Natural Stone Research Articles

Laboratory evaluation of a complex treatment technology for reducing water absorption of the pavement subbase aggregate from the blast-furnace slag

When smelting each ton of pig iron, approximately 500 kg of blast-furnace slag is formed and requires recycling. Air-cooled blast-furnace slag can be used for the manufacture of slag aggregate for the pavement subbase layers, as an alternative to natural stone aggregate. The wide use of slag in this area is limited by its high water absorption. This paper proposes a complex technology to reduce water absorption of slag aggregate. This technology includes selective crushing, which allows separating low-porosity aggregate grains from high-porosity ones, and impregnation of selected low-porosity grains with hydrophobic agent (surface hydrophobization). The results of a laboratory evaluation of this technology effectiveness are presented. Article also contains optimal parameters of this complex technological process which allowed to reduce the water absorption of the slag aggregate from 4.54% to 1.05%.

Resistance of natural stone masonry wallettes under centred and eccentric compressive loading: Experimental and numerical approaches

Masonry walls are typically subjected to eccentric compressive loadings in common buildings. However, the design of walls towards this type of solicitation remains very empirical, often leading to oversizing the structure. This is especially true for natural stone masonry, for which experimental data are quite scarce. This paper presents an experimental campaign on 15 natural stone masonry wallettes subjected to centred and eccentric compression until failure. Different values of the eccentricity of the load, ranging from h/12 to h/4 (where h is the thickness of the wallette) were investigated, highlighting the noticeable effect of such a value on the compressive failure load. During the tests, the displacements were recorded by a Digital Image Correlation system, providing insights into the different failure mechanisms that depend on the value of the eccentricity. The so-obtained experimental failure loads are then compared to the predictions of Eurocode 6. Finally, a finite-element yield-design analysis of these tests is proposed which shows that this modelling framework is suitable to find the ultimate bearing capacity of a masonry wallette.

Hydrophobic Coatings’ Efficiency and Limestones’ Resistance to Salt Crystallisation

Stone deterioration is significantly influenced by the process of salt crystallisation. The expansion of salt crystals on a porous framework exerts pressure on the solid fraction, causing the stone to deteriorate when the internal pressure of salt surpasses the stone’s strength. Protective coatings are employed to effectively hinder or substantially reduce the penetration of water and saline solutions. This study attempts to evaluate the effectiveness and long-term durability of limestones protected with hydrophobic coatings, focusing on their resistance to salt damage. The investigation followed the specifications set by the standard EN 12370:2019 and EN 14147:2003, which assesses the resistance of natural stone to salt crystallisation. The findings of this study indicate the conservation of physical–mechanical properties after ageing tests. In parallel, measurements of the static contact angle and the measurement of quality indexes revealed that the coatings maintained a certain level of hydrophobicity even after undergoing salt weathering tests, maintaining the good quality of the stones.

Application of Pebbles for Geotechnical Seismic Isolation (GSI): Experimental Parametric Study

Low-income regions do not have the economic strength to use conventional isolators; therefore, low-cost alternatives are needed. The recent series of earthquakes in Turkey has once again demonstrated the destructive power of this natural disaster and highlighted the need for high-quality earthquake-resistant structures. In this context, a comprehensive experimental parametric study on the use of natural stone pebbles (ASL-1) and stone pebbles in combination with a geogrid layer (ASL-2) as suitable materials for a GSI system is conducted and the main results are presented. The seismic behavior of five different models was tested using four different acceleration diagrams with different peak ground accelerations (PGAs). Characteristic displacements, accelerations, and strains were measured. The results and conclusions presented are based on the integration and synthesis of several previously conducted studies.

Model tests on ordinary and geosynthetic encased stone columns with recycled aggregates as filler material

