The high-performance light transmitting concrete and experimental analysis of using polymethylmethacrylate optical fibers in it (original) (raw)

The high-performance light transmitting concrete and experimental analysis of using polymethylmethacrylate optical fibers in it

Danial Navabi a,∗{ }^{a, *}, Mahyar Javidruzi ∘{ }^{\circ}, Mohammad Reza Hafezi ∘{ }^{\circ}, Amir Mosavi b,c { }^{\text {b,c }}
a{ }^{a} School of Architecture and Urbanism, Shabid Beheshti University, 1983969411, Tehran, Iran
b{ }^{b} Institute of Structural Mechanics (ISM), Baohaus-Universität Weimar, 99423, Weimar, Germany
c{ }^{c} John von Neumann Faculty of Informatics, Obuda University, 1034, Budapest, Hungary

A R T I C L E I N F O

Keywords:
Light transmitting concrete
Light transmittance
Mixing design
Optical fiber
Compressive strength

A B S T R A C T

Abstract

The purpose of the current study is to investigate the optical and physical properties of high-performance light transmitting concrete which was prepared by Portland cement, polymethylmethacrylate (PMMA) optical fibers, silica fume, fine aggregate, polycarboxylate superplasticizer, silica powder, and water in a given proportion. Many samples of light transmitting concrete with 3,5,7,10,&15%3,5,7,10, \& 15 \% volumetric PMMA optical fibers in it were produced. The laboratory tests were determined in order to specify the optimum fraction of optical fibers in samples in terms of performance, and evaluation of light transmitting properties of concrete based on single highperformance concrete mixing design depending on optical fibers quantity. As the findings revealed, the compressive strength decreased with an increasing volume fraction of optical fiber in the light transmitting concrete samples. Light transmitting performance of specimens was tested by the designed lightbox and optical power method (spectrometer test). Optical power increased nonlinearly with an increasing number of optical fibers; however, it does not transmit infrared waves as well as visible waves. Considering the light transmittance of light transmitting concrete samples, compressive strength, and the amount of used optical fibers in them, the light transmitting concrete sample that contains 10%10 \% of the volumetric optical fibers in it, can be optimum in terms of cost and performance.

1. Introduction

Nowadays, for constructing intelligent buildings, it’s essential to improve an easy way to simulate or measure complex shading and daylight control system [1] and also it’s important to develop a large scale database of semi-transparent and transparent materials to guide and help the designer to choose the better solution, design, combining shape, and functionality [2].

Compared with composite materials and glass, a light transmitting concrete is a new kind of light transmitting building material that can be obtained by using large numbers of optical fibers in it [3,4]. According to the small size of fibers that transmit the light from one side to another side, the necessity of the presence of optical fibers in the concrete can be mentioned as an important factor that were attached to the concrete and form a combination of a granular material; So the result is not just a mix of glass and concrete, but also a third new material that is completely homogeneous in terms of internal structure as well as exterior surfaces [5,6][5,6]. Light transmitting concrete was invented and patented by

Hungarian architect named Aron Losonczi in 2001 and he founded his own company in 2004, named LiTraCon [7].

This type of concrete can greatly improve building energy saving, boost the lighting effect of buildings, and develop the energy efficiency of architectural lighting [8]. Light transmitting concrete is usually used as building envelopes, such as partition walls or exterior walls of the theater, museum, and offices. In Amman, light transmitting concrete was used as exterior walls of Capital Bank and also has an artistic value that can be used as decorations in bars and hotels [9,10][9,10].

