Cement-based Piezoelectric Composites Research Articles

Early Performance Evolution Tracking and Monitoring for Cement-based Piezoelectric Composites under Multiple Curing Conditions

Early Performance Evolution Tracking and Monitoring for Cement-based Piezoelectric Composites under Multiple Curing Conditions

Design and manufacture of lead-free eco-friendly cement-based piezoelectric composites achieving superior piezoelectric properties for concrete structure applications

A complex-ion doping strategy fabricates lead-free BCZT ceramic. The excellent properties (d33 ∼ 577 pC/N, Kt ∼ 52%, TC ∼ 110 °C, d∗33 ∼ 620 pm/V, εr ∼ 1820, tanδ ∼ 0.02) were obtained in BCZT ceramic. The in-situ Raman spectroscopy and PFM were conducted to reveal the mechanisms for the superior properties achieved. BCZT ceramics were manufactured for cement-based piezoelectric composites, including 0–3, 2-2 and 1–3 types. 0–3 type (50% BCZT) showed the properties (d33 ∼ 46 pC/N, εr ∼ 310 and Kt ∼ 18.1%). 2-2 and 1–3 types exhibited good piezoelectric properties (d33 ∼ 285 pC/N, εr ∼ 720 and Kt ∼ 33.4% for 2-2 type; d33 ∼ 238 pC/N, εr ∼ 485 and Kt ∼ 29.5% for 1–3 type). Temperature-dependent electrical properties of BCZT-cement composites were systematically explored. Additionally, BCZT ceramic was designed and fabricated for PCD vibration energy harvesting. The output voltage (∼4.9 V) and output power (∼2.4 mW) were obtained. This work underpins the significance of lead-free BCZT ceramic and cement-based piezoelectric composites, and promotes their applications in smart structures.

Construction of 2-2 Type Cement-Based Piezoelectric Composites’ Mechanic–Electric Relationship Based on Strain Rate Dependence

It has been found that the mechanic-electric response of cement-based piezoelectric composites under impact loading is nonlinear. Herein, we prepared a 2-2 cement-based piezoelectric composite material using cutting, pouring, and re-cutting. Then, we obtained the stress-strain and stress-electric displacement curves for this piezoelectric composite under impact loading using a modified split Hopkinson pressure bar (SHPB) experimental apparatus and an additional electrical output measurement system. Based on the micromechanics of the composite materials, we assumed that damage occurred only in the cement paste. The mechanical response relationship of the piezoelectric composite was calculated as the product of the viscoelastic constitutive relationship of the cement paste and a constant, where the constant was determined based on the reinforcement properties of the mechanical response of the piezoelectric composite. Using a modified nonlinear viscoelastic Zhu-Wang-Tang (ZWT) model, we characterized the stress-strain curves of the piezoelectric composite with different strain rates. The dynamic sensitivity and stress threshold of the linear response of the samples were calibrated and fitted. Thus, a mechanic-electric response equation was established for the 2-2 type cement-based piezoelectric composite considering the strain rate effects.

Effect of graphene on the piezoelectric properties of cement-based piezoelectric composites

Two types of graphene, namely, graphene oxide (GO) and multilayer graphene nanoplatelets (GNPs), were added to a 0–3-type cement-based piezoelectric composite to investigate the piezoelectric properties of the composite. The aforementioned composite contained a cement matrix and lead zirconate titanate inclusions, each of which accounted for 50% of the composite volume. The results obtained by using ultrasonic vibrations and a hydrometer indicated that the optimal dispersion times of GO in pure water and GNPs in ethanol were 30 and 15 min, respectively. The addition of GO to the aforementioned composite decreased the composite’s relative permittivity (εr) and increased dielectric loss and electrical resistance, resulting in difficulties in poling and poor polarization efficiency. GO is not conducive to improving the piezoelectric properties (piezoelectric charge coefficient d33, piezoelectric voltage coefficient g33, εr, and electromechanical coupling coefficient kt) of piezoelectric composites. GNP addition to cement can reduce the resistivity and increase dielectric loss of cement composites. The composites with a lower resistance can be polarized easily. The appropriate addition of GNPs can improve the polarization efficiency, thereby enhancing the piezoelectric properties of cementitious composites. In this study, the optimal addition of GNPs was 0.3%. Wet-mixing of GNP-containing cementitious composites with a superplasticizer in ethanol can further improve the piezoelectric properties of this composite (d33 = 123 pC/N, g33 = 22.6 ×10−3 V·m/N, εr = 615, and kt = 20.2%). The GNP-containing cementitious composite mixed with a superplasticizer exhibited a high kt; thus, this composite has potential for use as a green energy material.

