Self-sensing performance of cementitious composites with electrostatic self-assembly carbon nanotube/titanium dioxide
-
摘要: 基于体积排阻效应，采用导电性能优异的碳纳米管(CNT)和微尺度二氧化钛(TiO2)通过静电自组装技术制得CNT/TiO2复合填料并将其与水泥基材料复合，有望发展具有优异自感知性能的水泥基复合材料。为此，对静电自组装CNT/TiO2水泥基复合材料的电学性能及加载幅值、加载速率和含水率等不同环境条件下的自感知性能进行了研究，并分析了静电自组装CNT/TiO2复合填料对水泥基复合材料电学性能和自感知性能的改善机制，最后对比了不同环境因素对自感知性能的影响规律。研究结果表明，当CNT的体积掺量为2.40vol%时，静电自组装CNT/TiO2水泥基复合材料的电阻率降低了99.8%。在循环压缩荷载作用下，静电自组装CNT/TiO2水泥基复合材料的最大电阻率变化率达到49.23%，应力灵敏度和应变灵敏度分别达到8.21%/MPa和812。当加载幅值、加载速率及含水率不同时，静电自组装CNT/TiO2水泥基复合材料均表现出优异的感知性能，其中灵敏度随着加载幅值和加载速率的增加分别降低和提高，但最大电阻率变化率、应力灵敏度和应变灵敏度均随着含水率降低而提高。50℃全烘干状态时，静电自组装CNT/TiO2水泥基复合材料的最大电阻率变化率、应力和应变灵敏度分别达到74.36%、12.39%/MPa和1350。不同环境因素对静电自组装CNT/TiO2水泥基复合材料自感知性能的影响大小顺序为：含水率、加载幅值和加载速率。Abstract: Carbon nanotube/titanium dioxide (CNT/TiO2) composite fillers were obtained using electrostatic self-assembly technology with combining conductive CNT and microscale TiO2 based on excluded volume effect. And then, cementitious composites with electrostatic self-assembly CNT/TiO2 was used to develop cementitious composites with excellent self-sensing performance. The electrical properties of cementitious composites with electrostatic self-assembly CNT/TiO2 were investigated. At the same time, the effects of different environmental conditions on self-sensing performance also were studied including loading amplitudes, loading rates and water content. Additionally, modification mechanisms of electrostatic self-assembly CNT/TiO2 composite fillers on electrical and self-sensing performance of cementitious composites were also analyzed. Finally, the effect of different environmental factors on self-sensing performance were compared by radar chart. The results show that electrical resistivity of cementitious composites with electrostatic self-assembly CNT/TiO2 is decreased by 99.8% when the volume content of CNT is 2.40vol%. Its maximum fractional change in resistivity is up to 49.23% under cyclic compression. Meanwhile, its stress sensitivity and strain sensitivity can reach 8.21%/MPa and 812, respectively. The cementitious composites with electrostatic self-assembly CNT/TiO2 present excellent self-sensing performance under different loading amplitudes, loading rates and water content. The sensitivities decrease with increasing of the loading amplitudes but increase with increasing of loading rates. In addition, the maximum fractional change in resistivity, stress and strain sensitivities increase with the decreasing of the water content. The maximum fractional change in resistivity, stress sensitivity and strain sensitivity of cementitious composites with electrostatic self-assembly CNT/TiO2 can reach 74.36%, 12.39%/MPa and 1350 under full drying at 50℃, respectively. The radar chart demonstrates that the important orders of the different environmental factors effect on self-sensing performance is water content, loading amplitudes and loading rates.