As mentioned, light transmitting concrete has been used as outdoor and indoor building material in many countries, but due to the high price of optical fibers, it has limitations in marketability [11]. To overcome the drawbacks of light transmitting concrete and enhance its spread to the construction market, it is indispensable to optimize the construction of this concrete in terms of cost and performance. One way to achieve this goal is to optimize the number of optical fibers in concrete in terms of required transparency and compressive strength, which can have an important impact on the cost and performance of this

[1]

1. a{ }^{a} Corresponding author.
   E-mail address: d.navabi@mail.sbu.ac.ir (D. Navabi). ↩︎

product.
Kim et al. [11] used plastic rods instead of optical fiber to make lightweight translucent concrete. This method can reduce the cost of producing light transmitting concrete but after optical tests on samples, it was clear that the light transmittance decreases sharply with the length of the pipe. The rods flexibility was lower than PMMA (polymethylmethacrylate) optical fibers, and the compressive strength of lightweight translucent concrete accounted for about 16 MPa which is not appropriate for structural (more than 30 MPa ) application.

Pilipenko et al. [12] has tried to solve the problems above by using suitable recycled aggregates and mixing design to find a suitable solution for producing cheaper light transmitting concrete than previous products but in his study, the samples with less than 3%3 \% volumetric optical fibers in it were produced that its light transmission rate is less than 2.5%2.5 \%.

Thiago dos S. Henriques et al. [13] investigate the mechanical behavior of light transmitting concrete with ( 2,3.52,3.5, and 5%5 \% ) volumetric PMMA optical fiber in it. According to spectrometer test results, he concluded that the amount of light passing through the light transmitting concrete will increase nonlinearly by an increase in the number of optical fibers in them. He was able to make a light transmitting concrete sample with a compressive strength of more than 30 MPa , but due to the aggregates size and the short distance between the optical fibers, the mixing design stated in this study is not suitable for producing light transmitting concrete with more than 5%5 \% volumetric optical fiber in it and all the information of this research is limited to these 3 type of sample with less than 5%5 \% light transmission.

A few studies mention the number, diameter, and distance between the optical fibers in light transmitting concrete with more than 5%5 \% volumetric optical fiber in it; therefore, it is unclear whether the light transmitting concrete with more than 5%5 \% volumetric optical fibers in it can be made with their mixing design and technical data about its physical properties, because if the number of optical fibers increases and the distance between them decreases, the mortar which is made with these materials may not flow between the fibers [12].

The main goal of this paper is to study the preparation of highperformance light transmitting concrete with ( 3%,5%,7%,10%3 \%, 5 \%, 7 \%, 10 \%, &15%\& 15 \% ) volumetric optical fiber in it (more than previous samples), containing the components of raw materials, arrangement method of optical fiber, molding process and curing. Moreover, the physical, mechanical, and optical properties of samples are discussed, and the transient wavelength through this kind of concrete is analyzed. The current paper also presents the results of optical power and compressive strength of high-performance light transmitting concrete components

Table 1
Chemical Composition of Cement.

Table 2
Physical Properties of Cement.

Table 3
Physical Properties of Silica Sand.

Table 4
Physical Characteristics of the Fine Aggregate.

according to PMMA optical fibers ratio in it to find an optimum ratio of PMMA optical fibers in this type of concrete in terms of cost and performance. For producing concrete samples, Portland cement, silica fume, fine aggregate (silica sand), silica powder (instead of quartz powder), polycarboxylate superplasticizer, and water were used. Besides, the high-performance light transmitting concrete samples were made by combining innovative matrix materials, and its transmitting properties were tested by two test methods lightbox and spectrometer test, which provide the references for the preparation and design of the building materials that can be helpful for improving engineering and research application of this type of concrete.

2. Materials and methods

In order to achieve the objectives of the present study, the following tools were performed.

2.1. Raw materials

The following materials were used to produce light transmitting concrete samples:

2.1.1. Cement

Portland cement type 2 which is manufactured at Abyek Cement Company was used. Its chemical and mechanical properties are listed in

Table 5
Physical and Chemical Properties of VM-MIX201 Polycarboxylate Super Plasticizers.

Table 6
Mini Slump and Mini V-Funnel Tests Results.

Table 7
Chemical Properties of Silica Fume Produced by Iran Ferrosilice Company.