Study on Durability and Piezoresistivity of Cement-Based Piezoelectric Materials Mixed with Carbon Fiber and Iron Tailings under Salt-Freezing Erosion

Under the complex working conditions in cold areas, in order to achieve health monitoring of engineering structures, carbon fiber and iron tailings sand were added to ordinary cement-based materials to prepare cement-based piezoelectric composites, and the deterioration of their pressure-sensitive properties and mechanical properties under the action of the sulfate-freeze-thaw cycle was studied. Six groups of specimens and a set of benchmark specimens were prepared according to different contents of carbon fiber and iron tailings sand, and the specimens of each group were analyzed qualitatively and quantitatively after 50, 100, and 150 freeze-thaw cycles. Based on the external damage analysis, it was concluded that with the increase in the number of freeze-thaw cycles, the apparent morphology of the specimens in each group continued to deteriorate. After 150 freeze-thaw cycles, the addition of a certain proportion of carbon fiber and iron tailings can improve the compactness of cement-based composites, effectively inhibit the development of cracks, maintain the integrity of the apparent morphology of the specimen, and the quality loss rate of the specimen does not exceed 5%. Based on the internal damage analysis, it is concluded that the specimen mixed with carbon fiber and iron tailings has undergone the freeze-thaw cycles, and its relative dynamic elastic modulus generally shows a trend of first rising and then falling, and after 150 freeze-thaw cycles, the relative dynamic elastic modulus of C04T30 specimen is 85.5%, and its compressive strength loss rate is 20.2%, indicating that its freeze resistance is optimal. The compressive stress and resistivity change rate of each group of cement-based piezoelectric composite specimens that have not undergone freeze-thaw cycles are approximately consistent with the linear attenuation relationship. Those that have undergone 150 freeze-thaw cycles approximately conform to the polynomial attenuation relationship. The correlation coefficient between the compressive stress and the resistivity rate of the change fitting curve are all above 0.9, and the correlation is high; therefore, the deterioration of the structural mechanical properties after freeze-thaw cycles can be reflected by the resistivity change rate. After 150 freeze-thaw cycles, the pressure sensitivity coefficient of the C04T30 specimen is 0.007294, which has good pressure sensitivity. So, cement-based piezoelectric composite material can be embedded as an impedance sensor to monitor the health of engineering structures.

Effects of the Water/Cement Ratio on the Properties of 3-3 Type Cement-Based Piezoelectric Composites

In this work, 3-3 type porous lead zirconate titanate (PZT) ceramics were fabricated by incorporating particle-stabilized foams using the gel-casting method. Then, Portland cement pastes with different water/cement ratios (w/c) were cast into the porous ceramics to produce cement-based piezoelectric (PZT-PC) composites. The effects of w/c on phase structure, microscopic morphology, and electrical properties were studied. The results showed that the amount of hydrated cement products and the density of the PZT–PC composites increased with the increase of w/c from 0.3 to 0.9 and then decreased till w/c achieved a value of 1.1. Correspondingly, the values of both εr and d33 increased with the density of the PZT–PC composites, resulting in less defects and greater poling efficiency. When w/c was maintained at 0.9, the 3-3 type cement-based piezoelectric composites presented the greatest Kt value of 40.14% and the lowest Z value of 6.98 MRayls, becoming suitable for applications in civil engineering for structural health monitoring.

Mechanical, piezoelectric, and dielectric properties of a novel 0–3 γ-C2S-PZT composite