PurposeSincethe availability of natural aggregates is very sparse, recycled industrial and construction waste provides a sustainable alternative to ground improvement using vibro replacement method. Utilizing recycled building waste caters the requirement for its disposal and offers an effective remedy for the scarcity of natural resources. The aim of this study was to give a sustainable alternative for the natural aggregates as the material for stone column.Materials and methodsA good stone column material should be hard, dense, chemically inert and must comply with the size requirement. The utilization of construction debris and spent railway ballast as column material has been the subject of numerous researches. This work focuses on finding the suitability of railway ballast and concrete debris as alternatives for stone column material. A detailed laboratory testing of these materials has been carried to judge their strength requirements as the material for both Ordinary Stone Columns (OSCs) and Geosynthetic Encased Stone Columns (GESCs). The improvement in capacity of both OSCs and GESCs is evaluated by performing California Bearing Ratio (CBR) test in laboratory by creating unit cell stone column models of different recycled aggregates and comparing their load settlement behavior with natural aggregates.Results and discussionRailway ballast, natural aggregates, concrete debris and virgin soil were found to show decreasing order in CBR test results. Loading required for causing settlement in both OSCs and GESCsshowed remarkable increase as compared to that of virgin clay and the maximum load settlement improvement was observed for railway ballast in both the types of stone columns. The CBR values for GESC made from railway ballast, natural aggregates and concrete debris were 54, 49 and 38% respectively. On the other hand, CBR for OSC made from railway ballast, concrete debris and natural aggregates were found to be 25.5, 20.4 and 24% respectively and CBR of virgin clay was found to be just 11%.ConclusionThe demonstrated application of sustainable sources in place of natural aggregates provides a crucial pathway for utilizing the recycled aggregates as stone column filler material. Up on encasing the OSC with geotextile the performance of stone columns has improved appreciably in terms of load capacity. Railway ballast and concrete debris can be adopted as an alternate for the natural stone column materials to improve the bearing capacity of site consisting mainly of soft clays.

Particle flow numerical study of size effect on uniaxial compressive strength of natural building stone

The fundamental influence of specimen size and micromechanical parameters on macroscopic structural behavior of natural building stone is investigated by particle flow numerical analysis. Laboratory tests of Dionysos marble cylindrical specimens under uniaxial compressive loading are simulated with a focus on the fracture development, failure mode and uniaxial compressive strength. Two series of simulations are performed with the PFC2D code, one to define the effects of different rates of deformation on the uniaxial compressive strength and fracturing of the specimens and the other to investigate the behavior of the specimens with the variation of five different parameters; platens velocity, specimen size, particle size distribution, standard deviation of randomized shear and normal strength as a micro-parameter and the ratio of shear to normal particle bonding strength. The specimen sizes also include rarely investigated smaller than NX dimensions. On selected specimens, the fracture development and the failure mode is depicted and discussed, and conclusions are drawn about the shear to tensile failure frequency and the crack patterns.

Analysis on determinants of carbon emissions from plaza ground paving during the construction stage based on life cycle assessment

The carbon emissions of paving projects are the focus of urban managers and researchers. By introducing the life cycle assessment (LCA) method and drawing up the study time and boundary, this study analyzed the carbon emissions activities of the plaza ground paving project and established a computational model of the cast-in-place architectural concrete (CAC) and natural stone pavement’s life cycle during the construction stage by comprehensively utilizing the carbon emission coefficient method and the direct source consumption statistics method of the production line. Based on the model, this study employed the ground paving of a top-notch Theme Park Plaza in Beijing as a sample to calculate the carbon emissions of two different types of building materials at various phases of their life cycle and made a comparative evaluation. It is concluded that the carbon emissions (expressed in CO2) produced by the CAC ground in the sample area is 75.46 kg CO2/m2, while that of the natural stone pavement is 110.81 kg CO2/m2. Our results demonstrate significantly linear relationship between the overall emissions of carbon and the material carbon factor. This study adds to the body of knowledge by calculating the carbon emissions and determining the trend of carbon footprint for ground paving. Furthermore, the study's findings can be used to enhance construction management options and choose green materials. The findings can also be used to provide supporting theories for the development of regulations and carbon reduction policies based on constructing energy conservation and greenhouse gas reduction.

Automated construction of multi-leaf walls with natural stones

This paper introduces an innovative strategy for the construction of multi-leaf walls utilizing raw stones, a significant step forward in sustainable building practices. Our approach leverages advanced computational algorithms and image processing techniques to automatically build walls with irregular stones. By focusing on the physical assembly of these materials, the objective is to optimize their use in creating structurally robust walls. The core of our methodology lies in the efficient arrangement of irregular objects based on image-convolution techniques. The proposed packing algorithm is proven to be efficient and versatile in stacking stones without restriction in the shape and size of units. Evaluations of constructed walls based on geometric indices show that the stone layout meets masons’ rules-of-art. This work presents a scalable wall construction solution that could revolutionize the use of natural stones in construction.