Table 8
Physical Properties of Silica Fume Produced by Iran Ferrosilice Company.

Table 1 and Table 2, respectively.

2.1.2. Aggregate

Silica sand was used in this study which its physical properties are shown in Table 3 and Table 4. The table for producing UHPC in ACI Standard 239R-18 provides the possibility of using silica powder or quartz powder (optionally) for manufacturing UHPC; hence, silica powder was used instead of quartz powder to produce the light transmitting concrete and particle size distribution of silica sand was continuous grading of 0.06−0.6 mm0.06-0.6 \mathrm{~mm}.

2.1.3. Super plasticizers

VM-MIX201 polycarboxylate superplasticizer produced by Armani

Structural Chemistry Company was used in this study that its physical and chemical properties are shown in Table 5.

The amount of plasticizing effect (in Portland Cement Type II and VM-MIX201-based paste) was measured by a mini slump and mini vfunnel tests. Tests results are shown in Table 6 which provides more information about matrix workability and the mixture proportion can be seen at Table 9.

2.1.4. Silica fume

RM 1879 Silica fume produced by Iran Ferrosilice Company was used in this study which its chemical and physical analysis specifications are shown in Table 7 and Table 8, and all results are in accordance with ASTM v1240 and ISIRI 13278 (Institute of Standards and Industrial Research of Iran).

2.1.5. Optical fiber

PMMA optical fibers with 1 mm in diameter were used to produce the light transmitting concrete (See Fig. 1). The fiber tensile strength was 45.75 MPa , the bending diameter was 9 times greater than the diameter of the optical fiber and its operating temperature was from

Fig. 1. PMMA optical fibers.

Fig. 2. Design and preparation of light transmitting concrete mold.

Fig. 3. Embedment of optical fibers and casting.

Table 9
UHPC Mixture Proportions by Mass.

−20-20 to 70∘C70^{\circ} \mathrm{C}.

2.2. Sample preparation

Light transmitting concrete samples were made by the following method.

2.2.1. Molds preparation

Since the number of optical fibers and the distance between them are important in this study(according to the direct influence on the light transmitting ratio), a method was chosen to place the fibers in the concrete with high accuracy in determining the number of fibers and their arrangement. In this method, after designing the molds in AutoCAD software, the molds were cut by laser to fit the fibers into them as its shown in Fig. 2 and then they were placed in the molds. To fit the mold walls more closely, the teeth on the molds were designed to fit precisely together to form a cubic mold and for holding the mold walls in order to prevent them from moving, triangular braces were used.

The molds were made of Plexiglas and MDF with 5 mm thick that after cutting optical fibers into equal length; they were scraped by sandpaper (due to better bonding to the concrete) and manually inserted into the mold. For fitting the optical fiber into the mold, it is better to insert the fibers into the molds before closing the mold walls, then move the mold walls and create the mold (See Fig. 3).

Because of suitable dimensions of the specimens for the compressive strength test and according to ISIRI 393 and ASTM C109, molds dimensions determined to be 5×5×5 cm5 \times 5 \times 5 \mathrm{~cm}; another reason for choosing these dimensions was to measure the transparency of samples and taking them in the lightbox.

2.2.2. Light transmitting concrete mixing design

After examining 9 different mixing designs used for producing light transmitting concrete in different studies, it was found that there is no fixed mixing design for producing light transmitting concrete with the desired density of optical fibers in it; So, according to the project requirements, studying previous mixing designs and testing several proposed mixing designs, the new mixing design was used to produce light transmitting concrete which was based on high-performance concrete mixing design. The mixing design which is shown in Table 9 is derived from the UHPC concrete mixing proportion table in ACI 239R-18.

According to Table 9 data and available materials in Iran, silica sand with the described properties in Section 2.1 was used for the mortar to
produce the light transmitting concrete thus it does not get stuck between the optical fibers and flow easily between them. If the sand size being larger than the distance between the optical fibers in light transmitting concrete, the concrete becomes porous (See Fig. 4).

