You are currently viewing a new version of our website. To view the old version click .
MDPIMDPI
Search all articles
Applied Sciences
Download PDF
  • Article
  • Open Access

5 December 2025

Development of a Laboratory-Integrated Microwave-Assisted Cutting Machine and Its Use in Carbonate Rocks

,
,
,
,
and
1
Graduate School of Science and Engineering, Hacettepe University, Ankara 06532, Türkiye
2
Mining Engineering Department, Hacettepe University, Ankara 06532, Türkiye
3
Department of Mining Engineering, Nigde Omer Halisdemir University, Nigde 51240, Türkiye
4
Geological Engineering Department, Ankara University, Ankara 06100, Türkiye
Appl. Sci.2025, 15(24), 12865;https://doi.org/10.3390/app152412865
This article belongs to the Section Earth Sciences
Version Notes
Order Reprints

Abstract

Full-face tunnel boring machines (TBMs) can be used to excavate hard rocks, but there are still significant issues with low advance rate and high cutter wear. However, roadheaders and other mechanical excavators are unable to cut hard rocks. Research on microwave-assisted excavation has gained attention recently in an effort to decrease cutter wear, increase the TBM advance rate in hard rock excavation, and enable the mechanical excavation of hard rocks using machines other than TBMs. Nevertheless, neither a laboratory nor a field-based integrated microwave-assisted excavation machine is currently in use. The present paper aims to examine the cuttability of carbonate rock samples in the laboratory using an integrated microwave-assisted linear cutting machine which has just been developed. Samples of carbonate rock were gathered from Türkiye and Romania, and both untreated and treated samples underwent cutting tests with a pointed pick. For both non-microwave and microwave-assisted cutting experiments, optimum specific energy values for each sample were determined. During microwaving at 15 kW, when comparing optimum specific energy values to those of non-microwave cutting, notable decreases were seen. The evaluation of the findings demonstrated the economic viability of cutting carbonate rocks with microwave assistance.

