending on specific requirements. In this study, the compressive strength of the cast specimens was lower than that in the X direction of the 3DPC specimens at the age of 28 days.

3.7. Flexural Strength

In 3DPC, flexural strength, similar to compressive strength, is influenced by the loading direction due to the anisotropic properties introduced by the printing process. There are three directions for examining the anisotropic flexural strength of printed prisms. However, in this study, we focused on only one direction, prioritizing the loading direction typically associated with the highest flexural strength [52]. The flexural strength test results of specimens S0F5, SF25, and S5F0 at the ages of 28 days are shown in Figure 17. It can be seen that the flexural strength of the 3DPC specimens in the X direction is higher than that of the cast specimens and that it increases with the increase in the amount of GGBFS cement replacement. This trend is consistent with the results of the compressive strength tests and those of previous research by Sanjayan et al. [49]. The reason is the same as mentioned above. When the load is parallel to the interface between strips and layers, cracks extend in the printing direction, such that the specimen behaves as multiple columns bound together under a load. Figure 18 shows the failure mode of the flexural strength test specimens, including the 3D printed prisms and the molded specimens, at the age of 28 days.

3.8. Water Absorption

From Figure 19, it can be seen that the order of the water absorption values is S0F5 > SF25 > S5F0. The water absorption of the mortars decreases from 12.94% to 7.56% with the decrease in FA cement replacement from 50% to 0%. In this study, the GGBFS used had a higher specific surface area than the FA. The more GGBFS was added, the higher the density of the specimens was, thus reducing water absorption.

3.9. Drying Shrinkage

Shrinkage plays a critical role in the long-term dimensional stability of structures and their susceptibility to cracking. Research indicates [54,55] that this property is influenced by the volume of hydrated cement paste and the restraining effect of aggregates. Notably, 3DPC differs from traditional concrete in that it utilizes formwork-free construction techniques, leading to an increased surface area of concrete exposed to air, which is more likely to cause concrete drying shrinkage. In this study, three specimens for each mix design were tested to investigate the influence of different amounts of FA and GGBFS cement replacement on the drying shrinkage of 3DPC. The test results are shown in Figure 20.
As can be seen, the 3DPC specimens with a larger amount of FA cement replacement had higher drying shrinkage, with a water-to-binder ratio of 0.4 and a sand-to-binder ratio of 1.5. Specimen S0F5 showed the most significant change, with a drying shrinkage of 0.034% at the age of 28 days. In contrast, the other two 3DPC specimens, SF25 and S5F0, had similar drying shrinkage, 0.025% and 0.0235%, respectively, at the age of 28 days. FA typically increases shrinkage due to its finer particles and slower pozzolanic reaction, which can lead to increased porosity and delayed hydration. The greater difference observed with 50% FA replacement suggests that there exists a threshold where these effects become more pronounced, whereas with 25% replacement, the balance between FA and PC likely mitigates significant shrinkage differences.
The FA used in this study had a finer texture compared with the GGBFS; thus, the 50% FA replacement in S0F5 resulted in relatively lower density compared with the other two specimens (SF25 and S5F0), which contained larger amounts of GGBFS. Consequently, S0F5 was better at absorbing excess moisture within the 3DPC paste, leading to higher water absorption and more pronounced drying shrinkage.

4. Conclusions

Three-dimensional printing technology offers notable advantages over traditional casting methods in construction applications. However, advancing this technology requires interdisciplinary researchers to develop efficient printing systems, innovative design approaches, and materials tailored for 3D printing. A key focus should be on creating materials with suitable rheological properties to ensure satisfactory performance under both fresh and hardened conditions. In this study, we investigated the effects of partial cement replacement with FA and GGBFS on the fresh and hardened properties of 3DPC. The key findings are as follows:
(1)
Flowability and printability: The workability values of 3DPC, assessed based on flowability and slump, follow the order S0F5 > S25F25 > S5F0, indicating that higher FA content enhances flowability. Despite these variations, all mix designs demonstrated sufficient extrudability and buildability, meeting the essential printability criteria for 3DPC.
(2)
Mechanical and durability performance: The specimens with a higher proportion of GGBFS exhibited superior mechanical properties, including higher unit weight, compressive strength, and flexural strength, while demonstrating lower water absorption and reduced drying shrinkage. This suggests that GGBFS contributes to enhanced material densification and long-term durability in 3DPC.
(3)
Anisotropic strength behavior: The compressive strength of 3DPC varied with the printing direction, following the trend X direction > Z direction > Y direction. Notably, the compressive and flexural strength in the X direction exceeded those of the conventionally cast specimens at 28 days, highlighting the structural integrity and potential advantages of the layered deposition process in 3DPC.
These findings emphasize the viability of replacing up to 50% of PC with FA and GGBFS in 3DPC while maintaining high printability and mechanical performance. This study provides novel insights into the anisotropic behavior of 3DPC and the role of SCMs in optimizing fresh and hardened properties, paving the way for more sustainable and structurally efficient 3D-printed construction materials.