As seen at Fig. 4, huge spacing inside the specimen could be achieved not only by collapsing space between fibers by aggregate agglomeration, but by low workability as well. The higher workability is, the easier the concrete pass between fibers without additional mechanical influence. Also, the quality of casting would cause a great impact on strength of concrete.

2.2.3. Curing

To open the molds, we must cut the extra optical fibers and then separate the mold walls (See Fig. 5). After removing specimens from molds, according to ISIRI 17040, they were subjected to standard curing conditions for 28 days (temperature 20±2∘C,RH95±5%20 \pm 2{ }^{\circ} \mathrm{C}, \mathrm{RH} 95 \pm 5 \% ).

Flush cutting or grinding the fiber optics allowed for a new smooth end to have a better acceptance cone of the source light. Grinding was done with a typical 3-inch angle grinder with a masonry disk and also the sandpaper was used to polish surfaces.

3. Testing methods

The following experiments were performed to measure the characteristics of light transmitting concrete to determine the optimal sample of this type of concrete due to the cost and performance.

3.1. Test methods for light transmitting properties

Two methods have been used to investigate the amount of light passing through light transmitting concrete:

In the first method, a lightbox was designed and the light source(an incandescent lamp with a filament of tungsten wire inside the bulb and a power of 120 W/110 V120 \mathrm{~W} / 110 \mathrm{~V} ) was placed on one side, light transmitting concrete in the middle (in sample window) and lux meter on the other side of it. The lux meter was located in the fixed position in the lightbox and the brightness through the sample window without and with LTC sample was measured. This would determine how much light had transmitted through the light transmitting concrete. The design and simulation of the lightbox were done in rhino’s software which is remarkable in Fig. 6. 10 samples with different percentages of optical fibers (3,5,7,10,&15)(3,5,7,10, \& 15) in them were tested by this method to determine that how much light passed through each sample.

The second experiment was conducted to determine the amount of passing light spectrums through the light transmitting concrete; this experiment was conducted in the darkroom of the light laboratory of Shahid Beheshti University, where the light transmitting concrete was placed between the light source and the spectrometer. As it shows in Fig. 7, concave and convex lenses were performed to focus light on the light transmitting concrete and spectrometer.

This experiment was done on concrete with 10%10 \% volumetric PMMA optical fiber in it and the used spectrometer was High-Resolution Spectrometer V900 which was manufactured by Fanavaran

Fig. 4. Due to coarse aggregate agglomeration of mortar, light transmitting concrete becomes porous.

Fig. 5. Cutting the extra optical fibers to open the mold.

Technologies of Light that can detect rays ranging from 200 to 1200 nm with a spectral resolution of 0.50 nm . This spectrometer works on the theory of diffraction and it’s connecting to the computer to provide the data as a graph.

3.2. Test method for investigating compressive strength

A compressive strength test was carried out to investigate the effect of using various percentages of optical fiber in light transmitting concrete on the compressive strength of this type of concrete. The method of compressive strength testing was determined according to ISIRI 393 and ASTMC109 [14]. According to these standards, light transmitting concrete cubes with 5×5×5 cm5 \times 5 \times 5 \mathrm{~cm} dimensions were made to test the compressive strength (See Fig. 8).

4. Results and discussion

4.1. Results and analysis of light transmitting properties

After making light transmitting concrete samples with different percentages of optical fiber in them, the amount of their light transmittance was measured with the lightbox test. In order to put it clearly, Table 10 manifests the number of 1 mm diameter fibers in different samples.

Moreover, Fig. 9 represents the amount of passing light from light transmitting concrete samples that contains error bars with standard errors. Simply mentioned, all these results were recorded by a lux meter
and the brightness through the sample window without and with LTC sample was measured.