1. Introduction

Calcium carbonate or calcite (CaCO3) is found in the form of chalk, limestone, marble, and dolomite. It is harmless to human beings and the environment. In many countries, it has also been used for enriching soil and decreasing the acidity of dirty lakes. In addition, it is an exceptional mineral which is essential for humans, animals, and plants. On the other hand, calcite is an industrial raw material and is used in many sectors such as paint, paper, plastic, textile, food, medicine, etc. Calcite is produced from carbonate rocks by crushing and grinding. The carbonate rocks are generally excavated by the drilling and blasting method. Rock blasting is a challenging method compared to mechanical excavation. It also has some limitations due to environmental problems and formal procedures. However, the mechanical excavation of hard rocks is not possible and not efficient. For this reason, there is no surface application for the mechanical excavation of medium- and hard-strength rocks in the world. Some companies which produce calcite want to increase their production rate and are looking for a new eco-efficient excavation method. Carbonate rocks generally have medium or high strength, which is difficult, if not impossible, to mine by mechanical excavators. Some carbonate rocks look as if they can be excavated by mechanical miners. However, it will probably be uneconomical to do so, as the production rate will be low for the calcite plants. For this reason, there is no application for the mechanical excavation of carbonate rocks at quarries and open pit mines. Surface miners have been used in some areas. But their cutting capacity is limited and the production rate is low for medium- or high-strength rocks. On the other hand, they are used for the excavation of large flat and horizontal rock layers, which are not always found in most of the quarries or open pit mines. Continuous miners or drum miners are used for the excavation soft minerals (coal, potash, salt, etc.) in underground mines. They are not used in the surface excavations due to the fact that their cutting performance is limited for medium-strength and hard rocks. The objective of this study is to reveal the cuttability of carbonate rocks by microwave-assisted continuous miners equipped with point-attack picks.
In rock engineering projects, mechanical excavators or the drilling and blasting method are used to excavate rock masses. When conditions are suitable, mechanical excavation has been used extensively for rock excavation because it offers a number of benefits over drilling and blasting. Mechanized excavation has certain disadvantages, even though it offers many benefits for mining and tunneling. The two main issues with excavating extremely hard and abrasive rocks are high tool wear and low advance rate. The machine’s performance declines as worn cutters dramatically raise the cutter forces and the thrust needed for the penetration of the cutters into the rock [1,2]. However, higher cutter loads may cause disk cutter bearings to fail if the abrasive rock is very strong. This could lead to the removal of all the cutters from the tunnel boring machine [3]. Numerous researchers have been investigating cutting-edge techniques like oscillating disk cutting, water jet-assisted excavation, laser jet-assisted excavation, and microwave-assisted excavation in an effort to address these issues. Recently, there has been an increased interest in research on using microwaves to help hard rock cutting. Rocks and minerals are dielectric materials that absorb microwave radiation. The mineralogical characteristics of a rock determine its dielectric constant and, in turn, its heating level. Grain dimension, pore water, irradiation time, microwave power, and microwave energy frequency all have an impact on how much a particular type of rock is heated when exposed to microwave radiation [4,5]. Their heating degrees and thermal expansions will vary because each mineral has a different dielectric constant when exposed to microwave energy. Internal stresses are produced in the rock texture by the minerals’ varying thermal expansions, which lead to fractures in the rock structure.
Numerous experts have examined how microwaving affects the strength and fracture formation of rocks in order to establish a foundation for its possible application to mechanized excavation [6,7,8,9,10,11,12,13,14,15,16,17,18]. According to their findings, microwaving weakens rock samples and causes cracks based on mineralogical composition, microwave power, and radiation duration. Recently, Wang et al. [19] studied the dynamic fracture mechanical properties of dry and saturated rocks under the action of microwave illumination. They stated that saturated sandstone exhibited a more rapid heating response and significantly lower dynamic fracture toughness and fracture energy compared to dry samples after microwave irradiation. Wang et al. [20] also investigated the thermo-mechanical degradation behavior and fracture evolution mechanisms of low-permeability coal under the influence of cyclic heating and liquid nitrogen cooling. They concluded that cyclic thermal shock causes an 81.98% decrease in coal’s P-wave velocity, a 63.31% reduction in tensile strength, and an 85.15% attenuation in fracture toughness.
Lindroth et al. [21] presented the fundamental design for the microwave radiation of a rock block before cutting and obtained a patent for their design. The patent document only offered a theoretical explanation of how rock is treated with microwaves during excavation. There has not been any field or laboratory application of the technique. Despite the 1991 patent, there has not been any research conducted on the topic in a long time.
After reviewing the research on how microwave exposure affects typical hard rocks’ strength properties, Hassani and Nekoovaght [22] proposed a potential designation for a microwave assistance system for the cutting head of a tunnel boring machine. Hassani et al. [11] designed a site model for the microwaving of rocks by piling up twelve slabbed basalt samples with a thickness of 2 cm and treated them with microwaves at 3000 W power for 60–120 s. The experiments indicated that both wet and dried basalt slabs had a measured penetration depth of about 5 cm. After exposing a dried basalt sample at a distance of 3 cm from the antenna to 120 s of radiation, the topmost slab exhibited the highest density of macrocracks. It was revealed that the microwave-assisted rock excavation process was both practical and attainable.
Hartlieb and Grafe [23] microwaved the large blocks of a granitic rock at 24 kW power for a duration of thirty seconds. Then, they cut the block with a conical cutter and measured cutting forces. They found that there was a roughly 10% decrease in cutting forces. In an additional investigation, Hartlieb et al. [24] demonstrated that granite’s cutter forces and specific energy (SE) values dropped by 22% and 6.3–29.8%, respectively, after 45 s of exposure to 24 kW of power. Shepel et al. [25] performed multivariable regression analysis for the assessment of forces when cutting a prismatic granite block exposed to high-powered microwaves. To estimate the cutting forces, they created multiple regression models that included the depth of cut, exposure duration, and the interval between cuts. Feng et al. [26] patented the cutting head of a hard-rock tunnel boring machine equipped with magnetrons to generate microwaves. Kahraman et al. [27] investigated how mineralogical properties affected the cuttability of several magmatic rock types with microwave assistance. They concluded that mineralogical properties such as mineral types and percentages are the key factors during the microwave heating of rocks. The same two rock types from different locations are affected to different degrees by the microwaves because of their different mineral properties, and therefore their cutting behaviors change.
Feng et al. [28] designed a testing mechanism to cut rocks with a microwave-aided system. The primary components of the mechanism are a high-power microwave system, a dual-mode cutting system, and a true-triaxial system. Basalt blocks were subjected to a rotational cutting test after microwaving at various radiation levels under true-triaxial loading conditions. It was found that the primary determinants of cutting were the true-triaxial stress magnitude, cutter head drive stress, microwaving power, and exposure duration.
Lin et al. [29] introduced a hard rock fracturing system propelled by high-power microwaves. They first examined the heating properties and variations in the ore’s reflection properties using various microwave parameters to determine the optimum microwave parameters to be used. After that, the ore was exposed to radiation using the idealized parameters. The field tests carried out in the Sishanling Iron Mine demonstrated that mechanical excavation supported by high-power microwaves was feasible.
Ning et al. [30] examined how the microwave irradiation affected a disk cutter’s ability to crush basalt. They revealed that cutter forces and cutting SE could be efficiently decreased after microwave irradiation. It was stated that the utilization of microwave-assisted breakage using a cutting tool was posited as a potentially fruitful and advantageous technique.
This literature review shows that microwave-assisted cutting tests were carried out only on igneous rocks such as granite, basalt, and andesite. There is no study on microwave-assisted cutting tests on carbonate rocks. Since carbonate rocks are mineralogically very different from igneous rocks, their reaction to microwave energy will be different. In this study, an integrated microwave-assisted laboratory cutting machine has been developed and the cuttability of carbonate rocks with conical cutters was investigated.

