Sage Journals: Discover world-class research

Abstract

Nanomaterial, as a new emerging material in the field of civil engineering, has been widely utilized to enhance the mechanical properties of cementitious material. Nano-SnO₂ has presented high hardness characteristics, but there is little study of the application of nano-SnO₂ in the cementitious materials. This study mainly investigated the hydration characteristics and strength development of Portland cement paste incorporating nano-SnO₂ powders with 0%, 0.08%, and 0.20% dosage. It was found that the early-age compressive strength of cement paste could be greatly improved when nano-SnO₂ was incorporated with 0.08% dosage. The hydration process and microstructure were then measured by hydraulic test machine, calorimeter, nanoindentation, X-ray diffraction, scanning electron microscope, and mercury intrusion porosimetry. It was found that the cement hydration process was promoted by the addition of nano-SnO₂, and the total amount of heat released from cement hydration is also increased. In addition, the addition of nano-SnO₂ can promote the generations of high density C-S-H and reduce the generations of low density C-S-H indicating the nucleation effect of nano-SnO₂ in the crystal growth process. The porosity and probable pore diameter of cement paste with 0.08% nano-SnO₂ were decreased, and the scanning electron microscopic results also show that the cement paste with 0.08% nano-SnO₂ promotes the densification of cement microstructure, which are consistent with the strength performance.

Keywords

cement mechanical properties hydration nanoindentation

Introduction

Cement-based material, as one of the common and widely used building materials in the world, is a nanostructured, multi-phase, composite material with going-on hydration.¹ Research has shown that more than 70% hydration products of cement-based material is C-S-H (xCaO·SiO₂·yH₂O) gel with nanostructure, which plays an important role on the strength of the hardened paste.² In the hardened cement paste, the main contribution to strength is the nanometer size (10⁻⁹ m) effect of nanoscale chemical bonding which exists among C-S-H gel.³ Recently, nanotechnology has attracted considerable scientific interest due to the new potential uses of particles in nanometer scale. The addition of nanoparticles can dramatically improve properties such as compressive strength and microstructure comparing with conventional grain-size materials of the same chemical composition.⁴ The application of nanomaterials in cement-based materials is a new and promising research field. Since then, several application researches of nanomaterials in cement-based materials have been investigated. It was found that the water absorption of cement mortar could be reduced by 93.47% with SiO₂ at polymethylhydrosiloxane (PMHS) as a surface treatment compared with the control sample.⁵ The effect of silica fume as a dispersion of SiO₂ on the hydration and hardness properties of cement was also studied.⁶ It was found that the addition of silica fume improved the early and late compressive strength and promoted the hydration degree of cement. Barbhuiya et al.⁷ found that Al₂O₃ had no effect on the strength at the early age, whereas Al₂O₃ promoted the increase of calcium hydroxide crystals and the densification of cement microstructure. The addition of TiO₂ was found to promote cement hydration, reduce porosity, enhance compressive strength, and reduce shrinkage.⁸ There is also research investigating that the early compressive strength was able to be significantly improved by the MXene.⁹ The previous research results revealed that the hydration properties have been changed more or less after the addition of nanomaterials.

Nano-SnO₂, as a kind of material with high hardness, strong corrosion resistance, and good chemical and thermal stability, has attracted the attention of many research laboratories in the field of gas sensors (mainly alcohol) and electronic component.^10,11 Tsuruta et al.¹² found that the gas-sensitive device made of SnO₂ worked at 500°C for a week and kept its structure intact while its 500°C thermal cycle could be completed within 10 s. And nanoneedle-assembled SnO₂ has more quicker gas response and recovery.¹³ The Mohs hardness of nano-SnO₂ is 7–8, which has potentiality to promote and increase the strength development when it was added in the cement-based materials. But there is little study on the application of nano-SnO₂ in cement-based materials. In view of these advances, the aim of this study is to investigate the effects of nano-SnO₂ on the characteristics of cement paste. Then, the effects of nano-SnO₂ on the compressive strength, nanoindentation, hydration heat, hydration products, morphology of hydration products, and pore structure were also measured. It is anticipated that the results would provide guidance on the application of nano-SnO₂ on the cementitious material.

Materials and experiments

Materials

The component analysis of P.I 42.5 Portland cement (Qufu United Cement Company, China) used in this study is shown in Table 1. The preparation process of nano-SnO₂ is with reference to Mazloom et al.,¹⁴ and the transmission electron microscopy graph of nano-SnO₂ particles is shown in Figure 1. Figure 2 is the result of nano-SnO₂ particle size distribution. It is apparent that the particle size of nano-SnO₂ is in the range of 50 to 70 nm. Most of the nano-SnO₂ particles are found to be well dispersed, but some agglomeration still occurs. Mixing water was distilled water.