These results show that the maximum light transmittance of the light transmitting concrete samples is 8.21%8.21 \% which corresponds to the sample containing 15%15 \% volumetric optical fiber and compared with observations, it seems to be low because, with the naked eye, the light transmitting through the light transmitting concrete appears to be more than this percent. For this reason, the light transmittance test with the lightbox was repeated 6 times on different days but the results of the experiment did not change. Furthermore, another reason that the light transmittance of light transmitting concrete specimens seems to be higher, can be that they transmit light as a semi-transparent object and the light is transmitted through the optical fibers thus the optical fibers act as a spotlight source and after the light has broken through optical fibers, the specimens themselves act as a semi-transparent object in which light rays divert after crossing from it in different directions and indirectly, illuminate the opposite space.

With respect to the increase in the number of optical fibers in the light transmitting concrete samples, it was expected that the amount of light passing through the samples increases linearly with increasing optical fibers [15], but the results showed that the amount of light passing through the light transmitting concrete doesn’t necessarily match the amount of light passing through them (light transmittance didn’t get double by using double optical fibers in concrete). One of the reasons for this can be in the method of making and cutting the optical fibers because the method of cutting the optical fibers also affects the amount of light they pass and it can also be said that the type of

Fig. 6. Design and simulation of the lightbox in Rhino’s software and lightbox Maquette.

Fig. 7. Experiment to investigate the passing wavelengths from light transmitting concrete.
attaching fibers with concrete influences the rate of light transmitting through them. (Increasing the level of fiber contact with concrete affects the rate of light pass through it).

According to the results obtained from the light transmittance of light transmitting concrete samples, the comparison of the slope of the increase in light passing ratio compared to the increase in the number of optical fibers in them is significant in Fig. 9. It can be concluded that the
sample containing 10%10 \% optical fiber in it is the optimum fiber content because its light transmittance is higher than the sample containing 7% optical fiber volume. Moreover, the sample contains 15%15 \% optical fiber in it and the amount of light passing through it does not differ much from the sample containing 10%10 \% fiber (their differences in light transmittance is 22%22 \% ).

In fact, the slope of the increase in light transmittance ratio is lower

Fig. 8. Compressive strength test of light transmitting concrete.

Table 10
The Volume Fraction of PMMA Optical Fibers in Light Transmitting Concrete Samples.

than in the case of 10%−15%10 \%-15 \% volumetric optical fiber in samples; to optimize cost over performance, the optical fiber content of the light transmitting concrete should not exceed 10%10 \% of the concrete volume because the main cost of producing light transmitting concrete samples is for optical fibers that is the most expensive material in the finished price and it’s the most expensive material which is needed for producing light transmitting concrete, so it is better to use this material in the best possible way to make the cost proportional to the performance of this material.

To calculate the exact economic effect of optical fibers usage in 3,5 , 7,10 , and 15%15 \% to the exact percent of money using actual costs, the
amount of optical fibers in high-performance light transmitting concrete unit (meter to a cubic meter of concrete) is shown in Table 11.

For different applications where a certain amount of light transmittance is considered in the design, the data which is shown in Fig. 9 can be used to help the light transmitting concrete to be precisely equal to the amount of light passing through that, exactly like designed sketches by an architect; For example, if a semi-transparent wall or panel is designed with 4%4 \% light transmittance, placing 10%10 \% volumetric fiber in concrete would be sufficient to make this type of material (See Fig. 10).

4.2. Results and analysis of passing light spectrums through light transmitting concrete

The transient wavelengths through the light transmitting concrete sample which is containing 10%10 \% volumetric optical fiber are shown in Fig. 11. All data were obtained by a spectrometer and converted to a graph with the computer in this case.

In this graph, the blue line represents the radiated spectrum at light transmitting concrete and the red line represents the passing spectrum through the light transmitting concrete. According to Fig. 11, it can be

Fig. 9. Light Transmittance of Light Transmitting Concrete vs. Fiber Volumetric Ratio.