2. Materials and Methods

2.1. Sampling

Carbonate rock blocks with dimensions of 30–40 cm were gathered from eight distinct places in Türkiye and Romania to use in the experimental works. The rock types consisted of six marbles and two limestones (Table 1). This study was primarily based on a project concerning the cuttability of marbles. Because the primary objective of the project was to assess the cuttability of marble, marble samples were selected first. Two limestone samples were also added to further enhance the project.
Table 1. Carbonate rocks included in the experiments.

2.2. Mineralogy

To determine the mineralogical properties under a polarizing microscope, thin sections of each type of rock were prepared. The mineralogical characteristics, including composition, structure, and texture, are listed in Table 2.
Table 2. Mineralogical properties of the samples.

2.3. Microwave-Assisted Rock Cutting System

A microwave-assisted rock cutting system was designed and constructed for laboratory cutting tests as part of a research project [31]. The general layout and side view of the system are indicated in Figure 1 and Figure 2. The details of the cutting unit are also given in Figure 3. The system includes a magnetron that can reach a maximum power of 25 kW and operates at the frequency of 915 MHz. A conical cutter or disk cutter can be used in the system for rock cutting tests.
Figure 1. The general layout of the microwave-assisted rock cutting system.
Figure 2. The side view of the microwave-assisted rock cutting system.
Figure 3. The details of the cutting unit.

2.4. Rock Mechanics Experiments

Density and porosity tests were first conducted on the core specimens of the rocks under investigation. The specimens were subjected to strength tests such as uniaxial compressive strength (UCS) and Brazilian tensile strength (BTS) tests. Procedures recommended by the ISRM [32] were used for testing. Table 3 presents the average test results together with standard deviations. UCS and BTS tests were repeated at least five times for each rock type. Density and porosity tests were repeated at least three times for each rock type.
Table 3. The physico-mechanical test results of the specimens.

2.5. Microwave Treatment Tests

Four blocks of dimensions around 25 cm × 18 cm × 10 cm were cut from every kind of rock with a diamond saw to be used in cutting experiments. Three blocks were individually microwaved for 180 s at 5, 10, and 15 kW of power for every kind of rock. An infrared thermometer was utilized for measuring the surface temperature of every block. The temperature measurements were performed both before and after the blocks were exposed to microwave radiation. Both untreated and treated samples were stored at room temperature to ensure that their moisture contents were not different.