Table 1.

Chemical composition of P.I 42.5 Portland cement.

SiO₂	Al₂O₃	Fe₂O₃	CaO	MgO	SO₃	Na₂O_eq	f-CaO	Loss
21.18%	4.73%	3.41%	62.49%	2.53%	2.83%	0.56%	0.72%	1.76%

Figure 1.

TEM image of nano-SnO₂.

Figure 2.

Nano-SnO₂ particle size distribution.

Mix proportion and experimental methods

Mix proportion

In this experiment, the nano-SnO₂ was added at 0.00%, 0.08%, and 0.20% dosage by weight of cement. Nano-SnO₂ and distilled water were weighed according to the mix proportion and put it into a clean beaker. Then the beaker was put in an ultrasonic cleaning instrument, for dispersing for 5 min to prepare dispersion liquid. The dispersion of nano-SnO₂ in different dosage (0.00%, 0.08%, and 0.20%) and different environments (with and without Ca(OH)₂) is shown in Figure 3. As can be seen from Figure 3, the dispersion of nano-SnO₂ with different dosage in different dispersing environments has little difference at 30 min. The water–cement ratio is 0.35.^15–17 The cement was then added into the dispersion liquid, and the mixture was stirred at low speed for 2 min and then at high speed for 2 min in the cement paste mixer after pausing for 15 s. The cement paste was immediately poured into a 20 mm × 20 mm × 20 mm mold for the compressive strength tests and cured in saturated lime water at room temperature. After 24 h, the specimens were removed from the mold and cured at 20°C ± 1°C and 95% relative humidity until testing compressive strength. After compressive strength test, the samples for the microscopic tests are packed in small bottle with anhydrous ethanol to prevent the cement hydration reaction. Microstructural properties of hydrated cubes were evaluated at the age of 1, 3, and 7 days.

Figure 3.

Dispersion of different dosage of nano-SnO₂ in water and Ca(OH)₂ solution.

Rheological measurements

The rheological parameters of cement paste were characterized by Modular Compact Rheometer (MCR302, Anton Paar Co, Austria). Before testing, the cement paste was prepared according to Chinese Standard GB/T8077-2000. And two rheological parameters of yield stress and plastic stress were used to characterize the rheological properties of cement paste.

Compressive strength

The compressive strength of the cement paste was measured based on GB/T17671-1999 (The National Standard of the People’s Republic of China) by using a WDW-20 hydraulic test machine (Jinan Ruijin Experimental Instrument Co., China). All of the specimens were cast in 20 mm × 20 mm × 20 mm cubic samples, and the average compressive strength of cement paste was assessed by using three cubic samples. The loading rate of the test was controlled by 0.5 mm/min.

Hydration analysis

The hydration exothermic rate of each paste was measured by TAM Air calorimeter (TA Instruments Co., USA) to assess the effect of nano-SnO₂ on the hydration of cement paste. Samples were prepared with a water–binder (w/b) ratio of 0.5, with mixtures (cement was evenly mixed with nano-SnO₂ of 0.00%, 0.08%, and 0.20% dosage in advance) and mixing water at a temperature of 20°C. Binding material-cement and nano-SnO₂, total of 4 g was added in the 20 mL disposable glass ampule, and water (2 g) was loaded in the syringe(s), the admix ampule is first equilibrated in the TAM Air calorimeter with the materials separated for 30 min. Pushing the syringe(s) with stirring the cement paste, the reaction can then be initiated by manually injecting the water from the syringe(s) into the glass ampule. Then, the hydration exothermic rate within 72 h was tested.

Nanoindentation measurement

To determine the effect of nano-SnO₂ on the nanoscale mechanical properties of cement paste, a statistical nanoindentation technique was applied. Young’s modulus of cement pastes was measured by the Hysitron TI Premier Nanoindenter (BRUKER Co. Germany). The operating conditions of the instrument were operated as follows: the load force resolution was less than 1 nN, the displacement resolution was less than 0.01 nm, and the standard Berkovich diamond indenter was used. The distance between the indentation lattices is 10 µm to ensure the independence of the adjacent indentation points the elastic modulus and hardness of samples could be obtained by using the test lattice of 8 × 8 and using 5-2-5(s) loading mode at the same time.