-
图 1 静电自组装碳纳米管(CNT)/TiO2复合填料的示意图 (a) 和SEM图像 (b)
Figure 1. Schematic diagram (a) and SEM image (b) of electrostatic self-assembly carbon nanotube (CNT)/TiO2 composite fillers
图 2 静电自组装CNT/TiO2水泥基复合材料的制备流程
Figure 2. Fabrication process of cementitious composite with electrostatic self-assembly CNT/TiO2
图 3 静电自组装CNT/TiO2水泥基复合材料的电阻测试系统照片
Figure 3. Photographs on electrical resistivity measurement systems of cementitious composites with electrostatic self-assembly CNT/TiO2
图 4 静电自组装CNT/TiO2水泥基复合材料的自感知性能测试过程
Figure 4. Self-sensing performance testing process of cementitious composites with electrostatic self-assembly CNT/TiO2
图 5 空白水泥基材料和CNT/TiO2水泥基复合材料在不同龄期下的直流电阻率
Figure 5. DC electrical resistivity of cementitious composites without and with CNT/TiO2 at different age
图 6 空白水泥基材料和CNT/TiO2水泥基复合材料在不同龄期下的交流电阻率
Figure 6. AC electrical resistivity of cementitious composites without and with CNT/TiO2 at different age
图 7 CNT/TiO2水泥基复合材料的导电机制示意图
Figure 7. Schematic diagram of conduction mechanism of cementitious composites with CNT/TiO2
图 8 CNT/TiO2水泥基复合材料的EDS (a) 和SEM图像 ((b), (c))
Figure 8. EDS (a) and SEM ((b), (c)) images of cementitious composites with CNT/TiO2
图 9 空白水泥基材料在循环荷载为6 MPa作用下的压应力 (a)、应变 (b) 和电阻率变化率
Figure 9. Compressive stress (a), strain (b) and fractional change in resistivity of cementitious composites without CNT/TiO2 under repeated compressive loading with stress amplitude of 6 MPa
图 10 CNT/TiO2水泥基复合材料在循环荷载为6 MPa作用下的压应力 (a)、应变 (b) 和电阻率变化率(FCR)
Figure 10. Compressive stress (a), strain (b) and fractional change in resistivity (FCR) of cementitious composites with CNT/TiO2 under repeated compressive loading with stress amplitude of 6 MPa
图 11 CNT/TiO2水泥基复合材料压应力 (a)、应变 (b) 与FCR的试验数据和拟合函数
Figure 11. Relationship between compressive stress (a) , strain (b) and FCR of cementitious composites with CNT/TiO2 in experimental data and fitting curve
图 12 CNT/TiO2水泥基复合材料在循环荷载为4 MPa、6 MPa和8 MPa时的压应力 (a)、应变 (b) 和FCR
Figure 12. Compressive stress (a), strain (b) and FCR of cementitious composites with CNT/TiO2 under compressive stress amplitudes of 4 MPa, 6 MPa and 8 MPa
图 13 CNT/TiO2水泥基复合材料在加载速率为0.4 mm/min、0.6 mm/min和0.8 mm/min时的压应力 (a)、应变 (b) 和电阻率变化率
Figure 13. Compressive stress (a), strain (b) and fractional change in resistivity of cementitious composites with CNT/TiO2 under loading rates of 0.4 mm/min, 0.6 mm/min and 0.8 mm/min
图 14 CNT/TiO2水泥基复合材料在循环荷载为6 MPa和50℃烘24 h时的压应力 (a)、应变 (b) 和电阻率变化率
Figure 14. Compressive stress (a), strain (b) and FCR of cementitious composites with CNT/TiO2 under drying at 50℃ for 24 h and repeated compressive loading with stress amplitude of 6 MPa
图 15 CNT/TiO2水泥基复合材料在循环荷载为6 MPa和50℃全烘干状态时的压应力 (a)、应变 (b) 和电阻率变化率
Figure 15. Compressive stress (a), strain (b) and FCR of cementitious composites with CNT/TiO2 under full drying at 50℃ and repeated compressive loading with stress amplitude of 6 MPa
图 16 空白水泥基材料和CNT/TiO2水泥基复合材料在单调加载下的压应力 (a)、应变 (b) 和FCR
Figure 16. Compressive stress (a), strain (b) and FCR of cementitious composites without and with CNT/TiO2 under monotonic loading
图 17 CNT/TiO2水泥基复合材料在不同环境因素下的分析：(a) 雷达图；(b) 封闭区域面积
Figure 17. Analysis under different environmental factors of cementitious composites with CNT/TiO2: (a) Radar chart; (b) Enclosed areas
表 1 静电自组装CNT/TiO2复合填料的主要性质
Table 1. Main properties of electrostatic self-assembly CNT/TiO2 composite fillers
Properties Values Mass ratio of CNT∶TiO2 20∶80 Resistivity of CNT/TiO2 composite fillers /(Ω∙cm) <2 Density of CNT/(g∙cm−3) 2.1 CNT purity/wt% >90 Outer diameter of CNT/nm >50 Inner diameter of CNT/nm 5-15 Length of CNT/μm 10-20 Special surface area of CNT/(m2∙g−1) >60 
下载: 导出CSV
表 2 静电自组装CNT/TiO2水泥基复合材料的配合比
Table 2. Mix proportion of cementitious composite with electrostatic self-assembly CNT/TiO2
Specimen code Binder CNT/TiO2/vol%
(CNT/vol%)Water Sand SP/wt% Cement Silica fume 0.00vol%CNT 0.9 0.1 0.00
(0.00)0.4 1.5 0.2 2.40vol%CNT 0.9 0.1 7.17
(2.40)0.4 1.5 0.2 Note: SP—Superplasticizer.
