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Article

Influence of Mixing Conditions on the Strength and Microstructure of Cement Paste

by
Yufan Wan
1,
Hongbo Cao
1,2,*,
Guangqiao Zhang
1,
Xue Lu
2,
Yanru Gao
2,
Jintao Niu
2,
Chuang He
3 and
Xiaolei Lu
2,*
1
Shandong Provincial Key Laboratory of Intelligent Construction and Operation Maintenance of Highway Infrastructure, Shandong Luqiao Group Co., Ltd., Jinan 250014, China
2
Shandong Provincial Key Laboratory of Green and Intelligent Building Materials, University of Jinan, Jinan 250022, China
3
School of Civil Engineering and Architecture, Taizhou University, Taizhou 318001, China
*
Authors to whom correspondence should be addressed.
Buildings 2025, 15(18), 3277; https://doi.org/10.3390/buildings15183277
Submission received: 15 August 2025 / Revised: 31 August 2025 / Accepted: 8 September 2025 / Published: 11 September 2025
(This article belongs to the Special Issue Advanced Cementitious Materials: Integrating Nanotechnology, Sustainability, and Intelligent Design)
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Versions Notes

Abstract

The conventional “one-pot” mixing method employed in concrete production restricts both efficiency and quality optimization. This study systematically investigates the effects of mixing duration and rotational speed on the compressive strength and microstructure of cement paste by varying these parameters. Results indicate that appropriately extending mixing duration and increasing rotational speed enhances the strength of cementitious paste. However, excessive duration or overly high speeds adversely affect strength. When the rotational speed is 250 r/min and the mixing time is 100 s, the compressive strength of the hardened cementitious pastes at all curing ages is good, with strengths of 50.1 MPa, 61.1 MPa, and 77.0 MPa at 3 days, 7 days, and 28 days, respectively. Microstructural analysis further reveals that this mixing condition produced lower porosity, denser morphology, and increased hydration product formation, collectively explaining the superior mechanical properties.

