# Investigation of Insulation Properties Using Microwave Nondevastating Methodology to Predict the Strength of Polymer Materials

Authors: Anitha Gopalan; S Ramesh; Nirmala P; Govindaraj Ramkumar; Satyajeet Sahoo; S. Agnes Shifani; S. Arockia Jayadhas
Journal: Advances in Materials Science and Engineering
 (2022)

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## Abstract

The study was extended and developed to predict the roughness of polymer-based materials using the latest data mining techniques. Different types of particles are used in polymer-based materials, which characterize the roughness of polymer-based materials. The research study focused on predicting the roughness of bulk polymer materials using fly ash. Fly ash is an alternative material that is used to replace both cement and fine aggregate to some extent. Particles such as silica fume, limestone, and slag have been used in place of concrete, but flash has received more attention than other elements. It is important to express the insulation properties of polymer materials using the microwave nondevastative method. Finally, this article concludes by predicting the strength of polymer materials by measuring insulation properties using the microwave nondevastative method.


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## Body

## 1. Introduction

The basic mixture of accumulation and lake is defined as concrete. Water and the binding material mix to form polymer concrete granules and these particles recombine with the accumulating material to form a rock structure. Due to the chemical reaction of water and the bonding material, the stone becomes a little harder and stronger. The roughness of polymer concrete increases with the age of the polymer concrete and the amount of mixing and curing affects the roughness in compression [1]. This also includes mixing, treating, inserting, and inspecting the concrete. Most of the construction process uses high roughness concrete. Polymer concrete has a superior blend of presentation and consistency requirements known as high roughness concrete. Typically, polymer concrete is said to have a strong point when it is set for 28 days. Therefore, different countries have different mixing ratios and terminologies to define polymer concrete as high roughness concrete [2].There are 24 types of polymer concrete used for construction purposes, and in this case, the most commonly used polymer concrete will be discussed. These are bearing concrete, normal strength concrete, ultrahigh performance polymer concrete, and polymer concrete. In this polymer, the concrete plays an important role, the aggregates bond with the polymer rather than with the cement, helping to reduce the void volume in the aggregate. Polymer concrete is divided into three types: impregnated concrete, partially impregnated polymer concrete, and polymer cement concrete [3].Cement is the most expensive ingredient in polymer concrete mixes. When the cost of cement increases, the cost of polymer concrete also increases; the only way to reduce the cost of polymer concrete is to reduce the cost of cement or substitute another material instead of cement particles. Most research studies have been done to reduce or replace cement particles. Materials such as slag, silica fume, and limestone are some of the powdered materials that replace cement particles. The main purpose of cement in polymer concrete is to fix each fine or coarse aggregate and the cement paste is filled between the aggregate particles [4]. The former depends on the specific surface of the accumulator and the aggregate depends on the porosity of the accumulator. In some cases, polymer concrete is recycled and used again, but this reduces the roughness of the concrete.Polymer concrete materials contain defects, cracks, defects, and inhomogeneities and to find these defect patterns in polymer concrete materials, different types of techniques have been used. This technique is classified into two types: devastating methods and nondevastating methods. The devastating type evaluation technique has many advantages over the nondevastating type evaluation method [5]. The main advantage of the devastating method is that it is less expensive and has good drilling conditions compared to nonmetallic materials, but the major disadvantage of devastating methods is that they cannot come into contact with the microwave sensor. This is remedied by the method of the nondevastating type. This method is accompanied by the insulating properties of metals and polymer concrete [6, 7].The paper explores predicting the roughness of a polymer concrete material with the replacement of fly ash in the place of cement using a neural network. This also defines the insulation properties of concrete. The introduction part defines the overall basic nature of polymer concrete and the predicted rate. Section2 rolls around the related work done based on the prediction level and the effect of ration in a polymer concrete material. The scope of the work is determined in Section 3 and the experimental work is defined in Section 4 and then it is concluded in the last section.