下载: 导出CSV
表 3 CNT或CNT复合填料水泥基复合材料的电阻率对比
Table 3. Comparison of electrical resistivity of cementitious composites with CNT or CNT composite fillers
下载: 导出CSV
表 4 循环荷载为6 MPa时CNT/TiO2水泥基复合材料的自感知性能评价指标
Table 4. Self-sensing performance evaluation indexes of cementitious composites with CNT/TiO2 under repeated compressive loading with stress amplitude of 6 MPa
Specimen code Maximum
FCR/%Stress
sensitivity/
(%∙MPa−1)Strain
sensitivity0.00vol%CNT 0.00 0.00 0 2.40vol%CNT 49.23 8.21 812 Note: FCR—Fractional change in resistivity.
下载: 导出CSV
表 5 CNT或CNT复合填料水泥基复合材料在循环压缩荷载作用下的FCR、SE和SA对比
Table 5. Comparison of FCR, SE and SA of cementitious composites with CNT or CNT composite fillers under repeated compressive loading
Type CNT content Maximum FCR/% SE/
(%∙MPa−1)SA Ref. CNT/TiO2 2.40vol% 49.23 8.210 812.0 This paper CNT/NCB 0.86vol% 6.80 1.650 200.0 [33] 0.96vol% 16.00 2.667 — [22] CNT 1.70vol% 19.31 1.930 — [29] 1.31vol% — 1.470 132.0 [34] 5.10wt% — 2.870 748.0 [35] 1.00wt% 21.01 — 34.0 [36] 0.50wt% 0.82 0.052 10.6 [31] Note: SE, SA, NCB and RF—Stress sensitivity, strain sensitivity, nano carbon black and references, respectively.
下载: 导出CSV
表 6 体积排阻效应对水泥基复合材料中CNT掺量的影响
Table 6. Effect of excluded volume effect on CNT content of cementitious composites
CNT content
/vol%Effective CNT content/vol% Increase of CNT content/% 2.40 2.52 5.00
下载: 导出CSV
表 7 CNT/TiO2水泥基复合材料的稳健标准误回归结果
Table 7. Results of robust standard error regression of cementitious composites with CNT/TiO2
y Model 1 Model 2 x1 x12 x2 x22 Coefficient −16.79713 1.84126 −0.15315 1.461×10−4 Robust standard error 0.5250 0.10431 0.00280 5.34×10−6 t −31.99 17.65 −54.70 27.38 p＞|t| 0.000 0.000 0.000 0.000 F(2, 601) 6100.06 21217.88 prob＞F 0.0000 0.0000 R2 0.8650 0.9574 Notes: y—Fractional change in resistivity; x1, x12, x2 and x22—Stress, square of stress, strain and square of strain, respectively; t—Method used to test the significance of each variable in a regression equation; p—Probability distribution; F—Method used to test the overall significance of regression equations; Model 1: y=(−16.79713 ± 0.5321)x1+(1.84126±0.11559)x12; Model 2: y=(−0.15315±0.00289 )x2+(1.46071×10−4±5.90463×10−6)x22.