X-ray diffraction analysis

X-ray diffraction (XRD) was used to analyze the hydration products phase of cement pastes. The samples dried at 70°C for 2 h were crushed and grounded to powder. XRD (D8 ADVANCE, Bruker, Germany) tests were conducted with a powder diffraction method, with Cu Ka, voltage 40 kV, and current 40 mA. Scan range was set from 5° to 80° with the speed of 0.02°/step and 0.4 s/step.

Scanning electron microscope test

Scanning electron microscope (SEM, JSM-6390LVH, Jeol, Japan) was used to analyze the morphology of cement paste. Small fractured samples at every hydration age were soaked in anhydrous ethanol to stop hydration and dried at 60°C for 4 h. Then, the sample was coated with 20 nm of gold to make it conductive.

Mercury intrusion porosimetry test

Mercury intrusion porosimetry (MIP, GT-60, American Quantachrome Instruments Company, Florida, USA) was used to test the pore structure of cement paste modified by nano-SnO₂. Small fractured samples at 28 days were soaked in anhydrous ethanol to stop hydration and then dried at 80°C for 2 h.

Results and discussion

Rheological property

The curves of shear stress to shear rate of cement paste with different contents of nano-SnO₂ are shown in Figure 4. From Figure 4, it can be seen that with the addition of 0.08% nano-SnO₂, the shear stress of the cement paste presents insignificant change compared to the reference sample without nano-SnO₂. With the dosage of nano-SnO₂ increased to 0.20%, the shear stress of the cement paste was increased about 8% compared to the reference sample, indicating that the cement paste becomes a little viscous with the increase of nano-SnO₂ content.

Figure 4.

Effect of nano-SnO₂ content on the shear stress of cement paste.

Compressive strength

The modification effect of nano-SnO₂ on cement can be expressed through its influence on the macroscopic mechanical properties. The effects of nano-SnO₂ with different dosage of 0.00%, 0.08%, and 0.20% by the weight of cement on the compressive strength of cement paste are shown in Figure 5. It is revealed that the rate of compressive strength gains of paste with adding nano-SnO₂ is enhanced at early ages. However, the higher the nano-SnO₂ dosage, the lower the enhancement, especially at 3 days of 0.20% dosage; the compressive strength decreased a little compared with the sample with 0.08% dosage nano-SnO₂. The compressive strength of cement pastes with 0.08% nano-SnO₂ dosage was increased by 41.1%, 4.4%, and 10.6% at 1, 3, and 7 days, respectively. To explore the reasons for the strength gain characteristics of the cement paste, the early-age hydration characteristics of Portland cement paste were further evaluated in the following experiment.

Figure 5.

Compressive strength with nano-SnO₂ at different cured ages.

Hydration heat

The cement paste hydration exothermic rate with 0.00%, 0.08%, and 0.20% dosage of nano-SnO₂ within 72 h is shown in Figure 6(a). It has been known that Portland cement hydration is an exothermic process.¹⁸ Clinker mineral can immediately dissolve in water, and 3CaO·Al₂O₃ (abbreviated as C₃A) first occurs to hydrate and form ettringite rapidly in the presence of gypsum. Therefore, the first exothermic peak appeared around the tens of minutes. After that, with the increase of the amount of AFt, the hydration rate of C₃A becomes to decrease. The hydration exothermic rates also slowed correspondingly. In the following 10 h, 3CaO·SiO₂ (abbreviated as C₃S) begins to hydrate and generate C-S-H and Ca(OH)₂ phase, accompanied by heat release, and then, the second exothermic peak appears. It can be found that with the increase of nano-SnO₂ content, the rates of hydration heat tend to be accelerated. This may be caused by the nucleation effect of nano-SnO₂, which is related to the smaller particle size of nano-SnO₂. There is a large number of small particles distributed in the matrix, which provided the nucleation of new hydration products. The hydration rate reached the highest value with the content of 0.20% nano-SnO₂. It could be found from Figure 6(b) that with the increase of nano-SnO₂ content, the total amount of heat released from cement hydration also increases, indicating that nano-SnO₂ could promote the Portland cement hydration process.

Figure 6.

(a) Hydration heat release rate and (b) hydration heat release of reference cement paste with content of nano-SnO₂.