## 2. Related Works

To predict the compressive roughness of the polymer concrete of slump, the authors of [6] proposed a method using a neural network. This method defines the roughness of the concrete, mostly the research study deals with higher roughness. Although a fly ash content lower than 25% of the total cement content is a regular, when it is used in concrete, high volume fly ash polymer concrete (HVFA) is not widely used due to the perceived low forces in young children. Corresponding bottles were used during this process to estimate the roughness of HVFA polymer concrete in place at an early age and to confirm the expected mature forces. The results showed that the roughness of the standard and field hardened cylinders underestimates the roughness of the existing concrete. The high temperature defines the mass characteristics of the structural element. This increases the reasonable place of the construction, roughness, and match cured cylinders.Previously issued tentative data on the impact of nuclear radioactive on the assets of ordinary polymer concrete are canalized and 2 are evaluated. Neutron radioactive with a crore fence greater than 1 × 1 o19 n/cm may have an adverse effect on the roughness of the polymer concrete and the elasticity of ball joints [8]. The thermal expansion coefficient, thermal conductivity, and shielding assets of polymer concrete are largely unaffected by radioactivity. Radioactive damage is mainly caused by mesh defects in the cumulative, resulting in increased cumulative and polymer concrete volume. Various cumulative factors present a different radioactive resistance, so the selection of appropriate cumulative is the important parameter of frost in the design of a radioactive-resistant concrete.The compressive roughness of polymer concrete is the most commonly used criterion for polymer concrete production. However, compression testing of the roughness of polymer concrete samples is a complex and time-consuming task [9]. Therefore, forecasting resistance prior to polymer concrete installation is highly necessary. This study presents the application effort of the neural network technique to predict the compression resistance of polymer concrete as a function of the proportions of the polymer concrete mixture. The data set of a combination of different industries was needed for the training and testing data and they also require trial and error for forecasting the compressive roughness [10].


### 2.1. Scope of Research

The research study is based on the prediction of the strength of polymer concrete using the neural network and then on the study of insulation properties of polymer concrete using the nondevastating microwave method.


## 2.1. Scope of Research

The research study is based on the prediction of the strength of polymer concrete using the neural network and then on the study of insulation properties of polymer concrete using the nondevastating microwave method.


## 3. Materials and Methods

The analysis was done on polymer concrete with coal fly ash and glass fibers. The following raw materials were used to prepare the concrete: cement, fly ash, river aggregate, gravel, and glass fibers. A very small round particle is combined together and they are known as the coal ash, and they also contain amorphous glass and crystalline phases. The diameter of the concrete is said to be 0.01 to 400µm. The main property of coal is the grey color powder substance and the presence of pozzolanic assets. The pozzolanic assets are said to have high binding capacity and this is mostly used in the preparation of concrete and concrete mixed products. Table 1 defines the features of the coal ash used for the experimental analysis. The management concrete composition was grade C25/30: cement 360 kg/m3 (of that 100 percent was replaced with coal fly ash), diameter 0–4 metric linear unit in an exceedingly amount of 803.16 kg/m3, diameter 4–8 metric linear unit in an exceedingly amount of 384.12 kg/m3, diameter 8–16 metric linear unit in an exceedingly amount of 558.72 kg/m3, water one hundred eighty L/m3, and superplasticizer kind Cervus sika ViscoCrete-1040 in an exceedingly indefinite quantity of one. 4% of the cement weight. Close to the management combination, a variety of thirteen mixes were established by employing a turned focused composed program of second order, with 2 variables. The overall range of tests was statistically established taking into consideration the number of freelance variables, the sort of analysis that was done and therefore the style of experimental setup that was chosen. The following 2 variables were chosen for the input: length and indefinite quantity of optical fiber. The dosages of glass fibers were between zero, 25%, and 1.75% of the concrete mass; therefore, the lengths were between five metric linear units and thirty five metric linear units. The experimental matrix contains a variety of thirteen experiments (13 mixes).Table 1
Features of coal ash.
ElementCoal ash (Wt %)At %CL17.1826.90NL01.3501.81OL37.5544.15NaL00.7000.57MgL0.5500.42AlL13.1009.15SiL18.4012.35SL00.7200.42LL01.750.85CaL03.1801.50TiL01.7200.69FeL04.0101.36MatrixAlterationZAFThe table represents the mass percentage (Wt) and atomic number (At) and L represents the layer to which the chemical properties are determined. In different amounts, the glass fiber is added to mix the concrete. The percentage of the fiber was between 0.25% and 1.75% weight of concrete and the length of the fiber was between 5 mm and 35 mm. The yarn strength is determined as the properties of the fiber and it is about 76.6 N and the loop strength is about 101.86 N [10]. The aggregate was different types of natural sand and river gravel, and the diameter is of 4–8 mm and 8–16 mm. By different parameters like aggregate, water, cement, and other materials, the mechanical assets of the concrete were affected. Hence, by influencing the coal ash and the fiberglass, the workable strength of the concrete can be evaluated [11].In Figure1, factors affecting concrete properties are illustrated. The mechanical properties of concrete are mainly influenced by this type of factor. By mixing the aggregate with cement, coal ash, and water, the concrete is prepared, and the glass fiber was introduced into the fresh mixed particle before the final process. Then, the concrete is transformed into the mold and kept at a condition of 20°C. This is a normal temperature to be kept in. As polymer concrete use a polymer binder instead of cement and other aggregate particles, they are totally different from the conventional type of concrete. Although it may be used in construction such as conventional polymer concrete [12], it has several unique features that make it more durable than conventional concrete. Polymeric concrete has the following properties:Curing property:The hardening effect is quick at ambient temperatures between −18 and 40°C (0 to 104°F). Polymer concrete develops 70% resistance after a day of hardening at room temperature while conventional polymer concrete gains only 20% of its 28-day resistance in a day.Strength:Polymer concrete has high tensile strength, bending strength, compression strength, and good abrasion resistance compared to cemented concrete.Durability:Polymer concrete provides good long-term durability of concrete with regard to freezing and thawing cycles and chemical attacks, as it reduces chloride and salt intrusion.Lightweight:When polymers are used in concrete, light polymer concrete is produced.Figure 1
Factors affecting concrete properties.