1. Introduction

Concrete, a composite material consisting of cement, aggregates, admixtures, and water, is extensively used in engineering construction [1,2,3]. In conventional mixing, all raw materials are simultaneously introduced into the mixer and blended at a constant speed. This method is operationally simple [4]. However, concrete produced by this method only achieves macroscopic homogeneity. Microscopic analysis reveals that 10~30% of cement particles remain agglomerated into clusters, preventing microscopic uniformity [5]. The Cement Paste Coating Aggregate (CPCA) method first involves uniformly mixing cement particles with water to form cement paste, followed by the incorporation of aggregates for homogeneous blending. This approach enhances cement hydration and strengthens the interfacial transition zone (ITZ), improving concrete strength and overall performance. Furthermore, it reduces mixing duration and enhances cost efficiency [6,7,8]. Therefore, optimizing cement paste performance is critical for improving concrete performance.
Mix proportion adjustment is the most widely employed method for enhancing the mechanical properties of cement-based materials. Increasing cementitious material content enhances concrete compactness [9,10], consequently improving compressive strength. Properly increasing the water-binder ratio can improve the fluidity of the cement paste and improve the hydration of cement, but excessive ratios will induce excessive porosity, resulting in a decrease in strength [11]. Moreover, suitable admixtures effectively optimize mechanical properties. Ji [12] found that magnesium slag as a mineral admixture is beneficial to improve the workability of concrete, while its pozzolanic effect enhances hydration product formation and long-term strength. Wang et al. [13] reported that granulated blast furnace slag (GBFS) can effectively counteract steel slag’s detrimental effects on concrete strength. This improvement stems from GBFS micro-powder reducing macropores while increasing micropores, thus refining the pore structure. Recently, nanomaterials have gained widespread application for improving cement-based materials’ physical properties and durability [14,15,16]. These nanomaterials enhance cement paste compactness via filling and nucleation effects, consequently improving mechanical performance and durability [17,18]. He [19] synthesized recycled nano-FeB from construction waste iron powder. At 0.075% nano-FeB content, the 28-day compressive strength of the composite cement paste reached 53.7 MPa, representing a 39.8% increase compared to the control group. Long [20] revealed that carbon dots (CDs) accelerate C-S-H gel formation through nucleation effects. Remarkably, 0.1 wt% CD incorporation elevated mortar compressive strength by 17%.
The cement paste mixing process critically governs material properties, influencing both homogeneity and hydration kinetics. Research demonstrates that extended mixing durations enhances uniaxial compressive strength, with a more pronounced effect on early-age strength than long-term strength [21]. However, prolonged mixing introduces excessive air entrainment, reducing both thermal conductivity and paste strength [22]. Evidently, both excessive and insufficient mixing durations detrimentally affect cement paste properties. Reported optimal mixing times vary significantly across experimental conditions Zheng [23] established a reference mixing duration of 60~90 s for standard test ratios. Ren [24] identified 90~120 s as the optimal range for maximizing concrete performance. Yan et al. [25] demonstrated that 50 s of vibration mixing optimized both early and long-term compressive strengths. Gao [26] revealed that twin-shaft horizontal mixers reduce optimal mixing time by 40% versus single-shaft counters. Furthermore, mixing speed substantially modifies paste viscosity, directly influencing performance characteristics. Lu et al. [27] reported that with triethanolamine (TEA), increasing mixing speed initially prolonged and subsequently shortened the induction period, resulting in a corresponding nonlinear change in setting time (first reduced, then extended). Han [28] found that rheological properties improve with mixing intensity within proper ranges. Juilland et al. [29] demonstrated that elevated shear forces during mixing accelerate early hydration, densifying cement matrices. Nonetheless, excessive mixing speeds introduce excessive air entrainment, increasing the porosity of the concrete microstructure and ultimately reducing compressive strength [30]. The aforementioned studies confirm that mixing parameters significantly affect the mechanical properties of cement paste. However, current research emphasizes material proportion optimization over preparation process engineering for performance enhancement. Although it is well-established that mixing parameters can significantly affect the performance of cement paste, the comprehensive influence of stirring time and speed, particularly on its microstructure, still requires further investigation.
Accordingly, this study systematically examines the effects of mixing duration and rotational speed on the mechanical properties of cement paste through controlled variations in these parameters. Furthermore, X-ray diffraction (XRD), scanning electron microscopy (SEM), and low-field nuclear magnetic resonance (LF-NMR) were employed to elucidate their impacts on hydration products and porosity evolution, aiming to establish technical pathways and provide empirical support for optimizing cement paste performance.

2. Materials and Methods

2.1. Materials

This research used 42.5 ordinary Portland cement (China Shanshui Cement Group Limited, Jinan, China), Grade II fly ash, and S95-grade ground granulated blast furnace slag (GGBS) (Shandong Luqiao Group Co., Ltd., Jinan, China) as the cementitious materials. The chemical composition is shown in Table 1, and the physical and mechanical properties of the cement are shown in Table 2. Polycarboxylate superplasticizer was used as admixture, and its solid content was 25%.

2.2. Preparation of Cementitious Paste

This study employed a C50-grade concrete mix design, modified by excluding aggregates to create cementitious paste specimens. At the same time, three mixing times (50 s, 75 s, and 100 s) and three rotational speeds (200 r/min, 250 r/min, and 300 r/min) were designed. A total of 9 different stirring conditions were designed to prepare 40 mm × 40 mm × 40 mm cube specimens. The mix ratio is shown in Table 3.

2.3. Compressive Strength Test

The constituent materials were weighed according to the proportions specified in Table 3 and transferred to a mixing barrel. The mixture was subsequently mixed under the nine aforementioned stirring conditions, cast into molds, and vibrated for 60 times. Following standard curing for 1 day, the specimens were demolded and curing was continued until the specified test ages. The compressive strength was measured at 3, 7, and 28 days in accordance with the standard GB/T 17671-2021 (“Methods for testing the strength of cement mortar (ISO method)”) [31].