Author Contributions

Conceptualization, M.C.; Methodology, K.-C.T., M.C. and W.Y.; Formal analysis, W.Y.; Investigation, K.-C.T.; Writing—original draft, K.-C.T.; Writing—review & editing, M.C., W.Y. and R.H.; Supervision, R.H. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the Ministry of Science and Technology grant number MOST 110-2221-E-507-010-MY3.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The original contributions presented in this study are included in the article. Further inquiries can be directed to the corresponding author.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Pasupathy, K.; Ramakrishnan, S.; Sanjayan, J. 3D concrete printing of eco-friendly geopolymer containing brick waste. Cem. Concr. Compos. 2023, 138, 104943. [Google Scholar]
  2. Liu, D.; Zhang, Z.; Zhang, X.; Chen, Z. 3D printing concrete structures: State of the art, challenges, and opportunities. Constr. Build. Mater. 2023, 405, 133364. [Google Scholar]
  3. Ou, Z.; Feng, R.; Li, F.; Liu, G.; Li, N. Development of drying shrinkage model for alkali-activated slag concrete. Constr. Build. Mater. 2022, 323, 126556. [Google Scholar] [CrossRef]
  4. Wolfs, R.J.M.; Bos, F.P.; Salet, T.A.M. Hardened properties of 3D printed concrete: The influence of process parameters on interlayer adhesion. Cem. Concr. Res. 2019, 119, 132–140. [Google Scholar]
  5. Ding, T.; Xiao, J.; Qin, F.; Duan, Z. Mechanical behavior of 3D printed mortar with recycled sand at early ages. Constr. Build. Mater. 2020, 248, 118654. [Google Scholar]
  6. Mohan, M.K.; Rahul, A.V.; Schutter, G.D.; Tittelboom, K.V. Extrusion-based concrete 3D printing from a material perspec-tive: A state-of-the-art review. Cem. Concr. Compos. 2021, 115, 103855. [Google Scholar]
  7. Zhang, Y.; Zhang, Y.; Liu, G.; Yang, Y.; Wu, M.; Pang, B. Fresh properties of a novel 3D printing concrete ink. Constr. Build. Mater. 2018, 174, 263–271. [Google Scholar]
  8. Hou, S.; Duan, Z.; Xiao, J.; Ye, J. A review of 3D printed concrete: Performance requirements, testing measurements and mix design. Constr. Build. Mater. 2021, 273, 121745. [Google Scholar] [CrossRef]
  9. Jayathilakage, R.; Rajeev, P.; Sanjayan, J. Yield stress criteria to assess the buildability of 3D concrete printing. Constr. Build. Mater. 2020, 240, 117989. [Google Scholar] [CrossRef]
  10. Long, W.-J.; Tao, J.-L.; Lin, C.; Gu, Y.-c.; Mei, L.; Duan, H.-B.; Xing, F. Rheology and buildability of sustainable cement-based composites containing micro-crystalline cellulose for 3D-printing. J. Clean. Prod. 2019, 239, 118054. [Google Scholar]
  11. Chen, M.; Li, L.; Zheng, Y.; Zhao, P.; Lu, L.; Cheng, X. Rheological and mechanical properties of admixtures modified 3D printing sulphoaluminate cementitious materials. Constr. Build. Mater. 2018, 189, 601–611. [Google Scholar]
  12. Liu, C.; Wang, X.; Chen, Y.; Zhang, C.; Ma, L.; Deng, Z.; Chen, C.; Zhang, Y.; Pan, J.; Banthia, N. Influence of hydroxypropyl methylcellulose and silica fume on stability, rheological properties, and printability of 3D printing foam concrete. Cem. Concr. Compos. 2021, 122, 104158. [Google Scholar] [CrossRef]
  13. Zhang, J.; Wang, J.; Dong, S.; Yu, X.; Han, B. A review of the current progress and application of 3D printed concrete. Compos. Part A Appl. Sci. Manuf. 2019, 125, 105533. [Google Scholar] [CrossRef]
  14. Lu, B.; Weng, Y.; Li, M.; Qian, Y.; Leong, K.F.; Tan, M.J. A systematical review of 3D printable cementitious materials. Constr. Build. Mater. 2019, 207, 477–490. [Google Scholar]