### 3.1. Bond-Slip Characteristics of Polymer-Concrete

The load end and the slip end are essentially the same, but they are somewhat delayed in moving the free end [13]. Hence, the complete improvement is often merely segmented into 3 stages [14].Tables2 and 3 define the relationship between the moisture strength and bonding strength. When the concrete is totally saturated, increasing the chemical compound density has very little result on the bond strength.Table 2
Moisture strength.
NumberTemperature (°C)Moisture (%)Average moisture (%)1–30000000.990.913–1501.040.831.120.9625–2700.481.31.090.9537–391.201.80Table 3
Bonding strength.
NoTemperature (°C)Bond strength (MPa)Avg. bond strength (MPa)1–300.430.490.5700.480.50.3913–1500.450.720.100.3025–2700.650.201.130.2837–390.20.11


### 3.2. Neural Network Model Design Process

For predicting the strength of the concrete, the error propagation and the recall algorithm is used because this method can proficiently solve the variable problems in the system. The step-by-step process for the expansion of ANN has been designed. To predict the strength of the polymer concrete material, single ANN architecture is used. Based on the research design, cement is replaced by fly ash and the mixture is made of fine aggregate and coarse aggregate. By using the neural network method, the strength of the polymer concrete is predicted and the microwave nondevastating method is used to define the insulation properties of the concrete [15]. To blend the polymer concrete, the ribbon mixture is made and then they are mixed together to form concrete. Specific representation is made for the polymer concrete mix such as specific gravity and fineness modulus of sand and coarse are 2.64, 2.2, and 2.81, 6.5, respectively.The neural network developed in this research comprises seven variable quantities in the input layer and two variables in the output layer and is represented in Figure2 [16]. The main problem is choosing the hidden layer to any extent and this depends on the number and training design quality; this helps to analyze the optimal sum of the hidden layers. The rate of components used in this study is given below:No of input element = 7No of hidden layer = 2No of first hidden layer = 5No of second hidden layer = 3No of output layer = 2Figure 2
Neural network model.Based on the binding, the mixture has to be blend for 2 minutes to get a perfect mixture. To make the polymer concrete, a cube sample is taken and it is casted using the steel molds, and to replace the fly ash in the place of cement or sand, a table vibrator is used. The following equation is used to predict the strength of the polymer concrete material [17]. Five features were involved in the modeling process of the neural networks; they are data acquisition, architecture, learning process, and testing. During the testing process, certain errors could occur and they are expressed in terms of root mean square and the expression is as follows:(1)RMS=1d∗∑ivi−pi.Despite the variance and the mean absolute percentage error, the sum of the square error are analyzed using the following expression:(2)R2=1−∑ivi−pi∑ipi2,MeanAbsolutePercentageError=p−vp∗100,SumofSquareError=∑ivi−pi2.In which,v denotes the value of the target, p denotes the value of output, and d is the pattern design. From the outside environment, the information is received by the input layer neurons and the information transmitted is passed to the hidden layer. Passing the information to the hidden layer does not require any performance calculation [18]. The incoming information in the hidden layer is performed and the useful information is extracted to recreate the mapping process from the input space. The input layer is interrelated by the weight. The network prediction is produced to the outside world by the output neurons. For choosing the neurons in the hidden layer, there is no general rule or process that has to be done. The quality of the training pattern is influenced by the choice of the hidden layer [19].