2.4. Microstructure Characterization

Core samples were selected from the crushed specimens after compressive testing and ground into blocks smaller than 1 cm3. Hydration was terminated using isopropanol, followed by drying in a vacuum oven at a constant temperature of 40 °C for 48 h. The samples were then sealed and stored.
  • XRD
The phase composition of all samples was tested using a D8 ADVANCE (Bruker, Karlsruhe, Germany) X-ray diffractometer (XRD). The hydration-stopped samples were ground into powders with a particle size of less than 75 μm. The testing conditions were as follows: copper target (Cu-Kα radiation, λ = 0.154 nm), working voltage of 20 kV, working current of 5 mA, scanning speed of 10°/min, and scanning range of 5°~70°.
2.
SEM
The microstructure of the samples was observed by a ZEISS (Carl Zeiss AG, Oberkochen, Germany) Gemini 360 field emission electron microscope. Before the test, samples with regular shapes and relatively flat surfaces were selected and subjected to gold sputtering coating. The operating parameters were set as follows: accelerating voltage of 0.2~30 kV, magnification of 150,000~200,000, and secondary electron image resolution of 1.0 nm.
3.
LF-NMR
Before testing, the samples must undergo 24 h vacuum water saturation treatment in an NM-V vacuum pressure saturation device to ensure water fills the pores within the samples. Subsequently, the pore structure of the samples was characterized using a MicroMR20-025V low-field nuclear magnetic resonance (NMR) analyzer (manufactured by Suzhou Niumag Corporation, Suzhou, China). The testing parameters included a constant magnetic field of 0.3 T, an electromagnetic coil diameter of 25 mm, and an operating frequency of 20 MHz.

3. Results and Discussion

3.1. Compressive Strength

The results showed that the compressive strength of cement paste increased with increasing stirring time at a fixed speed; however, the sample stirred at 300 r/min for 100 s exhibited an anomalous result. Specifically, Figure 1a shows the effect of mixing time on the compressive strength of cementitious paste at 200 r/min. It can be seen from the figure that the compressive strength of cementitious paste increases with the increase in mixing time at different ages, indicating that at this rotational speed, the extension of mixing time can improve the compressive strength of cementitious paste. This phenomenon may be attributed to the fact that a longer mixing time facilitates better dispersion of cement particles, improves the degree of cement hydration, and consequently enhances the mechanical properties of the cementitious paste. Figure 1b demonstrates that prolonging the mixing time at 250 r/min also enhances the compressive strength of cementitious paste. When the mixing time increased from 50 s to 75 s, the 3 d, 7 d, and 28 d compressive strengths improved by 37.80%, 35.75%, and 25.6%, respectively. However, when the mixing time further extended from 75 s to 100 s, the strength gains decreased to 10.84%, 9.68%, and 13.74% for the corresponding curing ages. This may be because when the mixing time is 75 s, the cementitious paste has good dispersibility, and the increase in compressive strength decreases with the increase in mixing time [32]. As shown in Figure 1c, when the rotational speed is 300 r/min, the compressive strength of the cementitious paste initially increases but then decreases with prolonged mixing time. The maximum compressive strength is achieved at a mixing time of 75 s, with 3 d, 7 d, and 28 d strengths reaching 43.3 MPa, 50.6 MPa, and 65.3 MPa, respectively. However, when the mixing time is extended to 100 s, the compressive strength decreases to 38.8 MPa, 40.6 MPa, and 41 MPa for the corresponding curing ages. This reduction in strength may be attributed to segregation of the cementitious paste caused by excessive mixing time, which negatively affects its mechanical properties [33].
As shown in Figure 2, under the same mixing time, the compressive strength of cement paste increased with increasing rotational speed; but the sample mixed at 300 r/min for 100 s displayed an anomaly. Figure 2a illustrates the effect of rotational speed on compressive strength at a constant mixing time of 50 s. It can be seen from the figure that the compressive strength of cementitious paste increases with the increase in rotational speed, which shows that the increase in rotational speed is beneficial to the improvement of compressive strength of cementitious paste. This is attributed to the dispersion of cementitious paste. Higher mixing energy effectively breaks up agglomerated cement particles, promotes their uniform distribution, and accelerates cement hydration—all of which contribute to improved mechanical properties. Figure 2b,c demonstrates that when the mixing time is 75 s and 100 s, the compressive strength of cementitious paste first increases and then decreases with the increase in rotational speed. When the rotational speed exceeds 250 r/min, further increasing the rotation rate will deteriorate the strength of the cementitious paste. The possible reason is that excessive rotational speed significantly intensifies the movement of the paste, causing air to be entrapped in the mixture, which increases porosity and consequently has a negative impact on strength. It is noteworthy that when the mixing time is 100 s, the degradation behavior of high speed on compressive strength is more obvious. The compressive strength of 3 d, 7 d, and 28 d at 300 r/min decreased by 11.3 MPa, 20.5 MPa, and 36.0 MPa compared with 250 r/min, and decreased by 7.1 MPa, 6.1 MPa, and 29.3 MPa compared with 200 r/min. This indicates that prolonged mixing time combined with excessively high rotational speeds leads to inhomogeneity in the cementitious paste, thereby reducing its strength [34].
Increasing mixing time or rotational speed can improve strength development; however, excessive duration or speed adversely affects strength performance. Therefore, in field applications, appropriate mixing time and speed should be selected based on engineering requirements. In this study, the maximum compressive strength was achieved at a mixing time of 100 s and a speed of 250 r/min, with corresponding 3 d, 7 d, and 28 d strengths of 50.1 MPa, 61.1 MPa, and 77.0 MPa, respectively.