Nanoindentation

The nanoindentation reflects the resistance of local plastic deformation ability, which is also an important mechanical performance index, and elastic modulus of the material is also reflected. To investigate the effect of nano-SnO₂ on elastic modulus of cement at 28 days, the elastic modulus contour map of the cement pastes with 0.00% and 0.08% dosage of SnO₂ is shown in Figure 7(a) and (b). It is generally believed that the elastic modulus is not higher than 50 GPa. According to the method of literature,¹⁹ the modulus of elasticity 0–13, 13–26, 26–39, and ÿҰ39 GPa can be expressed as micropore, low density (LD) C-S-H, high density (HD) C-S-H, and Ca(OH)₂. The part above 50 GPa can be regarded as a complex of unhydrated particles and hydrated products. In order to compare the effect of nano-SnO₂ on hydration structure, the zone range of 0–39 GPa is selected and studied. The interval of hardness is divided into 0–0.45, 0.45–0.83, 0.83–1.31, and 1.31–2.0 GPa,¹⁹ which can be expressed as micropore, LD C-S-H, HD C-S-H, and Ca(OH)₂, respectively. Figure 7(c) and Table 2 are the results of the ratio of C-S-H gel calculated through elastic modulus results. Results show that LD C-S-H and HD C-S-H accounted for 40% and 60% of gel, respectively, in the control samples. When 0.08% of nano-SnO₂ is added, the proportion of the ratio is 24.2% and 75.8%. The results of the ratio of C-S-H gel calculated by hardness are shown in Table 3. As can be seen in Table 3, HD C-S-H and Ca(OH)₂ were promoted to form with the addition of nano-SnO₂, especially when the production of Ca(OH)₂ was greatly increased. Through the nanoindentation result analysis of elastic modulus results and hardness, it is clear that the addition of 0.08% nano-SnO₂ can promote the generation of HD C-S-H and Ca(OH)2, which made a big contribution to the compressive strength increase.

Figure 7.

(a) Contour map of indentation on modulus in GPa (0.00%), (b) contour map of indentation on modulus in GPa (0.08%), and (c) elastic modulus distribution.

Table 2.

Interval range of hydration products of paste with different amounts of SnO₂ calculated by elastic modulus (%).

	LD C-S-H	HD C-S-H	Total
0.00	40.0	60.0	100.0
0.08	24.2	75.8	100.0

Table 3.

Interval range of hydration products of paste with different amounts of SnO₂ calculated by hardness (%).

	Micropore	LD C-S-H	HD C-S-H	Ca(OH)₂	Total
0.00	13.3	26.7	35.0	25.0	100.0
0.08	6.3	14.5	39.6	39.6	100.0

XRD

XRD analyses were used to investigate the composition of hydration products. Figure 8 illustrates the XRD analysis of cement paste with 0.00%, 0.08%, and 0.20% dosage of nano-SnO₂ at 3 h, respectively. It was found that ettringite, portlandite (Ca(OH)₂), C₂S (2CaO·SiO₂), and C₃S were the major phases for all the mixes. After incorporating nano-SnO₂, XRD pattern of the hydration products still has characteristic diffraction peaks of these substances; there are no new characteristic peak and new phase compared to the control sample with 0.00% nano-SnO₂. And it can be found that when nano-SnO₂ was added, the Ca(OH)₂ peak (2θ = 18°) begins to appear, but the peak of Ca(OH)₂ (2θ = 18°) is not obvious in the control sample at 3 h. Combined with the “Hydration heat ”section, it indicates that the addition of nano-SnO₂ can promote the formation of Ca(OH)₂, illustrating that nano-SnO₂ can promote the early hydration of cement. In order to further study the properties of cement, more tests need to be done.

Figure 8.

XRD pattern of 3 h hydration products of fly ash cement paste with different contents of nano-SnO₂.

Morphology

To further explore the role of nano-SnO₂ in enhancing the early-age mechanical properties of cement paste, morphology of cement hydration products of different age periods was observed by SEM. Figure 9(a)–(f) represents the SEM images of cement paste with 0.00%, 0.08%, and 0.20% nano-SnO₂ dosage cured for 3 and 7 days. With the addition of nano-SnO₂, it could be found that the hydration product structure becomes more compact, especially in the sample with 0.08% content of nano-SnO₂ at 3 and 7 days. Based on the present research literature, nanomaterial-modified cement-based-materials generally showed three effects: nucleation effect, filling effect, and chemical function.^20–22 From the “XRD” section, XRD analysis shows that there is no new phase appearing in the sample with the addition of nano-SnO₂, that is, no chemical function observed in the cement hydration process with the addition of nano-SnO₂. And the nucleation effect of nano-SnO₂ in the crystal growth process can be obvious obtained from the “Hydration heat” section (hydration heat analysis). As we know, the structural defects affected the compressive strength; the denser the combination of hydration products, the higher the compressive strength of cement paste. And the SEM results show that the cement paste with 0.08% nano-SnO₂ presents much denser structure; thus, the compressive strength of a sample with 0.08% nano-SnO₂ was significantly increased, as shown in Figure 5.