This paper investigated the effect of PZT volume, forming pressure, and polarization regime on mechanical, piezoelectric, and dielectric properties of the 0–3 γ-C2S-PZT composite. The latter two included the piezoelectric strain coefficient (d33), piezoelectric voltage coefficient (g33), and dielectric constant (εr). Experimental results indicated that the increase of PZT volume from 0 to 80% significantly increased the d33, g33, and εr from near zero to 70 pC/N, 75 × 10−3 Vm/N, and 140, respectively, due to the enhanced contact between PZT particles. The compressive strength and d33 of γ-C2S-PZT composite were enhanced by 100% and 35%, respectively, with the forming pressure increasing from 25 to 100 MPa. Further increase in pressure to 200 MPa led to the reduction in mechanical strength and piezoelectricity due to the increased porosity of the composite. The increase of polarization voltage from 1.0 to 4.0 kV/mm resulted in doubling the d33 and g33 values. Such improvement for εr was 55%. These three parameters were enhanced by 75%, 25%, and 35%, respectively, with the increase of polarization duration from 5 to 30 min. Compared to cement-based piezoelectric composite, the γ-C2S-PZT composite had 1–5.5, 1–1.2, and 1–2.5 folds greater d33, g33, and εr values, respectively. This can enable the development of a novel low-carbon γ-C2S-PZT composite with improved piezoelectric and dielectric properties, given the reduced carbon footprint and CO2-absorbing characteristics of γ-C2S.

Influence of PZT volume fraction, composite thickness and cement matrix on the performance of d15 shear mode 1–3 connectivity cement-based piezoelectric composites

In this work, we investigated the influence of PZT volume fraction, composite thickness and cement matrix on the performance of 1–3 connectivity cement-based piezoelectric composites working in d15 shear mode. Results revealed that the piezoelectric strain coefficient d15 and the relative dielectric coefficient εr decrease with the decrease of the PZT volume fraction and increase with the increase of the composite thickness. The piezoelectric strain coefficient d15 of the composite specimens with Phosphoaluminate cement (PALC) matrix is the largest, followed by Sulfoaluminate cement (SAC) matrix and Portland cement (PC) matrix. The relative dielectric coefficient εr of the composite specimens with PC matrix is the largest, followed by PALC matrix and SAC matrix. The piezoelectric voltage factor g15 increases with the decrease of the PZT volume fraction and decreases with the increase of the composite thickness. The piezoelectric voltage factor g15 of the composite specimens with PC matrix is the smallest, and the values of specimens with SAC matrix and PALC matrix are very close.

The Influence of Slag/Fly Ash Ratio and Sodium Silicate Modulus on the Properties of 1-3-2 Alkali-Based Piezoelectric Composite.

In this paper, a comprehensive experimental investigation on the effect of the slag-to-fly ash ratio (hereafter referred to as SL/FA) and sodium silicate modulus on the properties of a 1-3-2 piezoelectric composite was carried out. The influence of the SL/FA ratio on various properties was initially investigated. Compared with other specimens, specimens with SL/FA = 40%:60% had the highest electromechanical coupling coefficient (Kt = 77.67%, Kp = 71%). Therefore, the specimen with SL/FA = 40%:60% was chosen to explore the effect of the sodium silicate modulus. Additionally, the specimen with SL/FA = 40%:60% and a sodium silicate modulus of 1.3 had the best electromechanical conversion efficiency with Kt = 75.68% and Kp = 75.95%. The 1-3-2 alkali-based piezoelectric composite proved to have the characteristics of a low cost, optimal piezoelectric and mechanical properties, higher tunability, and better compatibility with concrete. It is a potential alternative to cement-based piezoelectric composites and may be widely utilized to monitor the health of concrete structures.

Tracking and Monitoring of Performance Evolution of 0-3 Cement-Based Piezoelectric Composites Under Different Curing Conditions

Tracking and Monitoring of Performance Evolution of 0-3 Cement-Based Piezoelectric Composites Under Different Curing Conditions

Effect of Graphene on the Piezoelectric Properties of Cement-Based Piezoelectric Composites

Effect of Graphene on the Piezoelectric Properties of Cement-Based Piezoelectric Composites

Dynamic Response of Electro-Mechanical Properties of Cement-Based Piezoelectric Composites

By employing ordinary Portland cement as a matrix and PZT-5H piezoelectric ceramic as the functional body, 1-3 and 2-2 cement-based piezoelectric composites were prepared. Quasi-static compression tests were performed along with dynamic impact loading tests to study the electro-mechanical response characteristics of 1-3 and 2-2 cement-based piezoelectric composites. The research results show that both composites exhibit strain rate effects under quasi-static compression and dynamic impact loading since they are strain-rate sensitive materials. The sensitivity of the two composites has a non-linear mutation point: in the quasi-static state, the sensitivity of 1-3 and 2-2 composites is 157 and 169 pC/N, respectively; in the dynamic state, the respective sensitivity is 323 and 296 pC/N. Although the sensitivity difference is not significant, the linear range of the 2-2 composite is 24.8% and 61.3% larger than that of the 1-3 composite under quasi-static compression and dynamic impact loading, respectively. Accordingly, the 2-2 composite exhibits certain advantages as a sensor material, irrespective of whether it is subjected to quasi-static or dynamic loading.