Table 11
The Amount of Optical Fibers in High-Performance Light Transmitting Concrete (LTC) Unit.

seen that the wavelengths decreased after passing through light transmitting concrete, but their spectral range remained unchanged between 1 to 1100 nm . As expected, spectral displacement did not occur because optical fibers do not change the spectrum of the transmitted light; therefore, it indicates that the visible spectrum of light passes through the light transmitted concrete completely but the light intensity decrease. This means that if visible light(or colored light) radiates to the light transmitting concrete, it passes the same spectrum and can illuminate the opposite environment of the light transmitting concrete, but the transmitted light has less intensity than the intensity of radiated light (radiate spectrum).

In line with these arguments we can mention that, at wavelengths of 400−750 nm400-750 \mathrm{~nm}, the rate of attenuation of the transient wavelength is relatively constant in comparison with the radiated wavelength but at the wavelength of 750−1100 nm750-1100 \mathrm{~nm}, the intensity of the transient wavelength decreases further. In fact, the distance between the two domains in the range of 750−1100 nm750-1100 \mathrm{~nm} is greater than the distance between them in the range of 400−750 nm400-750 \mathrm{~nm}. To put it clearly, we can summarize it as d1\mathrm{d}_{1}, d2∘d3, d4\mathrm{d}_{2}{ }^{\circ} \mathrm{d}_{3}, \mathrm{~d}_{4}.

Therefore, it can be deduced from this observation that if the waves in the wavelength range of 750−1100 nm750-1100 \mathrm{~nm} radiate to the light transmitting concrete, it will pass fewer spectrums than the light waves in the 400−750 nm400-750 \mathrm{~nm} wavelength range. The wavelength range of the electromagnetic radiation, which is 380−750 nm380-750 \mathrm{~nm}, reflects visible light and our eyes are unable to see the electromagnetic radiation beyond that range [16]; this means that there are ranges of radiation wavelengths that we do not see them, such as infrared waves, therefore light transmitting concrete does not transmit infrared waves well, which means that heat does not pass through these types of fibers well, but colored light passes through it without changing color.

Due to the limited number of the tested samples, the results of the light transmitting test were compared with the results of different types of light transmitting concrete which was published in this field. It was observed that the amount of light transmission in samples with 3, and
5%5 \% volumetric optical fiber in it is slightly different (less than 0.5%0.5 \% ) from the samples which are made with the same volumetric optical fiber in it that was published in the research of Thiago dos S. Henriques et al. [12], and Yue Li et al. [13]. This small difference can also be due to the difference in the method of preparation, polishing, and testing method. The amount of light transmission through an LTC3 compared to the samples made by Pilipenko et al. [12] is different (more than 1.5%). The main reason for this difference is because of that the light transmission through the optical fiber is more than the plastic rod.

4.3. Results and analysis of compressive strength

28-day compressive strength of light transmitting concrete samples is shown in Table 12 and also Fig. 12 contains error bars with standard errors.

The results of the compressive strength test show that by increasing the volume percentage of optical fibers in the light transmitting concrete samples, their compressive strength decreases, but Fig. 12 shows that this decrease is not linear because by doubling the optical fibers in light transmitting concrete samples, its compressive strength didn’t halve either but it has been somewhat less.

By comparing the compressive strengths of LTC3 and LTC5 in Fig. 12, the number of optical fiber in the light transmitting concrete has doubled and its compressive strength decreases but not halved. Initially, light transmitting concrete samples were expected to be more compressive strength than conventional concrete, as they reinforced with optical fibers, making the light transmitting concrete more compressive resistant than conventional concrete; but the compressive strength test results show that this is not true and the conventional concrete samples have higher compressive strength than the light concrete samples. One of the reasons for the reduction in compressive strength of light transmitting concrete can be this that: despite the presence of optical fibers in concrete, in addition to the difference in modulus of elasticity of optical fibers with concrete, these fibers occupy a large volume of concrete (See Fig. 13), which is like there are pores in concrete. Many studies illustrate that porosity, pore distribution, pore diameter, pore size, and orientation of pores have significant effects on the strength of mortar and concrete [17,18]. The pore structure of hardened cement determines its permeability, compactness, porosity, and physical properties [19,20]. Consequently, optical fibers in concrete are a weakness for concrete so makes the compressive strength of light transmitting concrete less than conventional concrete; as a result, the

Fig. 10. Light transitions from light transmitting concrete samples.