Figure 9.

SEM micrographs of cement hydration products at 3 and 7 days with 0.00%, 0.08%, and 0.20% dosage of nano-SnO₂: (a) 0.00%, 3 days; (b) 0.08%, 3 days; (c) 0.20%, 3 days; (d) 0.00%, 7 days; (e) 0.08%, 7 days; and (f) 0.20%, 7 days.

Pore structure

The pore structures of cement hydration products have a significant effect on the compressive strength.¹⁹ Figure 10 shows the pore size distribution of cement hydration products in 3 days with 0.00%, 0.08%, and 0.20% dosage of nano-SnO₂. The specific surface area and pore structure parameter of cement hydration products at 3 days with 0.00%, 0.08%, and 0.20% dosage of nano-SnO₂ are shown in Table 4. The most available apertures of hydration products with 0.00%, 0.08%, and 0.20% dosage of nano-SnO₂ were 0.0792, 0.0636, and 0.0832 µm, respectively. With the addition of 0.08% dosage nano-SnO₂, pore size was refined and pore structure becomes denser. However, the most available aperture of cement pastes with 0.20% dosage nano-SnO₂ was larger than the sample with 0.08% and 0.00% dosage of nano-SnO₂. The surface area and cumulative pore volume of cement stone become smaller with the addition of 0.20% dosage nano-SnO₂. It could also be found in the “Hydration heat” section that the hydration speed of a sample with 0.20% dosage nano-SnO₂ was faster than the 0.08% and 0.00% dosage nano-SnO₂ in the earlier stage.

Figure 10.

Pore size distribution of cement hydration products at 3 days with 0.00%, 0.08%, and 0.20% dosage of nano-SnO₂.

Table 4.

Specific surface area and pore structure parameter of cement hydration products at 3 days with 0.00%, 0.08%, and 0.20% dosage of nano-SnO₂.

Nano-SnO₂ content (wt%)	0.00%	0.08%	0.20%
Specific surface area (m²/g)	6.6542	5.5783	5.7697
Cumulative pore volume (cm³/g)	0.0967	0.0752	0.0933
Most available pore diameter (µm)	0.0792	0.0636	0.0832

Conclusion

The effect of nano-SnO₂ on the early-age hydration of cement paste is first investigated in this study. Based on the above experimental results, the main findings of this study, which are useful information about the effect of nano-SnO₂ on the cement-based material properties, can be summarized as follows:

The early-age compressive strength of cement paste was improved by the addition of nano-SnO₂. In the case of cement paste samples incorporating nano-SnO₂, the sample with 0.08% dosage by weight of cement exhibited the largest compressive strength strain among the investigated mixes. Compared to the control sample, the compressive strength of samples at 1, 3, and 7 days with 0.08% dosage was improved by 41.4%, 4.4%, and 10.6%, respectively.

Portland cement hydration process was found to be promoted by the addition of nano-SnO₂. The total amount of heat released from cement hydration is increased with the increase of nano-SnO₂ content. There is no new phase of sample with nano-SnO₂ compared to the control sample. The addition of nano-SnO₂ can promote the generation of HD C-S-H and reduce the generation of LD C-S-H, indicating the nucleation effect of nano-SnO₂ in the crystal growth process, which is related to the compressive strength value change.

Appropriate dosage of nano-SnO₂ decreases the porosity and the most probable pore diameter. The SEM results also show that the cement paste with 0.08% nano-SnO₂ presents much denser structure, which is consistent with the macro-mechanical strength performance.

Footnotes

Acknowledgements

We also greatly appreciate Miss Syafira Cardosha, who modified the language of the manuscript.

Handling Editor: Grzegorz Golewski

Declaration of conflicting interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was financially supported by the National Natural Science Foundation of China (No. 51872137), Scientific and Technological Project of Henan Province (No. 162102310424), and Natural Science Foundation of Henan Province (No. 162300410118).

ORCID iDs

Jianping Zhu

Chunhua Feng

References

Hydration and microstructure stability of composite cement based materials. Beijing, China: Tsinghua University, 2010.

Liu

JA.