2.6. Linear Cutting Tests

Using cement-based grouts, each prismatic sample was bonded into a steel box and allowed to set for a day prior to testing (Figure 4). The conical cutter was used to trim the samples’ surfaces before the cutting test. Spacing (s) between each cutting line was selected as 10 mm, and the cutting depths (d) were set at 1, 2, and 4 mm.
Figure 4. Block samples cemented into the steel sample box.
Prior to beginning the rock cutting tests, two to three trim passes with the conical cutter were used to create a fresh rock surface, simulating the actual situation of the rock surface in the field. After that, the rock’s surface underwent at least two or three passes, depending on its properties.
During the experiments, a force measurement was made with a dynamometer mounted on top of a conical cutter. Laboratory cutting experiments can be executed either unrelieved or relieved. The relieved method was applied at the velocity of 3 cm/s in the experiments. Since these excavation lines experienced irregular fracture conditions, the forces during the pass’s initial and final cuts were not noted. The data of the start and finish of every pass were also not included in the analysis, in order to eliminate the edge effect. After each cut, the mass was determined by gathering and weighing the fragments. Dividing fragments’ masses by the density of the rock yielded values which were then computed. The average SE values were computed by dividing the cutting force by the volume of the rock excavated after the data from three to five cuts were examined for each depth of cut. Figure 5 displays the two samples’ surface conditions following the cutting test.
Figure 5. Surface view of blocks after cutting experiment: (a) marble (Ruschita), (b) marble (Marmara adası).

3. Results and Discussions

3.1. Assessing the Irradiated Samples’ Surface Temperatures

The specimens’ surface temperatures are plotted against microwave power in Figure 6. Every tested rock, with the exception of Baschioi limestone (Code 7), exhibits a roughly linear temperature increase as microwave power increases. Baschioi limestone has a non-linear temperature increase and reaches a higher temperature (225 °C) than other rocks. This is due to the fact that is has high porosity (19 percent) and consequently a high moisture content. After 10 kW of power, the temperature does not increase much, probably because the moisture inside evaporates. The temperatures of rocks other than Baschioi limestone at 15 kW power vary from 84.42 °C to 146.9 °C. It is essential to bear in mind that the measured temperature values pertain to the surfaces of the specimens. Nevertheless, when a substance is exposed to microwaves, its interior temperature rises above its surface temperature, as microwaves heat objects from within [5,33]. As per the findings of Hartlieb et al. [33], a basalt specimen’s inner temperature was 440 °C, while its exterior temperature was 250 °C. Consequently, it may be concluded that the investigated materials’ internal temperatures are probably higher than their surface temperatures.
Figure 6. Specimens’ surface temperatures in relation to microwave power (the rock codes are indicated by the numerals).
For high-porosity Baschioi limestone (Code #1), the curve tends to flatten above 10 kW, which is reasonable due to the drying effect. This sample is thought to lose moisture more rapidly and reach thermal equilibrium above 10 kW due to its very high porosity. Other rocks with low or very low porosity will probably reach thermal equilibrium above 15 kW.
Although the tested rocks have the same mineral content (CaCO3), their surface temperatures are quite different. This is because rocks of the same class and similar mineral content have different textural properties and, even if in small amounts, different minerals. On the other hand, the microwave heating characteristics of the rock are reflected in a number of other factors, including grain size, mixture percentage, water content, ambient temperature, and the applied microwave power and frequency. Even a small amount of metallic minerals may increase the temperature of the sample too much [18].