### 3.3. Technique of Radio Wave Nondevastating Monitoring

To detect the 1–100 kHz radio frequency range, nondevastating radio wave monitoring is used. The radio wave frequency is categorized into two different methods; they are the parallel plate electrode system and mobile insulation robe sensor. The first method is widely used in the medical laboratory and research units and the second method is used in designing the surface sensor and this sensor is lightweight and simple [20]. This method is widely used in the surface senor because this could provide data at different points. In this research study, the nonconductor properties of polymer concrete material are determined via the microwave non-devastating method which is a part of the MDPS technique.The microwave nondevastating testing is an important method related to the electrical method in which the utilization of microwave frequency is done. The alternating current or the electromagnetic wave with the frequencies range of 300 MHz and 300 GHz is termed as microwave. The microwave nondevastating system uses the frequency range of about 7–15 GHz. The good conducting material contains a short penetrating range than other conducting materials and the microwave nondevastating method is widely used in nonmetallic materials [21]. There are two types of microwave non-devastating methods: free space microwave method and waveguide technique. The far-field region operation is carried out in the free space microwave method and the near-filed region operation is carried out in the waveguide technique [22]. The waveguide technique involves flexible coaxial lines, quadrilateral waveguide, microstrip lines, and crack cavity resonator as probes. This method uses horn antenna as it is a contactless system and Figure 3 shows the representation of free space microwave test method. The system uses the MNDT for the estimation of polymer concrete materials.Figure 3
Free space microwave method.Using two horn antennas, the free space microwave test method is done, and for blistering and getting rays, an open-ended rectangular waveguide is used. From the sample, the distance of the horn is calculated and it is done by using the frequency range. In the center of the coils, a sample holder holds the test material. It is important to align the position of the sample holder and the antenna position. In all directions, the two antennas are symmetric to each other and this is done to eradicate the dissimilarities of the incident and reflected waves. The horn antenna used here could focus on the spot of each polymer concrete material. A flat-convex lens mounted back-to-back in a conical antenna in this one convex lens provides the electromagnetic plane wave and the next one shows the focus of electromagnetic radiation. Nearly, 8–12.50 GHz frequency range is observed and it is said that the same technique can be used to predict the frequency of about 7.5 to 40 GHz.


## 3.1. Bond-Slip Characteristics of Polymer-Concrete

The load end and the slip end are essentially the same, but they are somewhat delayed in moving the free end [13]. Hence, the complete improvement is often merely segmented into 3 stages [14].Tables2 and 3 define the relationship between the moisture strength and bonding strength. When the concrete is totally saturated, increasing the chemical compound density has very little result on the bond strength.Table 2
Moisture strength.
NumberTemperature (°C)Moisture (%)Average moisture (%)1–30000000.990.913–1501.040.831.120.9625–2700.481.31.090.9537–391.201.80Table 3
Bonding strength.
NoTemperature (°C)Bond strength (MPa)Avg. bond strength (MPa)1–300.430.490.5700.480.50.3913–1500.450.720.100.3025–2700.650.201.130.2837–390.20.11