  15. Ribeiro, J.; Silva, J.M.; Morais, A.; Cruz, B.F.P.J.S. 3DCP for Complex Sites: Robotic Fabrication of Custom-Fit Slabs in Irregular Pontoons. Archetecture Intell. 2024, 3, 14. [Google Scholar] [CrossRef]
  16. Panda, B.; Tan, M.J. Experimental study on mix proportion and fresh properties of fly ash based geopolymer for 3D concrete printing. Ceram. Int. 2018, 44, 10258–10265. [Google Scholar] [CrossRef]
  17. Van Zijl, G.P.; Paul, S.C.; Tan, M.J. Properties of 3D Printable Concrete. In Proceedings of the 2nd International Conference on Progress in Additive Manufacturing, Singapore, 16–19 May 2016; pp. 421–426. [Google Scholar]
  18. Panda, B.; Paul, S.C.; Tan, M.J. Anisotropic mechanical performance of 3D printed fiber reinforced sustainable construction material. Mater. Lett. 2017, 209, 146–149. [Google Scholar]
  19. Zhang, C.; Nerella, V.N.; Krishna, A.; Wang, S.; Zhang, Y.; Mechtcherine, V.; Banthia, N. Mix design concepts for 3D printable concrete: A review. Cem. Concr. Compos. 2021, 122, 104155. [Google Scholar]
  20. Mohan, M.K.; Rahul, A.V.; Tittelboom, K.V.; Schutter, G.D. Rheological and pumping behaviour of 3D printable cementitious materials with varying aggregate content. Cem. Concr. Res. 2021, 139, 106258. [Google Scholar]
  21. Damtoft, J.S.; Lukasik, J.; Herfort, D.; Sorrentino, D.; Gartner, E.M. Sustainable development and climate change initiatives. Cem. Concr. Res. 2008, 38, 115–127. [Google Scholar]
  22. Xu, Z.; Zhang, D.; Li, H.; Sun, X.; Zhao, K.; Wang, Y. Effect of FA and GGBFS on compressive strength, rheology, and printing properties of cement-based 3D printing material. Constr. Build. Mater. 2022, 339, 127685. [Google Scholar]
  23. Cui, W.; Shen, L.; Ji, D.; Liu, W.; Wang, T.; Hou, D.; Shen, W.; Shi, X.; Tao, Y. Mechanical performance and permeability of low-carbon printable concrete. J. Sustain. Cem.-Based Mater. 2024, 14, 406–416. [Google Scholar] [CrossRef]
  24. Quan, H.V.; Khoa, N.T.; Tho, P.C. Combined effects of ground granulated blast furnace slag and fly ash on the porosity and chloride penetration of sand concrete. In Proceedings of the 2020 Applying New Technology in Green Buildings (ATiGB), Da Nang, Vietnam, 12–13 March 2021. [Google Scholar] [CrossRef]
  25. Fathollah, S.; Razak, H.A. The effect of chemical activators on early strength of ordinary Portland cement-slag mortars. Constr. Build. Mater. 2010, 24, 1944–1951. [Google Scholar]
  26. Li, G.; Zhao, X. Properties of concrete incorporating fly ash and ground granulated blast-furnace slag. Cem. Concr. Compos. 2003, 25, 293–299. [Google Scholar]
  27. Chindaprasirt, P.; Jaturapitakkul, C.; Sinsiri, T. Effect of fly ash fineness on compressive strength and pore size of blended cement paste. Cem. Concr. Compos. 2005, 27, 425–428. [Google Scholar]
  28. Le, T.T.; Austin, S.A.; Lim, S.; Buswell, R.A.; Gibb, A.G.F.; Thorpe, T. Mix design and fresh properties for high-performance printing concrete. Mater. Struct. 2012, 45, 1221–1232. [Google Scholar]
  29. Taqa, A.A.; Mohsen, M.O.; Aburumman, M.O.; Naji, K.; Taha, R.; Senouci, A. Nano-fly ash and clay for 3D-Printing concrete buildings: A fundamental study of rheological, mechanical and microstructural properties. J. Build. Eng. 2024, 92, 109718. [Google Scholar]
  30. Guo, X.; Yang, J.; Xiong, G. Influence of supplementary cementitious materials on rheological properties of 3D printed fly ash based geopolymer. Cem. Concr. Compos. 2020, 114, 103820. [Google Scholar]
  31. Li, D.; Cui, X.; Jang, J.-s.; Wang, G. Sustainable Application of Blast Furnace Slag in the Field of 3D Printing: Material Configuration and Machine Optimization. Sustainability 2024, 16, 4058. [Google Scholar] [CrossRef]