3.2. Assessing Cutting Test Results

Figure 7 displays the SE values plotted against microwave power. Since optimum spacing-to-depth (s/d) ratio values for Marble (Gümüşler-3) and Marble (Sazlıca) samples were obtained at a 4 mm cutting depth at all power values, the curves of these two parameters coincide. SE values generally decrease with increasing microwave power. While SE-decrease is low in Marble (Sazlıca) and Limestone (Amasya) samples, decreases are high in other rocks. The fastest decrease is seen in Marble (Ruschita) and Limestone (Baschioi) samples.
Figure 7. The specific energy as a function of microwave powers.
To see the changes in SE depending on the s/d ratio for different microwave powers, the graphs given in Figure 8 were drawn. In these graphs, it is seen that optimum specific energy (SEopt) values decrease as microwave power increases.
Figure 8. Relationships between SE and spacing-to-depth ratio for varying microwave powers.
SEopt values obtained from the cutting experiments performed before and after exposure to microwaves at 15 kW power and SEopt loss values after exposure to microwaves are shown in Table 4. After exposure to microwaves, significant decreases were observed in SEopt values. SEopt loss values ranged from 18.9% to 50.5%. The highest SEopt loss (50.5%) in the Limestone (Baschioi) sample is thought to be due to the fact that this rock has a higher moisture content than other rocks due to its high porosity. Additionally, this sample contains limonite mineral. Calcite, the main mineral in limestone, has a dielectric constant of 6.36, while limonite has a dielectric constant of 6.95 [34]. It is thought that the limonite content, in addition to high porosity, also has an effect on the high SEopt loss. Marble (Ruschita) also has a high SEopt loss. This is due to the fact that this sample contains graphite mineral, which has a very high dielectric constant (>81) [34].
Table 4. SEopt and SEopt loss values for the treatment duration of 15 kW.
Some other tested rocks without high porosity or high microwave absorbing minerals also have quite high SEopt losses. This is likely due to the fact that, in addition to mineral content and porosity, grain density, mineral size, and textural properties also affect the dielectric properties of the rocks. Furthermore, vein structures containing metallic minerals (FeO, AlO), found in rocks composed mostly of calcite mineral, such as marble and limestone, also increase microwave absorption capacity [29].
Apart from the rock and mineral properties, microwave heating is affected by microwave power, frequency, exposure time, ambient temperature, distance to the antenna, and cavity type (single or multimode). In the experiments, all parameters except rock properties and power were held constant. SEopt loss data were evaluated for 15 kW (Table 4). SEopt values were obtained under optimal conditions at different cutting depths at a constant spacing distance.

3.3. Economic Considerations

To determine the overall energy expenditure, SE consumed by microwave application must typically be added to SE needed for cutting. But during microwave treatment, only a very small portion of the block is cut, even though the entire block is heated. The energy required to heat only the cut slice cannot therefore be calculated. However, considering the possible field application, the following approach has been developed:
In microwave energy applications, penetration depth is an important parameter. In the measurements performed by Motlagh [10], the penetration depth for calcite (marble) at the frequency of 1 GHz was measured as 15 m. Since the frequency used in this study (915 MHz) is very close to the value of 1000 MHz, a penetration depth of 15 m can be used. Since the outlet size of wave guide is 22 cm × 18 cm, according to the penetration depth of 15 m, the volume to be heated in the field is calculated as follows (normally, the microwave will be distributed over a wider area and the wider area will be heated. However, since the effective area is unknown, this situation is not taken into account in the calculation. Furthermore, in a potential field application, the entire heated volume will be repeatedly cut after microwave application. The following evaluation takes this into account):
The volume to be heated = 0.22 m × 0.18 m × 15 m = 0.594 m3
The energy consumed by applying 15 kW power for 180 s can be calculated as follows:
The consumed energy = 15 kW × 180 s/3600 h = 0.75 kWh
The microwave-specific energy is also calculated as follows:
The microwave-specific energy = 0.75 kWh/0.594 m3 = 1.26 kWh/m3
When calculating the total energy consumption for microwave-assisted excavation, the microwave SE value must be added to the microwave-assisted cutting test SE value. When the 1.26 kWh/m3 value is added to the SEopt values in Table 3, there are still significant SEopt losses. In this case, it is clear that microwave-assisted excavation is economical.
Another important point is that, since the particle size is much smaller in mechanized excavation compared to blasting, crushing costs will also be greatly reduced. In addition, less energy will be spent for crushing and grinding since the excavated material was exposed to microwaves, and again the cost will decrease. In addition, it can be said that the reduction in waiting times due to blasting, the elimination of some limitations, and the absence of environmental damage compensation will also contribute to cost reductions.