下载: 导出CSV
表 8 CNT/TiO2水泥基复合材料在不同循环荷载时的自感知性能评价指标
Table 8. Self-sensing performance evaluation indexes of cementitious composites with CNT/TiO2 under different compressive stress amplitudes
Amplitude
/MPaMaximum FCR/% Stress sensitivity
/(%∙MPa−1)Strain sensitivity 4 47.10 11.78 1077 6 53.17 8.86 881 8 58.21 7.28 801
下载: 导出CSV
表 9 CNT/TiO2水泥基复合材料在不同加载速率时的自感知性能评价指标
Table 9. Self-sensing performance evaluation indexes of cementitious composites with CNT/TiO2 under different loading rates
Rate/ (mm∙min−1) Maximum FCR/% Stress sensiti-
vity/(%∙MPa−1)Strain sensitivity 0.4 50.86 8.48 842 0.6 52.02 8.67 864 0.8 52.56 8.76 876
下载: 导出CSV
表 10 CNT/TiO2水泥基复合材料在不同含水率作用下的自感知性能评价指标
Table 10. Self-sensing performance evaluation indexes of cementitious composites with CNT/TiO2 under different water content
Water
stateWater content
/%Maximum FCR/% Stress sensitivity
/(%∙MPa−1)Strain sensitivity Wet 100 49.23 8.21 812 Drying at 50℃ for 24 h 28 60.23 10.04 1035 Full drying at 50℃ 0 74.36 12.39 1350
下载: 导出CSV
-
[1] SIAHKOUHI M, RAZAQPUR G, HOULT N A, et al. Utilization of carbon nanotubes (CNTs) in concrete for structural health monitoring (SHM) purposes: A review[J]. Construction and Building Materials,2021,309:125137. doi: 10.1016/j.conbuildmat.2021.125137 [2] HAN B G, DING S Q, YU X. Intrinsic self-sensing concrete and structures: A review[J]. Measurement,2015,59:110-128. doi: 10.1016/j.measurement.2014.09.048 [3] CHUNG D D L. Self-sensing concrete: From resistance-based sensing to capacitance-based sensing[J]. International Journal of Smart and Nano Materials,2021,12(1):1-19. doi: 10.1080/19475411.2020.1843560 [4] WANG Y Y, ZHANG L Q. Development of self-sensing cementitious composite incorporating hybrid graphene nanoplates and carbon nanotubes for structural health monitoring[J]. Sensors and Actuators A: Physical,2022,336:113367. doi: 10.1016/j.sna.2022.113367 [5] 欧进萍, 关新春, 李惠. 应力自感知水泥基复合材料 及其传感器的研究进展[J]. 复合材料学报, 2006(4):1-8. doi: 10.3321/j.issn:1000-3851.2006.04.001OU Jinping, GUAN Xinchun, LI Hui. State-of-the-art of stress-sensing cement composite material and sensors[J]. Acta Materiae Compositae Sinica,2006(4):1-8(in Chinese). doi: 10.3321/j.issn:1000-3851.2006.04.001 [6] TENG F, LUO J L, GAO Y B, et al. Piezoresistive/ piezoelectric intrinsic sensing properties of carbon nanotube cement-based smart composite and its electromechanical sensing mechanisms: A review[J]. Nanotechnology Reviews,2021,10(1):1873-1894. doi: 10.1515/ntrev-2021-0112 [7] CHEN P W, CHUNG D D L. Carbon fiber reinforced concrete for smart structures capable of non-destructive flaw detection[J]. Smart Materials and Structures,1993,2(1):22-30. doi: 10.1088/0964-1726/2/1/004 [8] TEOMETE E. Transverse strain sensitivity of steel fiber reinforced cement composites tested by compression and split tensile tests[J]. Construction and Building Materials,2014,55:136-145. doi: 10.1016/j.conbuildmat.2014.01.016 [9] LE H V, LEE D H, KIM D J. Effects of steel slag aggregate size and content on piezoresistive responses of smart ultra-high-performance fiber-reinforced concretes[J]. Sensors and Actuators A: Physical,2020,305:111925. doi: 10.1016/j.sna.2020.111925 [10] 黄世峰, 徐东宇, 徐荣华, 等. 碳纤维/水泥基复合材料微观结构及机敏特性[J]. 