Fig. 11. Rate of transmission wavelengths through light transmitting concrete.

Table 12
28-Day Compressive Strength of Light Transmitting Concrete Samples.

compressive strength of the sample without optical fibers was 82 MPa and it was more than light transmitting concrete.

Another reason it may exist is that the optical fibers are not well bonded to the light transmitting concrete and do not have the necessary adhesion to the concrete; to solve this issue and increase the adhesion of optical fibers to light transmitting concrete, the surface of the optical fibers was sanded by sandpaper and then they were placed inside the mold; hence, this method improved the adhesion to some extent.

5. Conclusion

In this study, the determination of optical fiber content in light transmitting concrete with respect to the amount of required concrete transparency was studied and the relation between the number of optical fibers in light transmitting concrete and their effect on the compressive strength of this type of concrete was determined. In order to achieve the goals of the study, the following results were obtained:
(1) By placing 3,5,7,103,5,7,10, and 15%15 \% by volume optical fiber in the light transmitting concretes, the light transmittance of the light transmitting concretes were 1.23,2.256,4.31,5.951.23,2.256,4.31,5.95, and 7.39%7.39 \%, respectively. Between the 7%7 \% and 10%10 \% levels, there was a 42%42 \% increase in fiber content and an increased light transmittance of 38%38 \% and between the 10%10 \% and 15%15 \% levels, there was a 50%50 \% increase in fiber content and an increased light transmittance of 24%24 \%. As the number of fiber increases, the amount of transmitting light from the light transmitting concrete increases nonlinearly.
(2) Considering the light transmittance of light transmitting concrete samples and the number of used optical fibers in them, the light transmitting concrete sample that contains 10%10 \% of the volumetric optical fibers in it, can be optimum in terms of cost and performance.
(3) Light transmitting concrete has high compressive strength but it’s less than the compressive strength of conventional concrete. One of the reasons for this may be that despite the fiber being in the concrete, these fibers occupy a volume of concrete which is like to exist pores in its and this is a weakness for concrete so it makes the compressive strength of the light transmitting concrete less than the compressive strength of conventional concrete. Another reason may be because the optical fibers embedded in the concrete and their attachment to the light transmitting concrete may be weak, which can be improved by increasing the contact surface of the optical fibers with light transmitting concrete.
(4) The reduction in the spectrum of passing light through the light transmitting concrete is not the same in all ranges, and this reduction in the range of 770−1100 nm770-1100 \mathrm{~nm} is more than in the range of 400−750 nm400-750 \mathrm{~nm}, which means that the light transmitting concrete does not conduct heat as well as visible light.

Moreover, evaluation of light transmitting properties of concrete based on single high-performance concrete mixing design depending on fibers quantity has been done. This mixing design was obtained after several experiments and scientific research that may need more investigations in further studies. It is recommended that the durability of light transmitting concrete be investigated in future research and many tests such as permeability and corrosion intensity be performed on them. It is hoped that by using the results of this study, a step forward will be taken for the development of light transmitting concrete in the world and it can help to use this concrete in the construction industry more often than in the past.

CRediT authorship contribution statement

Danial Navabi: Conceptualization, Methodology, Carrying out the

Fig. 12. Compressive strength of light transmitting concrete samples.

Fig. 13. Occupy a large volume of concrete by PMMA optical fibers.
experiments, Writing - original draft. Mahyar Javidruzi: Data curation, Supervision. Mohammad Reza Hafezi: Visualization, Investigation. Amir Mosavi: Writing - review & editing, Validation, All authors discussed the results and contributed to the final manuscript.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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