4. Conclusions

An integrated microwave-assisted laboratory cutting machine has been introduced and the cuttability of carbonate rocks with conical cutters was studied. The following can be stated in light of the study’s findings:
  • The developed microwave-assisted laboratory cutting machine can be reliably used for the microwaving and cutting of rocks.
  • The SE and SEopt values decline significantly with increasing microwave power.
  • Significant SEopt losses were observed in the samples after microwave exposure. SEopt losses reaching 50% were observed at 15 kW power.
In conclusion, it can be said that microwave-assisted cutting of carbonate rocks is economically feasible. The benefits of excavation without blasting and the benefits of crushing and grinding following the microwave-assisted excavation application should be considered in a comprehensive study that is carried out in the future.

Author Contributions

Conceptualization, S.K.; methodology, S.K.; formal analysis, S.K., M.R.G. and R.C.; investigation, S.K. and M.R.G.; data curation, M.R.G., R.C., M.F., A.A. and F.D.P.; writing—original draft preparation, S.K.; writing—review and editing, R.C. and M.F.; project administration, S.K.; funding acquisition, S.K. All authors have read and agreed to the published version of the manuscript. This paper is a part of the Ph.D. thesis of M.R.G.

Funding

The authors would like to thank the European Union through the ERA-NET Cofund on Raw Materials (ERA-MIN 2) (Reference Number: ERA-MIN-2018_95).

Institutional Review Board Statement

Not applicable.

Data Availability Statement

The raw data supporting the conclusions of this article will be made available by the authors on request.

Conflicts of Interest

The authors declare no conflicts of interest.

Abbreviations

The following abbreviations are used in this manuscript:
TBMFull-face tunnel boring machine
UCSUniaxial compressive strength
BTSBrazilian tensile strength
ISRMInternational Society for Rock Mechanics and Rock Engineering