Investigation of the mechanical properties of concrete incorporating recycled rubber particles

Quantity of waste rubber generated by automobile tires is growing, posing an environmental threat. Rubber tire recycling was studied for usage in asphalt and waterproofing systems during past few decades. Globally, concrete is the most widely used building material. About 7% of CO2 emissions come from the cement production. The purpose of this research is to assess if using waste rubber and Portland cement together in composite material for structural applications is feasible. Waste tires (shredded to 0/1 mm) were used as fine aggregate replacement (in 2.5 and 7.5 %), together with PC and natural stone. An investigation of properties in fresh (slump test, bulk density, air content) and hardened state (bulk density, compressive strength) was performed on the rubberized concrete. The compressive strength decreased by increasing the rubber content for all w/c ratios (0.55-0.4). The addition of fine-sized rubber did not cause a retardation in cement hydration mechanism. According to the obtained compressive strengths, all designed rubberized concretes belong to a group of structural concretes.

Material properties of building limes for pointing mortar for renovation and restoration of neo-Gothic churches in Sweden

During the neo-Gothic period of the 18th and 19th century, many churches in Sweden were built in brick and natural stone with a traditional lime-based mortar. Moisture- and salt related problems were common in these church buildings, already a few years after they were erected durability problems arose. Examples of these durability problems were internal salt precipitation, leaching of lime-based mortar and other moisture-related deterioration of mortar joints. When these neo-Gothic churches are repointed, this should be done with appropriate traditional lime mortars. However, since the introduction of cement as a material for mortars and renders, the knowledge on lime-based mortars has gradually decreased. Lime as a material for mortar, renders and plasters is still used, but only on a small scale and mostly for work on heritage buildings. There is a knowledge gap regarding material properties and workability of traditional limes. Therefore, the aim of this project was to determine the material properties of lime mortars used for restoration of churches built in brick or natural stone masonry.

ДОСЛІДЖЕННЯ ВПЛИВУ СПОСОБУ ОБРОБКИ НА АДГЕЗІЙНУ ЗДАТНІСТЬ МОНТАЖНИХ ПОВЕРХОНЬ ВИРОБІВ З ПРИРОДНОГО КАМЕНЮ

Purpose. The purpose of the research is to establish the degree of influence of the structural-textural features and the method of processing the facing surface of natural stone products on their ability to adhere. Methodology. To achieve the goal of the research, the following steps were taken: justification and formulation of the hypothesis regarding the dependence of adhesion on the parameters of micro-relief of stone products and the structural-textural features of rock formations; determination and description of the requirements for the samples under investigation; review and brief characterization of the typology of fixing mixtures; selection and description of the main parameters of the mounting surface (base) for fixing the samples under investigation; development of a sequential plan for conducting the research part of the work; actual execution of the research; analysis of the obtained results. Results. Based on the results of the research, the influence of the method of processing the mounting surfaces of stone products on the magnitude of the provided adhesive interaction and the influence of the structural-textural features of natural stone on the adhesion magnitude of adhesive interaction have been established. Scientific novelty. The scientific novelty lies in establishing the relationship between the ability of the surface of natural stone to adhere and the method of its processing; for the first time, the value of adhesion magnitude for the sawn texture of granite from the Didkovytske deposit and gabbro from the Kamyanobridsky deposit has been determined. Practical significance. The practical significance of the obtained results lies in the possibility of using the obtained dependencies for the early prediction of the adhesion magnitude of the surface of facing products made of natural stone to the surface to which they are attached, based on the physical-mechanical properties of the stone and the method of processing its surface. Keywords: adhesion, natural stone, diamond wire sawing, disk sawing, stone product installation.

Analysis of the performance of supply chain resilience strategies using a simulation approach (case study: natural stone industry)

Analysis of the performance of supply chain resilience strategies using a simulation approach (case study: natural stone industry)

Analysis of the performance of supply chain resilience strategies using a simulation approach (case study: natural stone industry)

Analysis of the performance of supply chain resilience strategies using a simulation approach (case study: natural stone industry)

Investigation of granular natural stone materials as photothermal absorbers for sustainable and environmentally friendly energy harvesting