## 3.2. Neural Network Model Design Process

For predicting the strength of the concrete, the error propagation and the recall algorithm is used because this method can proficiently solve the variable problems in the system. The step-by-step process for the expansion of ANN has been designed. To predict the strength of the polymer concrete material, single ANN architecture is used. Based on the research design, cement is replaced by fly ash and the mixture is made of fine aggregate and coarse aggregate. By using the neural network method, the strength of the polymer concrete is predicted and the microwave nondevastating method is used to define the insulation properties of the concrete [15]. To blend the polymer concrete, the ribbon mixture is made and then they are mixed together to form concrete. Specific representation is made for the polymer concrete mix such as specific gravity and fineness modulus of sand and coarse are 2.64, 2.2, and 2.81, 6.5, respectively.The neural network developed in this research comprises seven variable quantities in the input layer and two variables in the output layer and is represented in Figure2 [16]. The main problem is choosing the hidden layer to any extent and this depends on the number and training design quality; this helps to analyze the optimal sum of the hidden layers. The rate of components used in this study is given below:No of input element = 7No of hidden layer = 2No of first hidden layer = 5No of second hidden layer = 3No of output layer = 2Figure 2
Neural network model.Based on the binding, the mixture has to be blend for 2 minutes to get a perfect mixture. To make the polymer concrete, a cube sample is taken and it is casted using the steel molds, and to replace the fly ash in the place of cement or sand, a table vibrator is used. The following equation is used to predict the strength of the polymer concrete material [17]. Five features were involved in the modeling process of the neural networks; they are data acquisition, architecture, learning process, and testing. During the testing process, certain errors could occur and they are expressed in terms of root mean square and the expression is as follows:(1)RMS=1d∗∑ivi−pi.Despite the variance and the mean absolute percentage error, the sum of the square error are analyzed using the following expression:(2)R2=1−∑ivi−pi∑ipi2,MeanAbsolutePercentageError=p−vp∗100,SumofSquareError=∑ivi−pi2.In which,v denotes the value of the target, p denotes the value of output, and d is the pattern design. From the outside environment, the information is received by the input layer neurons and the information transmitted is passed to the hidden layer. Passing the information to the hidden layer does not require any performance calculation [18]. The incoming information in the hidden layer is performed and the useful information is extracted to recreate the mapping process from the input space. The input layer is interrelated by the weight. The network prediction is produced to the outside world by the output neurons. For choosing the neurons in the hidden layer, there is no general rule or process that has to be done. The quality of the training pattern is influenced by the choice of the hidden layer [19].


## 3.3. Technique of Radio Wave Nondevastating Monitoring

To detect the 1–100 kHz radio frequency range, nondevastating radio wave monitoring is used. The radio wave frequency is categorized into two different methods; they are the parallel plate electrode system and mobile insulation robe sensor. The first method is widely used in the medical laboratory and research units and the second method is used in designing the surface sensor and this sensor is lightweight and simple [20]. This method is widely used in the surface senor because this could provide data at different points. In this research study, the nonconductor properties of polymer concrete material are determined via the microwave non-devastating method which is a part of the MDPS technique.The microwave nondevastating testing is an important method related to the electrical method in which the utilization of microwave frequency is done. The alternating current or the electromagnetic wave with the frequencies range of 300 MHz and 300 GHz is termed as microwave. The microwave nondevastating system uses the frequency range of about 7–15 GHz. The good conducting material contains a short penetrating range than other conducting materials and the microwave nondevastating method is widely used in nonmetallic materials [21]. There are two types of microwave non-devastating methods: free space microwave method and waveguide technique. The far-field region operation is carried out in the free space microwave method and the near-filed region operation is carried out in the waveguide technique [22]. The waveguide technique involves flexible coaxial lines, quadrilateral waveguide, microstrip lines, and crack cavity resonator as probes. This method uses horn antenna as it is a contactless system and Figure 3 shows the representation of free space microwave test method. The system uses the MNDT for the estimation of polymer concrete materials.Figure 3
Free space microwave method.Using two horn antennas, the free space microwave test method is done, and for blistering and getting rays, an open-ended rectangular waveguide is used. From the sample, the distance of the horn is calculated and it is done by using the frequency range. In the center of the coils, a sample holder holds the test material. It is important to align the position of the sample holder and the antenna position. In all directions, the two antennas are symmetric to each other and this is done to eradicate the dissimilarities of the incident and reflected waves. The horn antenna used here could focus on the spot of each polymer concrete material. A flat-convex lens mounted back-to-back in a conical antenna in this one convex lens provides the electromagnetic plane wave and the next one shows the focus of electromagnetic radiation. Nearly, 8–12.50 GHz frequency range is observed and it is said that the same technique can be used to predict the frequency of about 7.5 to 40 GHz.