References

  1. Zhang, G.; Dang, W.; Herbst, M.; Song, Z. Complex analysis of rock cutting with consideration of rock tool interaction using distinct element method (DEM). Geomech. Eng. 2020, 20, 421–432. [Google Scholar] [CrossRef]
  2. Chang, S.-H.; Lee, C.; Kang, T.-H.; Ha, T.; Choi, S.-W. Effect of hardfacing on wear reduction of pick cutters under mixed rock conditions. Geomech. Eng. 2017, 13, 141–159. [Google Scholar] [CrossRef]
  3. Rostami, J. Performance prediction of hard rock Tunnel Boring Machines (TBMs) in difficult ground. Tunn. Undergr. Space Technol. 2016, 57, 173–182. [Google Scholar] [CrossRef]
  4. Santamarina, C. Rock excavation with microwaves: A literature review. In Proceedings of the 1989 ASCE Foundation Engineering, Evanston, IL, USA, 25–29 June 1989; pp. 459–473. Available online: https://cedb.asce.org/CEDBsearch/record.jsp?dockey=0060982 (accessed on 21 October 2025).
  5. Peinsitt, T.; Kuchar, F.; Hartlieb, P.; Moser, P.; Kargl, H.; Restner, U.; Sifferlinger, N.A. Microwave heating of dry and water saturated basalt, granite and sandstone. Int. J. Min. Miner. Eng. 2010, 2, 18–29. [Google Scholar] [CrossRef]
  6. Satish, H. Exploring Microwave Assisted Rock Breakage for Possible Space Mining Applications. Master’s Thesis, McGill University, Montreal, QC, Canada, 2005. Available online: https://escholarship.mcgill.ca/concern/theses/pz50gw73f (accessed on 12 October 2025).
  7. Satish, H.; Ouellet, J.; Raghavan, V.; Radziszewski, P. Investigating microwave assisted rock breakage for possible space mining applications. Min. Technol. 2006, 115, 34–40. [Google Scholar] [CrossRef]
  8. Motlagh, P.N. An Investigation on the Influence of Microwave Energy on Basic Mechanical Properties of Hard Rocks. Master’s Thesis, Concordia University, Montreal, QC, Canada, 2009. Available online: https://spectrum.library.concordia.ca/976521/ (accessed on 5 September 2025).
  9. Nejati, H.; Hassani, F.; Radziszewski, P. Experimental Investigating of Fracture Toughness Reduction and Fracture Development in Basalt Specimens under Microwave Illumination. In Proceedings of the 13th ASCE Aerospace Division Conference on Engineering, Science, Construction, and Operations in Challenging Environments, Pasadena, CA, USA, 15–18 April 2012; pp. 325–334. [Google Scholar] [CrossRef]
  10. Motlagh, P.N. Physical and Mechanical Properties of Rocks Exposed to Microwave Irradiation: Potential Application to Tunnel Boring. Ph.D. Thesis, McGill University, Montreal, QC, Canada, 2015. Available online: https://escholarship.mcgill.ca/concern/theses/xg94hs56k (accessed on 16 September 2025).
  11. Hassani, F.; Nekoovaght, P.M.; Gharib, N. The influence of microwave irradiation on rocks for microwave assisted underground excavation. J. Rock Mech. Geotech. Eng. 2016, 8, 1–15. [Google Scholar] [CrossRef]
  12. Lu, G.; Li, Y.; Hassani, F.; Zhang, X. The influence of microwave irradiation on thermal properties of main rock-forming minerals. Appl. Therm. Eng. 2017, 112, 1523–1532. [Google Scholar] [CrossRef]
  13. Zheng, Y.L.; Zhang, Q.B.; Zhao, J. Effect of microwave treatment on thermal and ultrasonic properties of gabbro. Appl. Therm. Eng. 2017, 127, 359–369. [Google Scholar] [CrossRef]
  14. Lu, G.; Feng, X.; Li, Y.; Hassani, F.; Zhang, X. Experimental Investigation on the Effects of Microwave Treatment on Basalt Heating, Mechanical Strength, and Fragmentation. Rock Mech. Rock Eng. 2019, 52, 2535–2549. [Google Scholar] [CrossRef]
  15. Zeng, J.; Hu, O.; Chen, Y.; Shu, X.; Chen, S.; He, L.; Tang, H.; Lu, X. Experimental investigation on structural evolution of granite at high temperature induced by microwave irradiation. Mineral. Petrol. 2019, 113, 745–754. [Google Scholar] [CrossRef]
  16. Bisai, R.; Palaniappan, S.K.; Pal, S.K. Influence of individual and combined pre-treatment on the strength properties of granite and sandstone. Arab. J. Geosci. 2020, 3, 7. [Google Scholar] [CrossRef]
  17. Lu, G.; Feng, X.; Li, Y.; Zhang, X. Influence of microwave treatment on mechanical behaviour of compact basalts under different confining pressures. J. Rock Mech. Geotech. Eng. 2020, 12, 213–222. [Google Scholar] [CrossRef]
  18. Kahraman, S.; Canpolat, A.N.; Fener, M. The influence of microwave treatment on the compressive and tensile strength of igneous rocks. Int. J. Rock Mech. Min. Sci. 2020, 129, 104303. [Google Scholar] [CrossRef]