  32. Yu, Q.; Zhu, B.; Li, X.; Meng, L.; Cai, J.; Zhang, Y.; Pan, J. Investigation of the rheological and mechanical properties of 3D printed eco-friendly concrete with steel slag. J. Build. Eng. 2023, 72, 106621. [Google Scholar]
  33. Ma, G.; Yan, Y.; Zhang, M.; Sanjayan, J. Effect of steel slag on 3D concrete printing of geopolymer with quaternary binders. Ceram. Int. 2022, 48, 26233–26247. [Google Scholar]
  34. Samrani, P.; Cao, Y.; Fimbres-Weihs, G.; Sanjaya, E.; Abbas, A. Effect of fly ash and ground waste glass as cement replacement in concrete 3D-Printing for sustainable construction. Front. Built Environ. 2024, 10, 1430174. [Google Scholar] [CrossRef]
  35. ASTM C150-07; Standard Specification for Portland Cement. American Society for Testing and Materials: West Conshehoken, PA, USA, 2012.
  36. CNS 1010, R3032; Method of Test for Compressive Strength of Hydraulic Cement Mortars (Using 50 mm or 2 in. Cube Specimens). Chinese National Standards: Taiwan, China, 1993.
  37. ASTM C 143; Standard Test Method for Slump of Hydraulic-Cement Concrete. American Society for Testing and Materials: West Conshehoken, PA, USA, 2015.
  38. ASTM C94; Standard Specification for Ready-Mixed Concrete. American Society for Testing and Materials: West Conshehoken, PA, USA, 2023.
  39. ASTM D854; Standard Test Methods for Specific Gravity of Soil Solids by the Water Displacement Method. American Society for Testing and Materials: West Conshehoken, PA, USA, 2023.
  40. ASTM C109; Standard Test Method for Compressive Strength of Hydraulic Cement Mortars (Using 2-in. or [50-mm] Cube Specimens). American Society for Testing and Materials: West Conshehoken, PA, USA, 2016.
  41. ASTM C78; Standard Test Method for Flexural Strength of Concrete (Using Simple Beam with Third-Point Loading). American Society for Testing and Materials: West Conshehoken, PA, USA, 2010.
  42. ASTM C642; Standard Test Method for Density, Absorption, and Voids in Hardened Concrete. American Society for Testing and Materials: West Conshehoken, PA, USA, 2013.
  43. ASTM C596; Standard Test Method for Drying Shrinkage of Mortar containing Hydraulic Cement. American Society for Testing and Materials: West Conshehoken, PA, USA, 2009.
  44. Qian, Y.; Schutter, G.D. Enhancing thixotropy of fresh cement pastes with nanoclay in presence of polycarboxylate ether superplasticizer (PCE). Cem. Concr. Res. 2018, 111, 15–22. [Google Scholar]
  45. Rushing, T.S.; Al-Chaar, G.; Eick, B.; Burroughs, J.; Shannon, J.; Barna, L.; Case, M. Investigation of concrete mixtures for additive construction. Rapid Prototyp. J. 2017, 23, 74–80. [Google Scholar]
  46. Hambach, M.; Volkmer, D. Properties of 3D-printed fiber-reinforced Portland cement paste. Cem. Concr. Compos. 2017, 79, 62–70. [Google Scholar]
  47. Tay, Y.W.D.; Panda, B.; Paul, S.C.; Tan, M.J.; Qian, S.Z.; Leong, K.F.; Chua, C.K. Processing and Properties of Construction Materials for 3D Printing. Mater. Sci. Forum 2016, 861, 177–181. [Google Scholar]
  48. Ma, G.; Wang, L.; Ju, Y. State-of-the-art of 3D printing technology of cementitious material-An emerging technique for construction. Sci. China Ser. E Technol. Sci. 2017, 61, 475–495. [Google Scholar]
  49. Sanjayan, J.; Nematollahi, B.; Xia, M.; Marchment, T. Effect of surface moisture on inter-layer strength of 3D printed concrete. Constr. Build. Mater. 2018, 172, 468–475. [Google Scholar]
  50. Paul, S.C.; Tay, Y.W.D.; Panda, B.; Tan, M.J. Fresh and hardened properties of 3D printable cementitious materials for building and construction. Arch. Civ. Mech. Eng. 2018, 18, 311–319. [Google Scholar]