3.2. Phase Composition

Samples under different rotational speeds (200 r/min, 250 r/min, 300 r/min) with mixing durations of 50 s and 100 s were selected for XRD analysis. Figure 3 shows the XRD patterns of different mixing conditions at 3 days. As illustrated, the main phase in all samples is Ca(OH)2. Additionally, the primary peak of ettringite is observed at 9.1°, and the main peak of Hc is detected at 10.8°. This indicates that the cementitious paste had achieved a relatively high degree of hydration by 3 days. Comparing samples with mixing durations of 50 s and 100 s reveals that prolonging the mixing time did not alter the composition of the hydration products at 3 days. Among them, at 250 r/min, compared to the sample mixed for 50 s, the unhydrated peak at around 29.4° in the sample mixed for 100 s significantly decreased. This indicates that prolonging the mixing time promotes the hydration of the cementitious paste and enhances early strength, which is also consistent with the higher strength of the hardened cementitious paste under the 250 r/min, 100 s mixing condition mentioned earlier. Figure 4 shows the XRD patterns of different mixing conditions at 7 days. As can be seen from Figure 4, with the extension of curing age, the peak value of ettringite decreases. This is because with the progress of hydration, the gypsum in cement is gradually consumed, and ettringite is gradually decomposed into AFm, which readily reacts with CO2 in the air to form Hc [35]. Additionally, calcium carbonate was also observed in the XRD pattern, which was attributed to the carbonation of the hydration product Ca(OH)2. When the mixing time is 50 s and the rotational speed is 200 r/min, the strength of the hydration product peak is the lowest, indicating that insufficient mixing time and lower rotational speed reduced the homogeneity of the cementitious paste, thereby hindering hydration and resulting in the lowest compressive strength.
The XRD patterns of different mixing conditions at 28 days are shown in Figure 5. When the mixing time was 50 s, the diffraction peak intensities of Ca(OH)2 and Hc increased with the increase in rotational speed, indicating that under this mixing duration, higher rotational speed could promote cement hydration and generate more hydration products, while having minimal impact on the phase composition of the hydration products. When the mixing time was 100 s, the diffraction peak intensity of Ca(OH)2 initially increased and then decreased with the rise in rotational speed, reaching its maximum at 250 r/min, after which the peak intensity declined with further speed increases. This suggests that under longer mixing durations, a moderate increase in rotational speed can enhance hydration, with more hydration products filling the cementitious paste, macroscopically manifesting as higher compressive strength. However, as the rotational speed continues to increase, excessively high speeds may adversely affect cement hydration, thereby impairing strength development.

