scholarly journals Fuzzy Logic-Based and Nondestructive Concrete Strength Evaluation Using Modified Carbon Nanotubes as a Hybrid PZT–CNT Sensor

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2953
Author(s):  
Najeebullah Tareen ◽  
Junkyeong Kim ◽  
Won-Kyu Kim ◽  
Seunghee Park
Keyword(s):  
Carbon Nanotubes ◽  
Fuzzy Logic ◽  
Concrete Strength ◽  
Testing Machine ◽  
Cementitious Materials ◽  
Temperature History ◽  
Strength Development ◽  
Mixture Ratio ◽  
Electromechanical Impedance ◽  
Maturity Method

Concrete strength and factors affecting its development during early concrete curing are important research topics. Avoiding uncertain incidents during construction and in service life of structures requires an appropriate monitoring system. Therefore, numerous techniques are used to monitor the health of a structure. This paper presents a nondestructive testing technique for monitoring the strength development of concrete at early curing ages. Dispersed carbon nanotubes (CNTs) were used with cementitious materials and piezoelectric (PZT) material, a PZT ceramic, owing to their properties of intra electromechanical effects and sensitivity to measure the electromechanical impedance (EMI) signatures and relevant properties related to concrete strength, such as the elastic modulus, displacement, acceleration, strength, and loading effects. Concrete compressive strength, hydration temperature, mixture ratio, and variation in data obtained from the impedance signatures using fuzzy logic were utilized in the comparative result prediction method for concrete strength. These results were calculated using a fuzzy logic-based model considering the maturity method, universal testing machine (UTM) data, and analyzed EMI data. In the study, for data acquisition, a hybrid PZT–CNT sensor and a temperature sensor (Smart Rock) were embedded in the concrete to obtain the hydration temperature history to utilize the concrete maturity method and provide data on the EMI signatures. The dynamic changes in the medium caused during the phase in the concrete strengthening process were analyzed to predict the strength development process of concrete at early curing ages. Because different parameters are considered while calculating the concrete strength, which is related to its mechanical properties, the proposed novel method considers that changes in the boundary condition occurring in the concrete paste modify the resonant frequency response of the structure. Thus, relating and analyzing this feature can help predict the concrete strength. A comprehensive comparison of the results calculated using the proposed module, maturity method, and cylindrical specimens tested using the UTM proved that it is a cost-effective and fast technique to estimate concrete strength to ensure a safe construction of reinforced cement concrete infrastructures.

Prediction of the Strength Development of Fly Ash Concrete

2010 ◽  
Vol 150-151 ◽  
pp. 1026-1033 ◽  
Author(s):  
Ming Hui Liu ◽  
Yuan Feng Wang
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Concrete Strength ◽  
Strength Development ◽  
Standard Temperature ◽  
Development Models ◽  
Fly Ash Concrete ◽  
Strength Tests ◽  
Maturity Method ◽  
Predicted Model

The effect of fly ash in improving the mechanical properties of concrete is investigated and the existing concrete strength development models are studied. Based on the chemic reactivity properties between fly ash and cement, an appropriate concrete strength model are chosen, and a new model for the fly ash strength factor combing Maturity method is built up and the factors are regressed by existing experimental datum. A total of 24 concretes, including two concretes were produced with two partial fly ash replacement ratios (23.7%, 32.7%). The cubic samples produced from ash fly concrete were demoulded after a day, and cured at standard temperature ( in GB/T 50081-2002) with 100% relative humidity until 28 days, then cured in water. The compressive strength tests were carried out on the cubic specimens at different ages. The compressive strength with time was evaluated by using the new predicted model. It was found that the calculated results by new method are fit the experimental data well.