The development of cost-effective and environmentally friendly solar thermal technologies that deliver high performance poses several challenges, where the collector and absorber components play a pivotal role. This research addresses these issues by investigating enhanced temperature generation using a 30 cm × 30 cm Fresnel lens collector under solar illumination from a xenon lamp. Natural stone materials (andesite, coal, and pumice), characterized by granular structures with an average diameter of 1.68-2.00 mm, were selected because of their abundance and eco-friendliness. This research is focused on evaluating the effect of Fresnel lens on temperature generation performance. Two types of temperature generation tests were carried out: wet tests (where the natural stone materials were immersed in distilled water) and dry tests (where the natural stone materials were used in dry conditions). The morphologies of the natural stone materials were examined using an optical microscope and scanning electron microscope. Furthermore, the optical properties of the natural stone materials were analyzed using an ultraviolet-visible (UV-VIS) spectrophotometer. The findings revealed that there were significant improvements in the photothermal absorber performance with the use of a Fresnel lens in dry tests, where the highest temperature was achieved for coal (103.25 °C), followed by andesite (89.00 °C) and pumice (73.00 °C). The impurities varied between the materials, where the impurities were most dominant for pumice while coal was more uniform. Further examination using scanning electron microscope showed that all materials had light-trapping structures in the form of rough surfaces, pores, and crack gaps. Andesite was dominated by rough surfaces, while coal and pumice were dominated by crack gaps and pores, respectively. However, based on the UV-VIS spectrophotometric results, there were no correlations between the optical properties (absorbance, reflectance, and transmittance) and temperature achieved by the photothermal absorber materials. This research demonstrates the potential of using natural stone materials as photothermal absorbers in combination with a Fresnel lens collector for low-to-medium temperature solar thermal applications.

Using the overall variation trend and fitting of Na-feldspar crystal plane spacing after chemical corrosion to prevent rock disasters

Sulfuric acid pollution, caused by acid rain, acidic wastewater, and natural acidic wastewater from mines, poses a significant risk to the stability of natural stone slopes and human stone structures. This study aims to develop a non-mechanical testing method for assessing the degree of acid corrosion in rocks, facilitating early intervention by safety engineers. The proposed method involves using XRD to measure the crystal plane spacing of Na-feldspar corroded by different concentrations of sulfuric acid, followed by mathematical analysis to determine the overall deviation degree of the crystal plane spacing. Four Deviation indices were defined to characterize the degree of acid corrosion, and all four indices increased with increasing acidity. By comparing trend charts, an optimized number of crystal planes for analysis was identified. Selecting the 100 sets of data with the largest spacing yielded similar trend results as selecting all the data. In addition, five different fitting methods were compared, and the power function fitting of Weighted Sum of squares of cumulative errors (WSSCE) was found to provide the optimal empirical formula, with a correlation coefficient exceeding 0.98.

Sustainable supply chain control strategies for the natural stone market

The natural stone market is an important component of the modern economy, with increasing demand driven by a growing population and urbanization. However, the industry faces a range of challenges related to supply chain risk management, including sourcing raw materials, transportation, and quality control. Effective risk management is crucial for the success of any business in this sector, as it helps to minimize losses, maintain quality, and ensure timely delivery of products to customers. This paper proposes the use of a flexible decision-making approach to classify major risks and identify Effective mitigation strategies for order management in the natural stone market. The proposed method considers multiple criteria, including financial, operational, and mitigation factors, to develop a comprehensive risk assessment framework that can be used to optimize control processes. By implementing the proposed framework, stakeholders in the natural stone market can improve their risk management capabilities and enhance their competitive advantage in the global market. The framework can help to identify the most critical risks and prioritize mitigation strategies, resulting in a more efficient and Effective supply chain management system. This paper presents a real case study of a Brazilian company, which illustrates the practical application of the proposed methodological framework in the natural stone market, highlighting its Effectiveness in identifying and mitigating risks related to stone slabs transportation network. The insights gained from this case study have potential for application across various industries facing analogous challenges in managing risks within their supply chains.

МОДЕРНИЗАЦИЯ СТРОИТЕЛЬНО-МОНТАЖНОГО ПИСТОЛЕТА ДЛЯ ДОБЫЧИ ПРИРОДНОГО КАМНЯ

The possibility of mechanizing the operation of wedging for the extraction of natural stone was reviewed. The goal is to reduce the weight of the wedges to several kg and reduce the diameter of the holes in the stone where the wedges are installed. The weight of one hydraulic wedge used is 26 kg, not counting the weight of the hydraulic pump with pressure hoses. Among the options for mechanizing stone mining with wedges, the following approaches are considered – the use of the electro-hydraulic effect; application of liquid nitrogen evaporation in a closed volume; use of electromechanical wedge drive. The fourth option was chosen – modernization of the powder actuated fastening tool for the new task. A calculation has been made for a modernized fastening tool. Several fastening tools chambered for a 7,62 × 54,00 mm rifle cartridge with a charge of moderated propagation gunpowder can split a large stone block. Shallow holes are drilled into the stone block into which wedges are inserted. Measures have been taken to compensate for the recoil of a shot. A shot is fired and the wedges, much larger than a concrete anchor, split the stone. The wedges are reusable. The synchronized operation of several tools is ensured by electric firing from one circuit. A modernized tool with an electric triggering for stone mining can weigh below 3,5 kg. The technical details of the proposal are discussed.