复合材料学报, 2006, 23(4):95-99. doi: 10.3321/j.issn:1000-3851.2006.04.017HUANG Shifeng, XU Dongyu, XU Ronghua, et al. Microcosmic and smart properties of carbon fiber cement-based composites[J]. Acta Materiae Compositae Sinica,2006,23(4):95-99(in Chinese). doi: 10.3321/j.issn:1000-3851.2006.04.017 [11] HAN B G, ZHANG L Q, ZENG S Z, et al. Nano-core effect in nano-engineered cementitious composites[J]. Composites Part A: Applied Science and Manufacturing,2017,95:100-109. doi: 10.1016/j.compositesa.2017.01.008 [12] DANOGLIDIS P A, KONSTA-GDOUTOS M S, GDOUTOS E E, et al. Strength, energy absorption capability and self-sensing properties of multifunctional carbon nanotube reinforced mortars[J]. Construction and Building Materials,2016,120:265-274. doi: 10.1016/j.conbuildmat.2016.05.049 [13] ÇELIK D N, YıLDıRıM G, AL-DAHAWI A, et al. Self-monitoring of flexural fatigue damage in large-scale steel-reinforced cementitious composite beams[J]. Cement and Concrete Composites,2021,123:104183. doi: 10.1016/j.cemconcomp.2021.104183 [14] CASTAÑEDA-SALDARRIAGA D L, ALVAREZ-MONTOYA J, MARTÍNEZ-TEJADA V, et al. Toward structural health monitoring of civil structures based on self-sensing concrete nanocomposites: A validation in a reinforced-concrete beam[J]. International Journal of Concrete Structures and Materials,2021,15(1):99-116. [15] 施韬, 朱敏, 李泽鑫, 等. 碳纳米管改性水泥基复合材料的研究进展[J]. 复合材料学报, 2018, 35(5):1033-1049. doi: 10.13801/j.cnki.fhclxb.20180328.003SHI Tao, ZHU Min, LI Zexin, et al. Review of research progress on carbon nanotubes modified cementitious composites[J]. Acta Materiae Compositae Sinica,2018,35(5):1033-1049(in Chinese). doi: 10.13801/j.cnki.fhclxb.20180328.003 [16] SINDU B S, SASMAL S. Properties of carbon nanotube reinforced cement composite synthesized using different types of surfactants[J]. Construction and Building Materials,2017,155:389-399. doi: 10.1016/j.conbuildmat.2017.08.059 [17] GUAN X C, BAI S, LI H, et al. Mechanical properties and microstructure of multi-walled carbon nanotube-reinforced cementitious composites under the early-age freezing conditions[J]. Construction and Building Materials,2020,233:117317. doi: 10.1016/j.conbuildmat.2019.117317 [18] SIKORA P, ABD ELRAHMAN M, CHUNG S Y, et al. Mechanical and microstructural properties of cement pastes containing carbon nanotubes and carbon nanotube-silica core-shell structures, exposed to elevated temperature[J]. Cement and Concrete Composites,2019,95:193-204. doi: 10.1016/j.cemconcomp.2018.11.006 [19] ZHANG L Q, ZHENG Q F, DONG X F, et al. Tailoring sensing properties of smart cementitious composites based on excluded volume theory and electrostatic self-assembly[J]. Construction and Building Materials,2020,256:119452. doi: 10.1016/j.conbuildmat.2020.119452 [20] 张立卿. 水泥基材料纳米改性机制与复合静电自组装纳米填料改性[D]. 大连: 大连理工大学, 2018.ZHANG Liqing. Nano-modification mechanisms and electrostatic self-assembly nano filler modification of cement based materials[D]. Dalian: Dalian University of Technology, 2018(in Chinese). [21] ZHANG L Q, DING S Q, LI L W, et al. Effect of characteristics of assembly unit of CNT/NCB composite fillers on properties of smart cement-based materials[J]. Composites Part A: Applied Science and Manufacturing,2018,109:303-320. doi: 10.1016/j.compositesa.2018.03.020 [22] ZHANG L Q, HAN B G, OUYANG J, et al. Multifunctionality of cement based composite with electrostatic self-assembled CNT/NCB composite filler[J]. Archives of Civil and Mechanical Engineering,2017,17(2):354-364. doi: 10.1016/j.acme.2016.11.001 [23] ZHANG L Q, LI L W, WANG Y L, et al. Multifunctional cement-based materials modified with electrostatic self-assembled CNT/TiO2 composite filler[J]. Construction and Building Materials,2020,238:117787. doi: 10.1016/j.conbuildmat.2019.117787 [24] HAN B G, ZHANG L Q, SUN S W, et al. Electrostatic self-assembled carbon nanotube/nano carbon black composite fillers reinforced cement-based materials with multifunctionality[J]. Composites Part A: Applied Science and Manufacturing,2015,79:103-115. doi: 10.1016/j.compositesa.2015.09.016 [25] HAN B G, SUN S W, DING S Q, et al. Review of nanocarbon-engineered multifunctional cementitious composites[J]. Composites Part A: Applied Science and Manufacturing,2015,70:69-81. doi: 10.1016/j.compositesa.2014.12.002 [26] HAN B G, WANG Y Y, DING S Q, et al. Self-sensing cementitious composites incorporated with botryoid hybrid nano-carbon materials for smart infrastructures[J]. Journal of Intelligent Material Systems and Structures,2017,28(6):699-727. doi: 10.1177/1045389X16657416 [27] 罗健林. 