3.3. Microstructure

To better observe the microstructure of the samples, some specimens from the 7-day curing period were selected for observation under a scanning electron microscope (SEM) to investigate the effect of mixing time on the hydration products of cementitious paste. Figure 6a–d show SEM images of the cementitious paste at 7 days under the mixing condition of 100 s and 250 r/min. As seen in Figure 6a,b, the cementitious paste contains an abundance of flaky Hc phases and plate-like Ca(OH)2, which is consistent with the XRD analysis. Figure 6c reveals the presence of a substantial amount of C-S-H gel in the hardened cementitious paste, which is bonded together with other hydration products such as ettringite, adhering to the surface of cement particles. This indicates that a large quantity of hydration products had already formed by 7 days. As shown in Figure 6d, the cementitious paste exhibits a dense structure at this curing age, suggesting a high degree of hydration. Figure 7a,b presents SEM images of the cementitious paste at 7 days under the mixing condition of 50 s and 250 r/min. It can be observed that under this mixing condition, the cementitious paste also generated a significant amount of C-S-H gel and plate-like Ca(OH)2. Compared to the cementitious paste mixed under the condition of 100 s 250 r/min, the sample mixed at 250 r/min for 50 s exhibited a more porous structure with a higher content of unhydrated fly ash particles. This phenomenon may be attributed to the shorter mixing duration under this condition, which could hinder sufficient particle dispersion and consequently reduce cement hydration, ultimately leading to lower sample strength [36]. These observations are consistent with the previous findings that the hardened cementitious paste prepared under 100 s 250 r/min mixing condition demonstrated higher compressive strength.

3.4. Pore Structure

In cementitious structures, porosity and pore size distribution are critical factors influencing their strength. There is a negative correlation between porosity and strength: as porosity increases, internal defects increase, reducing the effective load-bearing area of the material and consequently leading to a decline in strength [37,38]. Based on the findings from previous research, samples prepared under the following mixing conditions—50 s 250 r/min, 100 s 200 r/min, 100 s 250 r/min, and 100 s 300 r/min—were selected for pore structure characterization.
Figure 8 shows the cumulative pore volume change in C50 cementitious paste. As can be seen from the figure, the cementitious paste mixed at 100 s 250 r/min exhibits the lowest cumulative porosity, which aligns with its previously reported highest compressive strength. In contrast, the sample mixed at 100 s 300 r/min has the highest cumulative porosity, while those mixed at 100 s 200 r/min and 50 s 250 r/min show similar porosity levels. Among all groups, the steepest slope of the curve occurs in the 0.001~0.01 μm pore size range, indicating that the majority of pores in the cementitious paste fall within this nanometer-scale range.
Figure 9 presents the relationship between relaxation time (T2) and signal intensity for C50 concrete cementitious paste under different mixing conditions. As shown in the figure, the main peak of the T2 spectrum for all mixing conditions falls within the 0.1–1 ms range, corresponding to pores smaller than 10 nm. This indicates most of the pore sizes in the cement slurry under different stirring conditions are less than 10 nm, which is consistent with the cumulative porosity results. When the mixing time is fixed at 100 s, the peak intensity of the T2 spectrum first decreases and then increases with higher rotational speeds, reaching its lowest point at 250 r/min. This indicates that under prolonged mixing durations, moderately increasing the rotational speed helps enhance the compactness of the cementitious paste, whereas excessively high speeds lead to increased porosity. The reason is that overly rapid mixing introduces excessive air bubbles, thereby raising the porosity of the concrete structure. When the rotational speed is 250 r/min, extending the mixing time effectively reduces the porosity of the cementitious paste. According to XRD, this is because prolonged mixing at this speed promotes cement hydration, generating abundant hydration products that fill internal pores, thereby improving the density of the hardened cementitious paste.
Figure 10 shows the pore size distribution of C50 cementitious paste. As can be seen from the figure, the pores in the cementitious paste under different mixing conditions are predominantly harmless, accounting for more than 75% of the total porosity, with pore sizes smaller than 20 nm [39]. When the mixing time is 100 s, an increase in rotational speed from 200 r/min to 250 r/min leads to a decrease in the proportion of harmless pores and an increase in the proportion of harmful pores. However, when the rotational speed continues to rise to 300 r/min, the proportion of harmful pores decreases. This phenomenon may be attributed to the high-speed stirring, which introduces more air bubbles into the cementitious paste, leading to an increase in larger bubbles that subsequently form harmful pores after hardening. However, as the rotational speed further increases, these larger bubbles are broken down into smaller ones, resulting in a reduction in the proportion of harmful pores. When the rotational speed is 250 r/min, prolonged mixing time causes a decrease in the proportion of harmless.
The experimental results indicate that the cementitious paste mixed at 250 r/min for 100 s exhibits the lowest porosity, corresponding to superior compressive strength. Both excessively high and low rotational speeds lead to increased porosity, while a relatively higher rotational speed can improve pore size distribution. Furthermore, appropriately extending the mixing duration helps reduce porosity.