Maturity of Prestressed Self-Consolidating Concrete

2013 ◽  
Vol 368-370 ◽  
pp. 945-948
Author(s):  
Wu Jian Long ◽  
Wei Lun Wang ◽  
Feng Xing ◽  
Man Tang Li
Keyword(s):  
Concrete Strength ◽  
Maximum Size ◽  
Fundamental Concept ◽  
Strength Level ◽  
Strength Development ◽  
Mixture Proportioning ◽  
Self Consolidating Concrete ◽  
Maturity Method

The maturity method applies the fundamental concept that concrete strength develops with time as the cement hydrates and releases heat. The rate of strength development at early ages is related to the rate of hydration of cement. In this investigation, 27 Self-consolidating concrete (SCC) mixtures made with various mixture proportioning parameters, including maximum size and type of aggregate, type and content of binder, and w/cm were evaluated. Based on this investigation, SCC proportioned with 0.33 w/cm exhibited lower maturity at the same strength level compared to that with 0.38 w/cm; and for the same 0.38 w/cm, SCC made with Type MS cement had higher maturity compared to those proportioned with Type HE + 20%FA and Type HE + 30%S, at the same strength level.

Strength development monitoring and dynamic modulus assessment of cementitious materials using EMI-Miniature Prism based technique

2019 ◽  
Vol 19 (2) ◽  
pp. 373-389 ◽  
Author(s):  
Xubin Lu ◽  
Yee Yan Lim ◽  
Iman Izadgoshasb ◽  
Chee Kiong Soh
Keyword(s):  
Lead Zirconate Titanate ◽  
Dynamic Modulus ◽  
Model Updating ◽  
Cementitious Materials ◽  
Cementitious Material ◽  
Experimental Results ◽  
Strength Development ◽  
Fe Model ◽  
Curing Process ◽  
Electromechanical Impedance

Electromechanical impedance (EMI) technique provides an alternative means of characterizing strength development of early age concrete on a real-time basis. However, most existing studies employing the technique heavily rely on statistical tools for strength development characterization. This article proposes a new impedance-based approach to strength and dynamic modulus assessment of cementitious materials. In this approach, a lead zirconate titanate patch is surfaced-bonded on a customized cementitious material specimen, known as ‘Miniature Prism’, in which the conductance signatures throughout the curing process are acquired. A 3D coupled field finite element (FE) model is then developed to compute the conductance signatures and model updating is performed using the experimental results. The conductance signatures computed by the updated FE model are found to be in good agreement with experimental results. The key contribution of this approach is the use of ‘Miniature Prism’ which ensures consistency of the resonance peaks in the conductance spectrum between identical specimens. This has been very difficult, if not impossible, to achieve with the conventional EMI technique. This merit allows for modelling of the electromechanical system and hence parametrically predicting the dynamic modulus of elasticity of the cementitious material throughout the curing process. Comparative study is also conducted on various conventional and advanced techniques and results indicate that the proposed technique is effective in strength assessment of cementitious materials. In addition, the technique is suitable for autonomous online monitoring purpose, and thus exhibits promising potential to substitute the conventional non-destructive testing methods.

scholarly journals Assessment of Strength Development at Hardened Stage on High-Strength Concrete Using NDT

2020 ◽  
Vol 10 (18) ◽  
pp. 6261
Author(s):  
Taegyu Lee ◽  
Jaehyun Lee ◽  
Hyeonggil Choi
Keyword(s):  
Compressive Strength ◽  
High Strength Concrete ◽  
Concrete Strength ◽  
High Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Temperature History ◽  
Strength Development ◽  
Strength Concrete

This study proposes model formulae for predicting the strength of concrete by analyzing the relationships between the results of nondestructive testing (NDT) methods and the compressive strength of concrete specimens at the hardened stage. Further, NDT of concrete molds and mock-up specimens was conducted using NDT methods (rebound hammer, ultrasonic pulse velocity). The water/cement (W/C) ratios were set to 0.48, 0.41, and 0.33 to achieve concrete strengths within the compressive strength range of 24–60 MPa. The evaluation parameters included the fresh concrete properties, compressive strength (mold and core), temperature history, maturity, rebound value, and ultrasonic pulse velocity. Evaluation results indicated that the reliability of existing models, based on the rebound and ultrasonic pulse velocity, is significantly low on high-strength concrete of 40 MPa or higher, and cannot satisfy the ±20% error range. Consequently, this study proposes a regression equation of the concrete strength based on the experimental rebound and ultrasonic pulse velocity values in a 24–60 MPa range, which offers satisfactory reliability.