碳纳米管水泥基复合材料制备及功能性能研究[D]. 哈尔滨: 哈尔滨工业大学, 2009.LUO Jianlin. Fabrication and functional properties of multi-walled carbon nanotube/cement composites[D]. Harbin: Harbin Institute of Technology, 2009(in Chinese). [28] LIU L Y, XU J X, YIN T J, et al. Improved conductivity and piezoresistive properties of Ni-CNTs cement-based composites under magnetic field[J]. Cement and Concrete Composites,2021,121:104089. doi: 10.1016/j.cemconcomp.2021.104089 [29] YIN T J, XU J X, WANG Y, et al. Increasing self-sensing capability of carbon nanotubes cement-based materials by simultaneous addition of Ni nanofibers with low content[J]. Construction and Building Materials,2020,254:119306. doi: 10.1016/j.conbuildmat.2020.119306 [30] WANG L N, ASLANI F. Self-sensing performance of cementitious composites with functional fillers at macro, micro and nano scales[J]. Construction and Building Materials,2022,314:125679. doi: 10.1016/j.conbuildmat.2021.125679 [31] DONG S F, ZHANG W, WANG D N, et al. Modifying self-sensing cement-based composites through multiscale composition[J]. Measurement Science and Technology,2021,32(7):74002. doi: 10.1088/1361-6501/abdfed [32] 左俊卿, 周虹, 姚武, 等. CNT-CF水泥基材料传感特性研究[J]. 材料导报, 2017, 31(22):125-129. doi: 10.11896/j.issn.1005-023X.2017.022.025ZUO Junqing, ZHOU Hong, YAO Wu, et al. Research on the sensing properties of CNT-CF/cement-based materials[J]. Materials Reports,2017,31(22):125-129(in Chinese). doi: 10.11896/j.issn.1005-023X.2017.022.025 [33] ZHANG L Q, DING S Q, DONG S F, et al. Piezoresistivity, mechanisms and model of cement-based materials with CNT/NCB composite fillers[J]. Materials Research Express,2017,4(12):125704. doi: 10.1088/2053-1591/aa9d1d [34] LUO J L, ZHANG C W, DUAN Z D, et al. Influences of multi-walled carbon nanotube (MCNT) fraction, moisture, stress/strain level on the electrical properties of MCNT cement-based composites[J]. Sensors and Actuators A: Physical,2018,280:413-421. doi: 10.1016/j.sna.2018.08.010 [35] DING S Q, XIANG Y, NI Y Q, et al. In-situ synthesizing carbon nanotubes on cement to develop self-sensing cementitious composites for smart high-speed rail infrastructures[J]. Nano Today,2022,43:101438. doi: 10.1016/j.nantod.2022.101438 [36] JANG D, YOON H N, SEO J, et al. Effects of exposure temperature on the piezoresistive sensing performances of MWCNT-embedded cementitious sensor[J]. Journal of Building Engineering,2022,47:103816. doi: 10.1016/j.jobe.2021.103816 [37] LOUKILI A, KHELIDJ A, RICHARD P. Hydration kinetics, change of relative humidity, and autogenous shrinkage of ultra-high-strength concrete[J]. Cement and Concrete Research,1999,29(4):577-584. doi: 10.1016/S0008-8846(99)00022-8 [38] ZHANG L Q, DING S Q, HAN B G, et al. Effect of water content on the piezoresistive property of smart cement-based materials with carbon nanotube/ nanocarbon black composite filler[J]. Composites Part A: Applied Science and Manufacturing,2019,119:8-20. doi: 10.1016/j.compositesa.2019.01.010 [39] UBERTINI F, LAFLAMME S, CEYLAN H, et al. Novel nanocomposite technologies for dynamic monitoring of structures: A comparison between cement-based embeddable and soft elastomeric surface sensors[J]. Smart Materials and Structures,2014,23(4):045023. doi: 10.1088/0964-1726/23/4/045023 [40] MENG W N, KHAYAT K. Effects of saturated lightweight sand content on key characteristics of ultra-high-performance concrete[J]. Cement and Concrete Research,2017,101:46-54. doi: 10.1016/j.cemconres.2017.08.018 -
下载:
点击查看大图
计量
- 文章访问数: 614
- HTML全文浏览量: 222
- PDF下载量: 12
- 被引次数: 0