4. Conclusions

The influence of mixing parameters on the strength, pore structure, and hydration products of hardened cementitious paste was investigated by controlling the mixing time and mixing rate of the cementitious paste. The main conclusions are as follows:
(1)
At rotational speeds of 200 and 250 r/min, extended mixing duration enhances compressive strength, whereas at 300 r/min, excessive mixing duration adversely affects strength development. When mixing durations below 75 s, compressive strength shows a positive correlation with rotational speed, while beyond this threshold, higher speeds result in strength reduction. The optimal compressive strength was observed at 100 s mixing duration and 250 r/min, with 3 d, 7 d, and 28 d strengths reaching 50.1 MPa, 61.1 MPa, and 77.0 MPa, respectively.
(2)
Variations in rotational speed and time exerted a minor influence on the phase composition and morphology of hydration products in the cementitious paste. An extended mixing duration facilitated cement hydration and improved the compactness of the hardened cementitious paste. Moderately increasing the rotational speed enhanced the content of hydration products, but excessive speeds adversely affected cement hydration.
(3)
Both excessively high and low rotational speeds lead to an increase in the total porosity of hardened cementitious paste. The lowest porosity was achieved when mixing at 250 r/min for 100 s, correlating with the optimal compressive strength performance. Under these conditions, over 75% of the pores in the sample were classified as harmless, with diameters below 20 nm.
The effect of mixing process on the long-term performance of cement paste is not clear, and further exploration is still needed. In addition, in future research, the influence of mixing process on the microstructure of cement paste can be further explored in combination with machine learning [40]. For example, the cement hydration products (C-S-H gel, Ca(OH)2), unhydrated cement particles, aggregates, and pores in the SEM image are segmented by DeepLab [41], and the volume fraction of each component is calculated.

Author Contributions

Conceptualization, H.C. and X.L. (Xiaolei Lu); formal analysis, X.L. (Xue Lu) and C.H.; Investigation, Y.W. and G.Z.; Data curation, Y.G. and J.N.; Visualization, Y.W. and X.L. (Xue Lu); Writing—original draft, G.Z. and Y.G.; Writing-review and editing, H.C. and X.L. (Xiaolei Lu); Project administration, C.H. and J.N. All authors have read and agreed to the published version of the manuscript.

Funding

This work was supported by the National Natural Science Foundation of China (52102020, 52472028), Shandong Natural Science Foundation Project (ZR2024ME033), and the 111 Project of International Corporation on Advanced Cement-based Materials (No. D17001).

Data Availability Statement

The data presented in this study are available upon request from the author.