  19. Wang, P.; Lin, Y.; Chen, D.; Yin, T. Dynamic Mode I Fracture Toughness and Damage Mechanism of Dry and Saturated Sandstone Subject to Microwave Radiation. Appl. Sci. 2025, 15, 9500. [Google Scholar] [CrossRef]
  20. Wang, L.; Zhu, L.; Cao, Z.; Liu, J.; Xue, Y.; Wang, P.; Cao, X.; Liu, Y. Thermo-mechanical degradation and fracture evolution in low-permeability coal subjected to cyclic heating–cryogenic cooling. Phys. Fluids 2025, 37, 086617. [Google Scholar] [CrossRef]
  21. Lindroth, D.P.; Morrell, R.J.; Blair, J.R. Microwave Assisted Hard Rock Cutting. United States Patent No. 5,003,144, 26 March 1991. Available online: https://patents.google.com/patent/US5003144A/en (accessed on 1 July 2025).
  22. Hassani, F.; Nekoovaght, P. The development of microwave assisted machineries to break hard rocks. In Proceedings of the 28th International Symposium on Automation and Robotics in Construction, Seoul, Republic of Korea, 29 June–2 July 2011; pp. 678–684. [Google Scholar] [CrossRef]
  23. Hartlieb, P.; Grafe, B. Experimental Study on Microwave Assisted Hard Rock Cutting of Granite. BHM Berg-Hüttenmänn. Monatsh. 2017, 162, 77–81. [Google Scholar] [CrossRef]
  24. Hartlieb, P.; Grafe, B.; Shepel, T.; Malovyk, A.; Akbari, B. Experimental study on artificially induced crack patterns and their consequences on mechanical excavation processes. Int. J. Rock Mech. Min. Sci. 2017, 100, 160–169. [Google Scholar] [CrossRef]
  25. Shepel, T.; Grafea, B.; Hartliebb, P.; Drebenstedt, C.; Malovyk, A. Evaluation of cutting forces in granite treated with microwaves on the basis of multiple linear regression analysis. Int. J. Rock Mech. Min. Sci. 2018, 107, 69–74. [Google Scholar] [CrossRef]
  26. Feng, X.T.; Lu, G.M.; Li, Y.H.; Zhang, X.W. Cutter Head for Microwave Presplitting Type Hard-Rock Tunnel Boring Machine. United States Patent No. 10,428,654 B2, 2019. Available online: https://patents.google.com/patent/US10428654B2/en (accessed on 15 July 2025).
  27. Kahraman, S.; Sarbangholi, F.S.; Balci, C.; Fener, M.; Karpuz, C.; Comakli, R.; Unver, B.; Ozcelik, Y. The effect of mineralogy on the microwave assisted cutting of igneous rocks. Bull. Eng. Geol. Environ. 2022, 81, 62. [Google Scholar] [CrossRef]
  28. Feng, X.-T.; Su, X.-X.; Yang, C.-X.; Lin, F.; Li, S.-P.; Zhang, J.-Y.; Tong, T.-Y. A Test System for Microwave-Assisted Dual-Mode Mechanical Cutting of Hard Rock Under True Triaxial Compression. Rock Mech. Rock Eng. 2024, 57, 5763–5782. [Google Scholar] [CrossRef]
  29. Lin, F.; Feng, X.-T.; Li, S.; Hai, X.; Zhang, J.; Su, X.; Tong, T.; Song, J. Field test of high-power microwave-assisted mechanical excavation for deep hard iron ore. J. Rock Mech. Geotech. Eng. 2024, 16, 1922–1935. [Google Scholar] [CrossRef]
  30. Ning, B.; Liu, F.; Liu, H.; Xia, Y. Experimental study on rock breaking using a microwave-assisted tunnel boring machine cutter. Bull. Eng. Geol. Environ. 2024, 83, 114. [Google Scholar] [CrossRef]
  31. Kahraman, S.; Fener, M.; Comakli, R.; Buldak, S.; Andras, A. Investigating the Microwave Assisted Cutting of Carbonate Rocks; Research Project; the European Union Through the ERA-NET Cofund on Raw Materials (ERA-MIN 2) (Reference Number: ERA-MIN-2018_95); ERA Learn: Hamburg, Germany, 2024. [Google Scholar]
  32. Ulusay, R.; Hudson, J.A. (Eds.) The Complete ISRM Suggested Methods for Rock Characterization, Testing and Monitoring: 1974–2006. Suggested Methods Prepared by the Commission on Testing Methods, International Society for Rock Mechanics; ISRM Turkish National Group: Ankara, Turkey, 2007. [Google Scholar]
  33. Hartlieb, P.; Leindl, M.; Kuchar, F.; Antretter, T.; Moser, P. Damage of basalt induced by microwave irradiation. Miner. Eng. 2012, 31, 82–89. [Google Scholar] [CrossRef]
  34. Rosenholtz, J.L.; Smith, D.T. The dielectric constant of mineral powders. Am. Mineral. J. Earth Planet. Mater. 1936, 21, 115–120. [Google Scholar]
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Article Metrics

Citations

Article Access Statistics

Journal Statistics
Article metric data becomes available approximately 24 hours after publication online.
Download PDF
Optimized Quaternary Binder Systems for Sustainable High-Performance Concrete: Insights from Taguchi Design
Previous
GNSS Vector Networks in a Local Conventional Reference Frame
Next