  51. Panda, B.; Paul, S.C.; Hui, L.J.; Tay, Y.W.D.; Tan, M.J. Additive manufacturing of geopolymer for sustainable built environment. J. Clean. Prod. 2017, 167, 281–288. [Google Scholar]
  52. Le, T.T.; Austin, S.A.; Lim, S.; Buswell, R.A.; Law, R.; Gibb, A.G.F. Hardened properties of high-performance printing concrete. Cem. Concr. Res. 2012, 42, 558–566. [Google Scholar] [CrossRef]
  53. Zhang, Y.; Zhang, Y.; She, W.; Yang, L.; Liu, G.; Yang, Y. Rheological and harden properties of the high-thixotropy 3D printing concrete. Constr. Build. Mater. 2019, 201, 278–285. [Google Scholar]
  54. Mehta, P.K.; Monteiro, P.J.M. Concrete: Microstructure, Properties, and Materials, 4th ed.; Prentice-Hall Inc.: New York, NY, USA, 2013. [Google Scholar]
  55. Bissonnette, B.; Pierre, P.; Pigeon, M. Influence of key parameters on drying shrinkage of cementitious materials. Cem. Concr. Res. 1999, 29, 1655–1662. [Google Scholar]
Applsci 15 03933 g001
Figure 1. Fine aggregate grading curve.
Figure 1. Fine aggregate grading curve.
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Figure 2. Picture of the printing process.
Figure 2. Picture of the printing process.
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Figure 3. Schematic diagram of extrudability test determination.
Figure 3. Schematic diagram of extrudability test determination.
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Figure 4. Schematic diagram of buildability evaluation test.
Figure 4. Schematic diagram of buildability evaluation test.
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Figure 5. Schematic diagram of 3D-printed specimens for compressive strength test.
Figure 5. Schematic diagram of 3D-printed specimens for compressive strength test.
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Figure 6. Extrudability of 3DPC.
Figure 6. Extrudability of 3DPC.
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Figure 7. Buildability of 3DPC.
Figure 7. Buildability of 3DPC.
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Figure 8. Unit weight of 3DPC.
Figure 8. Unit weight of 3DPC.
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Figure 9. Compressive strength of 3DPC in X direction.
Figure 9. Compressive strength of 3DPC in X direction.
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Figure 10. Compressive strength of 3DPC in Y direction.
Figure 10. Compressive strength of 3DPC in Y direction.
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Figure 11. Compressive strength of 3DPC in Z direction.
Figure 11. Compressive strength of 3DPC in Z direction.
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Figure 12. Compressive strength of 3DPC in F5S0.
Figure 12. Compressive strength of 3DPC in F5S0.
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Figure 13. Compressive strength of 3DPC in FS25.
Figure 13. Compressive strength of 3DPC in FS25.
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Figure 14. Compressive strength of 3DPC in F0S5.
Figure 14. Compressive strength of 3DPC in F0S5.
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Figure 15. Compressive strength of 3DPC and cast specimens at 28 days.
Figure 15. Compressive strength of 3DPC and cast specimens at 28 days.
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Figure 16. Failure mode in compressive strength test of 3DPC and cast specimens at 28 days.
Figure 16. Failure mode in compressive strength test of 3DPC and cast specimens at 28 days.
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Figure 17. Flexural strength of 3DPC and cast specimens at 28 days.
Figure 17. Flexural strength of 3DPC and cast specimens at 28 days.