Conflicts of Interest

Authors Yufan Wan, Hongbo Cao and Guangqiao Zhang were employed by the company Shandong Provincial Key Laboratory of Intelligent Construction and Operation Maintenance of Highway Infrastructure, Shandong Luqiao Group Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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Figure 1. Fixed rotational speed (a) 200 r/min; (b) 250 r/min; (c) compressive strength under different mixing times (300 r/min).
Figure 1. Fixed rotational speed (a) 200 r/min; (b) 250 r/min; (c) compressive strength under different mixing times (300 r/min).
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Figure 2. Fixed mixing time ((a) 50 s; (b) 75 s; (c) 100 s). Compressive strength at different rotational speeds.
Figure 2. Fixed mixing time ((a) 50 s; (b) 75 s; (c) 100 s). Compressive strength at different rotational speeds.
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Figure 3. 3 d XRD pattern of C50 cementitious paste.
Figure 3. 3 d XRD pattern of C50 cementitious paste.
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Figure 4. 7 d XRD pattern of C50 cementitious paste.
Figure 4. 7 d XRD pattern of C50 cementitious paste.
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Figure 5. 28 d XRD pattern of C50 cementitious paste.
Figure 5. 28 d XRD pattern of C50 cementitious paste.
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Figure 6. SEM images of C50 cementitious paste at various magnifications under a mixing condition of 100 s at 250 r/min ((a) 20 kX; (b) 25 kX; (c) 13 kX; (d) 4 kX).
Figure 6. SEM images of C50 cementitious paste at various magnifications under a mixing condition of 100 s at 250 r/min ((a) 20 kX; (b) 25 kX; (c) 13 kX; (d) 4 kX).
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Figure 7. SEM images of C50 cementitious paste at various magnifications under a mixing condition of 50 s at 250 r/min ((a) 10 kX; (b) 2kX).
Figure 7. SEM images of C50 cementitious paste at various magnifications under a mixing condition of 50 s at 250 r/min ((a) 10 kX; (b) 2kX).
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Figure 8. The cumulative pore volume change in C50 cementitious paste.
Figure 8. The cumulative pore volume change in C50 cementitious paste.
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Figure 9. Signal intensity change in C50 cementitious paste.
Figure 9. Signal intensity change in C50 cementitious paste.
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Figure 10. Pore size distribution of C50 cementitious paste.
Figure 10. Pore size distribution of C50 cementitious paste.
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Table 1. Chemical composition of cementitious materials (%).
Table 1. Chemical composition of cementitious materials (%).
MaterialsCaOSiO2Al2O3Fe2O3SO3MgOOthers
Cement59.421.67.23.52.92.52.9
Fly ash3.038.930.53.21.20.422.8
GGBS36.030.913.60.32.28.38.7
Table 2. Physical and mechanical properties of cement.
Table 2. Physical and mechanical properties of cement.
Standard Consistency Water Consumption
(%)		Initial Setting Time
(min)		Final Setting Time
(min)		Compressive Strength
(MPa)		Flexural Strength
(MPa)
291703307 d28 d7 d28 d
30.749.45.37.9
Table 3. Mix proportion of cementitious paste (%).
Table 3. Mix proportion of cementitious paste (%).
MaturityCementFly AshGGBSWaterSuperplasticizer
C50651520270.9
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Wan, Y.; Cao, H.; Zhang, G.; Lu, X.; Gao, Y.; Niu, J.; He, C.; Lu, X. Influence of Mixing Conditions on the Strength and Microstructure of Cement Paste. Buildings 2025, 15, 3277. https://doi.org/10.3390/buildings15183277

AMA Style

Wan Y, Cao H, Zhang G, Lu X, Gao Y, Niu J, He C, Lu X. Influence of Mixing Conditions on the Strength and Microstructure of Cement Paste. Buildings. 2025; 15(18):3277. https://doi.org/10.3390/buildings15183277

Chicago/Turabian Style

Wan, Yufan, Hongbo Cao, Guangqiao Zhang, Xue Lu, Yanru Gao, Jintao Niu, Chuang He, and Xiaolei Lu. 2025. "Influence of Mixing Conditions on the Strength and Microstructure of Cement Paste" Buildings 15, no. 18: 3277. https://doi.org/10.3390/buildings15183277

APA Style

Wan, Y., Cao, H., Zhang, G., Lu, X., Gao, Y., Niu, J., He, C., & Lu, X. (2025). Influence of Mixing Conditions on the Strength and Microstructure of Cement Paste. Buildings, 15(18), 3277. https://doi.org/10.3390/buildings15183277

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