scholarly journals Nondestructive Wireless Monitoring of Early-Age Concrete Strength Gain Using an Innovative Electromechanical Impedance Sensing System

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
C. P. Providakis ◽  
E. V. Liarakos ◽  
E. Kampianakis
Keyword(s):  
Concrete Strength ◽  
Strength Development ◽  
Early Age ◽  
Strength Gain ◽  
Impedance Sensing ◽  
Electromechanical Impedance ◽  
Sensing System ◽  
Cracking Control ◽  
Wireless Usb ◽  
Early Age Concrete

Monitoring the concrete early-age strength gain at any arbitrary time from a few minutes to a few hours after mixing is crucial for operations such as removal of frameworks, prestress, or cracking control. This paper presents the development and evaluation of a potential active wireless USB sensing tool that consists of a miniaturized electromechanical impedance measuring chip and a reusable piezoelectric transducer appropriately installed in a Teflon-based enclosure to monitor the concrete strength development at early ages and initial hydration states. In this study, the changes of the measured electromechanical impedance signatures as obtained by using the proposed sensing system during the whole early-age concrete hydration process are experimentally investigated. It is found that the proposed electromechanical impedance (EMI) sensing system associated with a properly defined statistical index which evaluates the rate of concrete strength development is very sensitive to the strength gain of concrete structures from their earliest stages.

Effect of ground granulated blast funrnace slag and fly ash on strength, permeability, and under-water abrasion of fine-grained concrete

2020 ◽  
Vol 71 (7) ◽  
pp. 775-788
Author(s):  
Quyet Truong Van ◽  
Sang Nguyen Thanh
Keyword(s):  
Fly Ash ◽  
Concrete Strength ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Chloride Permeability ◽  
Cement Replacement ◽  
Fine Grained ◽  
Granulated Blast Furnace Slag ◽  
Compressive Strength Test ◽  
Economic Ground

The utilisation of supplementary cementitious materials (SCMs) is widespread in the concrete industry because of the performance benefits and economic. Ground granulated blast furnace slag (GGBFS) and fly ash (FA) have been used as the SCMs in concrete for reducing the weight of cement and improving durability properties. In this study, GGBFS at different cement replacement ratios of 0%, 20%, 40% and 60% by weight were used in fine-grained concrete. The ternary binders containing GGBFS and FA at cement replacement ratio of 60% by weight have also evaluated. Flexural and compressive strength test, rapid chloride permeability test and under-water abrasion test were performed. Experimental results show that the increase in concrete strength with GGBFS contents from 20% to 40% but at a higher period of maturity (56 days and more). The chloride permeability the under-water abrasion reduced with the increasing cement replacement by GGBFS or a combination of GGBFS and FA

scholarly journals Compressive Strength Gain Behavior and Prediction of Cement-Stabilized Macadam at Low Temperature Curing

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Yongli Xu ◽  
Guang Yang ◽  
Hongyuan Zhao
Keyword(s):  
Compressive Strength ◽  
Low Temperature ◽  
Curing Temperature ◽  
Strength Development ◽  
Construction Process ◽  
Strength Gain ◽  
Estimation Model ◽  
Maturity Method ◽  
Temperature Ranges ◽  
Natural Temperature