Study on dynamic properties of 1–3 cement-based piezoelectric composites

In this paper, Hopkinson compression bar technology is used to test the related properties of 1–3 cement-based piezoelectric composites under dynamic load. The research results prove that the stress and electric displacement of 1–3 cement-based piezoelectric composites have similar changing trends under dynamic action, that is, the response state of mechanical and electrical properties of the specimens is good. At the same time, due to the action of force, the phenomenon of electrical domain deflection and depolarization occurs, and the piezoelectric properties of the material also weaken with the increase of the number of loading.

Dielectric and piezoelectric behavior of PVDF-modified 3-3 type cement-based piezoelectric composites

In this research, 3–3 type cement-based piezoelectric composites were prepared by casting Portland cement paste in porous lead zirconate titanate (PZT) ceramics, then the polyvinylidene fluoride (PVDF) of N-methylpyrrolidone solvent with concentration of 50–200 mg ml−1 was utilized to modify the lead zirconate titanate-Potland cement (PZT-PC) composites. The effects of PVDF concentration on the density, microstructure, dielectric, piezoelectric and electromechanical properties were studied. The results indicate that the density of PZT-PC composites increased gradually with PVDF concentration for the increasing combined weight of PVDF with the composites. The introduction of PVDF has also contributed to the reduction of leakage current during the poling and testing process, which led to increased relative permittivity ϵ r and longitudinal piezoelectric strain coefficient d 33, while the dielectric loss tanδ and longitudinal piezoelectric voltage coefficient g 33 demonstrated an opposite changing trend. The thickness electromechanical coupling factor K t of composites increased with the concentration of PVDF solution. The acoustic impedance (Z) of PVDF modified PZT-PC composites ranged from 6.89 to 7.65 MRayls, making it suitable for applications in the health monitoring of civil engineering.

Roles of CSH gel in the microstructure and piezoelectric properties variation of cement-based piezoelectric ceramic composite

The microstructures of cement-based piezoelectric composites with Portland cement (hydrated/fresh cement powder) as the matrix phase and lead zirconate titanate (PZT) particles as the functional phase are characterized to illustrate the effect of calcium-silicate-hydrate (CSH) on the binding behavior between two phases before and after polarization. Piezoelectric properties variation are traced to evaluate the aging effect. Results show the CSH structure change from nano-flocculent/fibrous to ellipsoid after polarization. The piezoelectric strain factor of the hydrated cement-based composite with low hydration capacity shows a decreasing trend with age due to the insufficient binding between the CSH and PZT particles, while that of the fresh cement-based composite shows an opposite tendency. This investigation also reveals the influence of polarization on the CSH gel structure, promoting the further understanding of binding behavior between the CSH and PZT for the piezoelectric performance variation during the non-polarization process.

Fabrication and properties of 3-3 type PZT-ordinary Portland cement composites

In this study, porous lead zirconate titanate (PZT) ceramics with porosity ranging from 46.4% to 82.3% were produced by the gel casting technology of particle-stabilized ceramic foams with the solid loading of 5–25 vol%, then the Portland cement paste was cast in porous PZT ceramics with continuous vibration to fabricate 3-3 type cement-based piezoelectric composites. The microstructure, dielectric, piezoelectric, and electromechanical coupling properties of the composites were characterized. With the increase in initial solid loading of PZT slurry, both the porosity, open porosity and pore size of porous PZT ceramics decreased correspondingly, which have prevented the filling of cement paste into the porous ceramics and led to the increment of PZT content in the composites. Increase in the PZT content contributed to the relative permittivity (εr) and longitudinal piezoelectric strain coefficient (d33), and a resultant reduction in piezoelectric voltage coefficient (g33). The prepared composites possessed a maximal thickness electromechanical coupling coefficient (Kt) value of 41.22%, higher than that of planar electromechanical coupling coefficient (Kp), indicating enhanced thickness mode oscillations of the composite. With the increase in PZT volume fraction, the PZT-cement composites turned from typical 3-3 structure to appoximate sandwich structure gradually, leading to more energy loss during electromechanical process and obvious decrease of the mechanical quality factor (Qm). The acoustic impedance (Z) of specimens ranged from 6.69 to 8.27 MRayls, close to that of cement materials (∼10 MRayls), making them promising candidate for application in civil engineering.