## 4. Result and Discussion

The water ingestion of concrete-based materials connects with their own permeability and it is higher once the permeability is bigger. Correlation of water retention rate and its effects of standard administration test on mortars/cements solidified with three-layer nongovernmental association [23].For unlocked mortars, water retention greatness connection at 1.5 h decreases by or so four-hundredth, while that of fixed may downsize by around 50–60% contrasted and the administration test. Also, from the trial data of 50°C and 20°C, as shown in Figures4 and 5 clearly increasing the regular interaction temperature could not uniquely work on the smallness of mortars.Figure 4
Time vs. water absorption of trail data with 50°C.Figure6 shows the moisture growth content in the concrete. The cracks in the concrete are fully saturated for a prolonged immersion of time. In this research method, the sample used having high strength and the measure in the moisture content is shown in Figure 4. This shows that as the time increases, the moisture content in the concrete starts to grow, while soaking in the water the moisture rises to the peak in the initial stage and then slows down after 24 hours. Consequently, the moisture content corresponding to the 24-hour immersion period can be considered as the saturated moisture content (approximately 2.66%)Figure 5
Time vs. water absorption of trail data with 50°C.Figure 6
Moisture growth.Figure7 illustrates the relationship between bond strength and density. The research study analyzes the strength of the polymer and the concrete under 25°C and in dry conditions. Table 4 defines the relationship between the bond strength and density.Figure 7
Relationship between bond strength and density.Table 4
Relationship between the bond strength and density.
Densityρ/(g/cm³)0.10.20.40.60.81.2Bond strength (MPa)0.30.50.61.11.51.9Figures8 and 9 show the graphical representation of the comparison between the neural network and the experimental compressive strength and the slump values. The numerical value for both the compressive and slump value is calculated by the training and tests, such as root mean square and variance. Based on the proposed neural network model, the mean absolute square value is 2.61710% and 660954; in the training set, the value is 1.956210% and 5.78225% for the compressive strength of polymer concrete material. The value for variance is about 100.897% and 100.257% for the compressive polymer concrete strength and the training set is about 99.91% and 99.3455%. The variance, mean square, and square root are tested for both the compressive strength and the slump value of the polymer concrete material.Figure 8
Test sample.Figure 9
Neural vs. experimental.Figure10 shows the proposed neural network model. The comparison between the concrete strength and the slump value of HSC is plotted against the training set and test set. In each set, the slump value in the training set is high when compared to the other set and the concrete strength remain constant for both the training set and test set.Figure 10
Proposed neural network model.


## 5. Conclusion

The study describes the prediction of compressive strength of polymer-based materials and a nondestructive method is used to predict the insulating properties of polymer-based materials. The strength of polymer concrete is predicted using a neural network and by performing a predictive computation. The fly ash replacement and the preparation of polymer-based materials are explained by schematic diagrams and followed by the determination of the neural network layer for the significant strength of the polymer. The strength prediction of polymer concrete is performed and the results are tabulated based on a comparison between the neural network and the experimental setup. A training and test set was determined for the neural network system, and then, a nonharmful microwave method was performed to represent the electrical insulation and microwave frequency properties of the polymeric elementary particles. The main advantage is that by replacing cement with fly ash, the cost of the polymer can be significantly reduced. The strength frequency of polymer concrete was determined by the free-space microwave method. Overall, the study design provides a better standard for predicting the strength of polymer concrete and the insulating properties of the base polymer are studied by nondamaging microwave methods.



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*Source: 1673263-2022-08-12.xml*