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Figure 18. Failure mode in flexural strength test of 3DPC and cast specimens at 28 days.
Figure 18. Failure mode in flexural strength test of 3DPC and cast specimens at 28 days.
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Figure 19. Water absorption of 3DPC.
Figure 19. Water absorption of 3DPC.
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Figure 20. Drying shrinkage of 3DPC.
Figure 20. Drying shrinkage of 3DPC.
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Table 1. Physical properties of PC, GGBFS, and FA.
Table 1. Physical properties of PC, GGBFS, and FA.
Physical PropertiesPCGGBFSFA
Specific gravity3.152.902.08
Specific surface area (m2/kg)364520237
Table 2. Chemical composition of PC, GGBFS, and FA.
Table 2. Chemical composition of PC, GGBFS, and FA.
Chemical Composition (%)PCGGBFSFA
Calcium oxide, CaO 63.5740.532.82
Silicon dioxide, SiO221.0333.5956.48
Aluminum oxide, Al2O35.4714.7020.34
Ferric oxide, Fe2O32.980.486.61
Sulfur trioxide, SO32.010.610.25
Sodium oxide, Na2O0.32---0.33
Potassium oxide, K2O0.700.350.80
Magnesium oxide, MgO2.517.650.93
Loss on ignition, L.O.I.1.381.342.76
Others0.030.758.68
Table 3. The physical properties of anhydrous Na2SiO3 and PCE.
Table 3. The physical properties of anhydrous Na2SiO3 and PCE.
Physical PropertiesAnhydrous Na2SiO3PCE
AppearanceColorless crystalLight yellow
Density (g/mL)2.611.08~1.12
Solid content (%)---43.0~45.0
pH12.55.5~7.5
Table 4. Fine aggregate sieve analysis.
Table 4. Fine aggregate sieve analysis.
Sieve No.Mass Retained (kg)Percentage Retained (%)Cumulative Percentage Retained (%)
#40.0040.40.4
#80.0313.13.5
#160.0818.111.6
#300.19519.531.1
#500.31731.762.8
#1000.25825.888.6
Bottom plate0.11411.4100
F.M.1.98
Table 5. Mix proportions of PC/GGBFS/FA mortars.
Table 5. Mix proportions of PC/GGBFS/FA mortars.
Mix No.Water
(kg/m3)		Cement (kg/m3)GGBFSFA
(kg/m3)		Fine Agg. (kg/m3)Additive (kg/m3)
(kg/m3)Anhydrous Na2SiO3PCE
S5F040050050001500505
SF254005002502501500505
S0F540050005001500505
Table 6. Flowability and slump of OPC/GGBFS/FA mortars.
Table 6. Flowability and slump of OPC/GGBFS/FA mortars.
Mix No.Horizontal
(cm)		Vertical (cm)Average (cm)Flowability (%)Slump
(cm)
S5F021.821.821.81185.9
SF2521.521.321.41145.4
S0F520.620.420.51054.5
Table 7. Buildability of OPC/GGBFS/FA mortars.
Table 7. Buildability of OPC/GGBFS/FA mortars.
Mix No.ΔH (cm)Tilt Angle (Degree)
S5F00.21.51
SF250.11.33
S0F50.31.36
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Tseng, K.-C.; Chi, M.; Yeih, W.; Huang, R. Influence of Slag/Fly Ash as Partial Cement Replacement on Printability and Mechanical Properties of 3D-Printed Concrete. Appl. Sci. 2025, 15, 3933. https://doi.org/10.3390/app15073933

AMA Style

Tseng K-C, Chi M, Yeih W, Huang R. Influence of Slag/Fly Ash as Partial Cement Replacement on Printability and Mechanical Properties of 3D-Printed Concrete. Applied Sciences. 2025; 15(7):3933. https://doi.org/10.3390/app15073933

Chicago/Turabian Style

Tseng, Kuo-Chang, Maochieh Chi, Weichung Yeih, and Ran Huang. 2025. "Influence of Slag/Fly Ash as Partial Cement Replacement on Printability and Mechanical Properties of 3D-Printed Concrete" Applied Sciences 15, no. 7: 3933. https://doi.org/10.3390/app15073933

APA Style

Tseng, K.-C., Chi, M., Yeih, W., & Huang, R. (2025). Influence of Slag/Fly Ash as Partial Cement Replacement on Printability and Mechanical Properties of 3D-Printed Concrete. Applied Sciences, 15(7), 3933. https://doi.org/10.3390/app15073933

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