Influence of hydration capacity for cement matrix on the piezoelectric properties and microstructure of cement-based piezoelectric ceramic composites

Cement-based piezoelectric ceramic composite (CPC) is the potential sensing element for long-term structural health monitoring due to its excellent durability and compatibility. In this study, the piezoelectric properties and microstructure of CPCs with the cement (fresh/hydrated cement powder) as matrix phase and lead zirconate titanate (PZT) particles utilized as functional phase are fabricated and characterized to investigate the effect of hydration capacity of the matrix on the piezoelectric properties. Piezoelectric properties testing and microstructure analysis are performed to evaluate the testing samples. Results show that the piezoelectric strain factor of the hydrated cement-based composite shows a decreasing trend with age, while that of the fresh cement-based composite shows an opposite tendency. The morphology and product structure of the composite after curing and polarization are tremendously different. After polarization, the calcium-silicate-hydrate (CSH) structure changes from fibrous to nano-ellipsoid. The interfacial transition zone of the fresh cement-based composite after curing and polarization is different from the hydrated cement-based composite due to the insufficient binding between CSH and PZT.

Cement-Based Piezoelectric Ceramic Composites for Sensing Elements: A Comprehensive State-of-the-Art Review.

Compatibility, a critical issue between sensing material and host structure, significantly influences the detecting performance (e.g., sensitive, signal-to-noise ratio) of the embedded sensor. To address this issue in concrete-based infrastructural health monitoring, cement-based piezoelectric composites (piezoelectric ceramic particles as a function phase and cementitious materials as a matrix) have attracted continuous attention in the past two decades, dramatically exhibiting superior durability, sensitivity, and compatibility. This review paper performs a synthetical overview of recent advances in theoretical analysis, characterization and simulation, materials selection, the fabrication process, and application of the cement-based piezoelectric composites. The critical issues of each part are also presented. The influencing factors of the materials and fabrication process on the final performance of composites are further discussed. Meanwhile, the application of the composite as a sensing element for various monitoring techniques is summarized. Further study on the experiment and simulation, materials, fabrication technique, and application are also pointed out purposefully.

Study of Piezoresistive Behavior of Smart Cement Filled with Graphene Oxide.

A cement-based piezoelectric composite, modified by graphene oxide (GO), was prepared to study piezoresistive capacity. The testing confirms that GO is more effective than other carbon nanomaterials at improving piezoresistive sensitivity of cement-based composites, because the content of GO in cement paste was much lower than other carbon nanomaterials used in previously published research. Further investigation indicates that the addition of GO significantly improved the stability and repeatability for piezoresistive capacity of cement paste under cycle loads. Based on experiment results, the piezoresistive sensitivity of this composite depended on GO content, water-to-cement weight ratio (w/c) and water-loss rate, since the highest piezoresistive gauge factor value (GF = 35) was obtained when GO content was 0.05 wt.%, w/c was 0.35 and water-loss rate was 3%. Finally, microstructure analysis confirmed that conductivity and piezoresistivity were achieved through a tunneling effect and by contacting conduction that caused deformation of GO networks in the cement matrix.

Cement-based piezoelectric composite sensor designed for charactering the three-dimensional stress state in concrete

We reported a sensor, designed based on the specific working modes of piezoelectric, to characterize the three-dimensional (3-D) stress state in concrete. The sensor contains 6 piezoelectric elements: 3 elements working in normal mode to measure the normal stress, and 3 elements working in shear mode to measure the shear stress. Cement-based piezoelectric composite, fabricated by cutting-filling method, was used to fabricate the sensor, as it has better mechanical compatibility with concrete than piezoelectric ceramics. By embedding the sensor into a cement mortar column, we systematically characterized its performance under dynamic uniaxial load from 3.0 MPa to 7.5 MPa with frequency from 1 Hz to 20 Hz. Results demonstrate that the sensor can measure the 3-D stress state in concrete well, and has good linearity, high sensitively, and excellent working bandwidth. The cross sensitivities of the sensor were also calculated and discussed.