For cement-based materials, the curing temperature determines the strength gain rate and the value of compressive strength. In this paper, the 5% cement-stabilized macadam mixture is used. Three indoor controlled temperature curing and one outdoor natural curing scenarios are designed and implemented to study the strength development scenario law of compressive strength, and they are standard temperature curing (20°C), constant low temperature curing (10°C), day interaction temperature curing (varying from 6°C to 16°C), and one outdoor natural temperature curing (in which the air temperature ranges from 4°C to 20°C). Finally, based on the maturity method, the maturity-strength estimation model is obtained by using and analyzing the data collected from the indoor tests. The model is proved with high accuracy based on the validated results obtained from the data of outdoor tests. This research provides technical support for the construction of cement-stabilized macadam in regions with low temperature, which is beneficial in the construction process and quality control.

scholarly journals Effects of carbon nanotubes on expanded glass and silica aerogel based lightweight concrete

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Suman Kumar Adhikary ◽  
Žymantas Rudžionis ◽  
Simona Tučkutė ◽  
Deepankar Kumar Ashish
Keyword(s):  
Carbon Nanotubes ◽  
Compressive Strength ◽  
Silica Aerogel ◽  
Lightweight Concrete ◽  
Lightweight Aggregate ◽  
Cementitious Materials ◽  
Lightweight Aggregate Concrete ◽  
Multi Wall Carbon Nanotubes ◽  
Sem Image ◽  
Study Results

AbstractThis study is aimed to investigate the effect of carbon nanotubes on the properties of lightweight aggregate concrete containing expanded glass and silica aerogel. Combinations of expanded glass (55%) and hydrophobic silica aerogel particles (45%) were used as lightweight aggregates. Carbon nanotubes were sonicated in the water with polycarboxylate superplasticizer by ultrasonication energy for 3 min. Study results show that incorporating multi-wall carbon nanotubes significantly influences the compressive strength and microstructural performance of aerogel based lightweight concrete. The addition of carbon nanotubes gained almost 41% improvement in compressive strength. SEM image of lightweight concrete shows a homogeneous dispersal of carbon nanotubes within the concrete structure. SEM image of the composite shows presence of C–S–H gel surrounding the carbon nanotubes, which confirms the cites of nanotubes for the higher growth of C–S–H gel. Besides, agglomeration of carbon nanotubes and the presence of ettringites was observed in the transition zone between the silica aerogel and cementitious materials. Additionally, flowability, water absorption, microscopy, X-ray powder diffraction, and semi-adiabatic calorimetry results were analyzed in this study.

scholarly journals Use of Treated Non-Ferrous Metallurgical Slags as Supplementary Cementitious Materials in Cementitious Mixtures

2021 ◽  
Vol 11 (9) ◽  
pp. 4028
Author(s):  
Asghar Gholizadeh Vayghan ◽  
Liesbeth Horckmans ◽  
Ruben Snellings ◽  
Arne Peys ◽  
Priscilla Teck ◽  
...  
Keyword(s):  
Mechanical Performance ◽  
Cementitious Materials ◽  
Supplementary Cementitious Materials ◽  
Partial Replacement ◽  
Strength Development ◽  
Supplementary Cementitious Material ◽  
Performance Requirements ◽  
Metallurgical Slags ◽  
Leaching Behaviour ◽  
Kinetics Of

This research investigated the possibility of using metallurgical slags from the copper and lead industries as partial replacement for cement. The studied slags were fayalitic, having a mainly ferro-silicate composition with minor contents of Al2O3 and CaO. The slags were treated at 1200–1300 °C (to reduce the heavy metal content) and then granulated in water to promote the formation of reactive phases. A full hydration study was carried out to assess the kinetics of reactions, the phases formed during hydration, the reactivity of the slags and their strength activity as supplementary cementitious material (SCM). The batch-leaching behaviour of cementitious mixtures incorporating treated slags was also investigated. The results showed that all three slags have satisfactory leaching behaviour and similar performance in terms of reactivity and contribution to the strength development. All slags were found to have mediocre reactivity and contribution to strength, especially at early ages. Nonetheless, they passed the minimum mechanical performance requirements and were found to qualify for use in cement.

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