Subbase stabilization with fly ash

Due to increased activities in civil engineering, and especially in the transport infrastructure, and thus an increase in the use of additional construction materials, innovative solutions are needed in finding alternative materials for the preservation of natural resources. One of the solutions for preserving natural building materials is the application of recycled material, which will also meet the required standards in civil engineering. In the transport infrastructure, there is a great opportunity for the use of recycled material, starting from the subbase, through the embankment and all the way to the superstructure and the concrete structures. One of the recycled materials that can be used in construction is fly ash. Fly ash is the most promising waste material when it comes to the wide range of applications in construction. Fly ash is obtained by burning coal in thermal power plants to produce electricity. Due to variations in the composition and characteristics of fly ash, several divisions and classifications have been created. One of the main classifications is according to the American standard ASTM C 618-05 where it is divided into class C and class F fly ash. This research aims to investigate the application of fly ash for subgrade stabilization and to determine the difference from a financial and environmental perspective for the application of fly ash compared to natural stone aggregate. The main research was carried out in connection with the increased use of natural stone aggregate, which appeared as a need during the rehabilitation of state road R1206, section Karpalak - Zelino. Apart from the use of large quantities of stone aggregate for the stabilization of the subgrade, it also had an impact on the financial framework for the realization of the road project. In Macedonia, an analysis of the chemical composition of 4 samples of fly ash obtained in REC Bitola was carried out. From the obtained results, it can be concluded that it belongs to the classification of F-class fly ash and with the use of an activator (lime or cement) it can be used in the stabilization of the subgrade.

Feasibility Analysis of a Roof Tile Factory Business Using a Capital Budgeting Approach

Natural content that supports the need for raw materials and materials needed is provided by the nature around us, such as various plants, soil, water, natural stones, and others. Most of them can be further processed into raw materials for construction products, such as roof tiles and other infrastructure facilities. The financial feasibility aspect is important considering that the business can be categorized as a project, which requires a long payback period based on the accounting period. During this time period there are various things that are full of uncertainty which are influenced by the rate of inflation and bank interest rates, so that the value of investments issued and the income or money obtained now will be different from the value of money in the future, which is called with the value of time rather than money. It is hoped that the analytical tool will be able to provide consideration, input and anticipation for the future of the roof tile manufacturing unit project by paying attention to capital budgeting, which can then be analyzed from a financial aspect through payback period (PP), net present value (NPV), profitability index ( PI) and internal rate of return (IRR). In the roof tile manufacturing business, the PBP is 1 year, 8 months, 6 days faster than the maximum period of 8 years of the project value, positive NPV of IDR 536,821,468, PI of 2,841 greater than number 1 and IRR of 14,835 greater than the cost value of capital 12%. As a basis for decision making through a capital budgeting approach through financial analysis.

Damage Types and Repair Techniques in Seljuk Period Stone Architectural Monuments: Konya Alaaddin Mosque

In order to determine the correct conservation and repair techniques for stone architectural monuments, it is necessary to determine the types of damage that occur in the stone. The determination of damage types is directly related to the factors that cause damage. In this study, the factors that cause deterioration in natural stones and the types of weathering were classified through literature research. Through the literature review, different repair techniques depending on the type of deterioration were examined. A field study was carried out based on the data obtained from the research conducted within the scope of the study. Alaaddin Mosque, one of the Seljuk period stone architectural monumental buildings located in Konya city centre and whose restoration works have been completed in recent years, was selected to be examined. In order to obtain information about the conservation and repair activities applied in the building, the archive of Konya Regional Directorate of Foundations, which carried out the restoration works, was utilized. The repairs applied to the building were documented by on-site inspection, observation and photography techniques. The observations made during the fieldwork draw attention to the deterioration of the stone materials after the repair activities. In this direction, the deterioration was photographed and classified using the data obtained from the literature. The factors causing the deterioration were analysed and discussed in the results section.