Preliminary study on nano-materials reinforced cementitious composite. Dalian, China: Dalian University of Technology, 2012.

Guo

Cui

Wang

et al . Nano amorphous C-S-H gel particles and its structure characterize. Bull Chin Ceram Soc 2012; 31: 531–534.

Shi

Khayat

et al . Effects of different nanomaterials on hardening and performance of ultra-high strength concrete (UHSC). Cement Concrete Comp 2016; 70: 24–34.

Hou

Zhou

et al . Influence of SiO₂@PMHS on the water absorption of cement mortar as a surface treatment agent. In: International conference on the durability of concrete structures, Shenzhen, China, 30 June–1 July 2016. West Lafayette, IN: Purdue Scholarly Publishing Services.

Cai

Hou

Cheng

et al . The effects of nanoSiO₂ on the properties of fresh and hardened cement-based materials through its dispersion with silica fume. Constr Build Mater 2017; 148: 770–780.

Barbhuiya

Mukherjee

Nikraz

Effects of nano-Al₂O₃ on early-age microstructural properties of cement paste. Constr Build Mater 2014; 52: 189–193.

Zhang

Cheng

Hou

et al . Influences of nano-TiO₂ on the properties of cement-based materials: hydration and drying shrinkage. Constr Build Mater 2015; 81: 35–41.

Yin

Zhu

Guan

et al . Effect of MXene (nano-Ti₃C₂) on early-age hydration of cement paste. J Nanomater 2015; 2015: 430578.

10.

Huang

Matsunaga

Shimanoe

et al . Nanotubular SnO₂ templated by cellulose fibers: synthesis and gas sensing. Chem Mater 2016; 17: 3513–3518.

11.

Qin

Gao

Jiang

et al . Well-aligned Nd-doped SnO₂ nanorod layered arrays: preparation, characterization and enhanced alcohol-gas sensing performance. Phys Chem Chem Phys 2016; 18: 5537–5549.

12.

Tsuruta

Itoh

Mikami

et al . Trial of an all-ceramic SnO₂ gas sensor equipped with CaCu₃Ru₄O₁₂ heater and electrode. Materials 2018; 11: 981.

13.

Liu

Zhang

New insight into gas sensing performance of nanoneedle-assembled and nanosheet-assembled hierarchical SnO₂ structures. Mater Lett 2016; 176: 9–12.

14.

Mazloom

Ghodsi

Golmojdeh

Synthesis and characterization of vanadium doped SnO₂ diluted magnetic semiconductor nanoparticles with enhanced photocatalytic activities. J Alloy Compd 2015; 639: 393–399.

15.

Shang

Zhang

Yang

et al . Effect of graphene oxide on the rheological properties of cement pastes. Constr Build Mater 2015; 96: 20–28.

16.

Wei

Qin

et al . Co-effects of graphene oxide sheets and single wall carbon nanotubes on mechanical properties of cement. J Phys Chem Solids 2015; 85: 39–43.

17.

Liu

Zhang

Jiang

Continuous tracking of the relationship between resistivity and pore structure of cement pastes. Constr Build Mater 2014; 53: 26–31.

18.

Taylor

HFW

. Cement chemistry. Cambridge, MA: Academic Press, 1997.

19.

Constantinides

Ulm

FJ.

The nanogranular nature of C–S–H. J Mech Phys Solids 2007; 55: 64–90.

20.

Bahmani

Huat

BBK

Asadi

et al . Stabilization of residual soil using SiO₂ nanoparticles and cement. Constr Build Mater 2014; 64: 350–359.

21.

Chuah

Pan

Sanjayan

et al . Nano reinforced cement and concrete composites and new perspective from graphene oxide. Constr Build Mater 2014; 73: 113–124.

22.

Hui

WH.

Study on effect of nano-CaCO₃ on cement based materials and mechanism of action. Harbin, China: Harbin Institute of Technology, 2013.

Effect of nano-SnO 2 on early-age hydration of Portland cement paste

Abstract

Keywords

Introduction

Materials and experiments

Materials

Mix proportion and experimental methods

Mix proportion

Rheological measurements

Compressive strength

Hydration analysis

Nanoindentation measurement

X-ray diffraction analysis

Scanning electron microscope test

Mercury intrusion porosimetry test

Results and discussion

Rheological property

Compressive strength

Hydration heat

Nanoindentation

XRD

Morphology

Pore structure

Conclusion

Footnotes

Acknowledgements

Declaration of conflicting interests

Funding

ORCID iDs

References