Search Results (89)

Granite formations provide suitable geological conditions for building gravity dams. However, the presence of intruding granite creates a fractured zone. The interaction of this fractured zone with structural planes and faults can create geological conditions that are unfavorable for the anti-sliding stability of gravity dams. This paper identifies the dominant structural planes that affect the anti-sliding stability of dams by studying the three-dimensional intersection relationships between groups of structural planes, faults, and fracture zones. The three-dimensional distribution and occurrence of the dominant structural planes directly impact the anti-sliding stability and sliding failure mode of gravity dams. Through comprehensive field investigations and systematic analysis of engineering geological data, the spatial distribution characteristics of structural planes and fracture zones were quantitatively characterized. Subsequently, the potential for deep-seated sliding failure of the gravity dam was rigorously evaluated and conclusively dismissed through application of the rigid body limit equilibrium method. It was established that the sliding mode of the foundation of the dam under this combination of structural planes is primarily shallow sliding. Additionally, based on the engineering geological data of the area around the dam, a three-dimensional finite element numerical model was developed to analyze stress–strain calculations under seepage stress coupling conditions and compared with calculations made without considering seepage stress coupling. The importance of seepage in the anti-sliding stability of the foundation of the dam was determined. The research findings provide engineering insights into enhancing the anti-sliding stability of gravity dams in granite distribution areas by (1) identifying critical structural planes and fracture zones that control sliding behavior, (2) demonstrating the necessity of seepage-stress coupling analysis in stability assessments, and (3) guiding targeted reinforcement measures to mitigate shallow sliding risks. Full article

Lightweight steel-framing (LSF) systems have become increasingly prominent in modern construction due to their structural efficiency, design flexibility, and sustainability. However, traditional facade materials such as stone are often cost-prohibitive, and brick veneers—despite their popularity—pose seismic performance concerns. This study introduces an innovative porcelain sheathing system for cold-formed steel (CFS) shear walls. Porcelain has no veins thus it offers integrated and reliable strength unlike granite. Four full-scale CFS shear walls incorporating screwed porcelain sheathing (SPS) were tested under combined cyclic lateral and constant gravity loading. The experimental program investigated key seismic characteristics, including lateral stiffness and strength, deformation capacity, failure modes, and energy dissipation, to calculate the system response modification factor (R). The test results showed that configurations with horizontal sheathing, double mid-studs, and three blocking rows improved performance, achieving up to 21.1 kN lateral resistance and 2.5% drift capacity. The average R-factor was 4.2, which exceeds the current design code values (AISI S213: R = 3; AS/NZS 4600: R = 2), suggesting the enhanced seismic resilience of the SPS-CFS system. This study also proposes design improvements to reduce the risk of brittle failure and enhance inelastic behavior. In addition, the results inform discussions on permissible building heights and contribute to the advancement of CFS design codes for seismic regions. Full article

The data on the volumetric radon activity of the Akchatau territory were systematized in the context of radioecological safety. Radon (Rn²²² and Rn²²⁰) and indoor radon (isotopes Po, Pb, and Bi) make a significant contribution to radon radiation in residential and industrial premises. Increased radon concentration in a number of areas is associated with the Akchatau tungsten–molybdenum mine. The source of radon in geological terms is acid leucocratic granites in the northwestern and southeastern parts of the studied territory. Seasonal assessment of radon radiation was carried out using modern devices “Alfarad Plus” and “Ramon-Radon”. Frequency analysis of the average annual equivalent equilibrium concentration (EEC) in 181 premises showed that only in 47.5% of the premises does the volumetric radon activity not exceed the current standards (200 Bq/m³). Differentiated values of radon concentration were obtained in cases where daily and seasonal observations were carried out. In 43.1% of premises, the effective dose varies from 6.6 mSv/year to 33 mSv/year, and for 9.4% of premises, from 33 mSv/year to 680 mSv/year. The increased radon concentration is caused by high exhalation from the soil surface, the radioactivity of building materials, and low air exchange in the surveyed premises. In the northwestern part of Akchatau, anomalous zones were found where the exposure dose rate of gamma radiation exceeds 0.6 mkSv/hour. An objective assessment of radon largely depends on a number of factors that take into account the geological, technical, atmospheric, and climatic conditions of the region. Therefore, when planning an optimal radon rehabilitation strategy, it is necessary to take the following factors into account: the design features of residential premises and socio-economic conditions. Practical recommendations are given for radiation-ecological and hygienic monitoring of radon safety levels in the environment to reduce effective doses on the population. Full article

Long-term exposure to radon, thoron, and gamma radiation from building materials poses a significant health risk to occupants. Current methods for estimating radiation doses often fail to consider the combined impact of these sources. Based on commonly used building materials available on the Irish market, this paper advocates for the development of a comprehensive dose estimation model that accounts for radon, thoron, and gamma radiation. To achieve this, several models and various scenarios (e.g., ventilation conditions and building characteristics) are integrated to convert radon and thoron gas doses into a common unit recognized in the existing literature. This approach enables the comparison of combined dose values with accepted radiation thresholds for building materials, typically set at 1 mSv, alongside data on material compositions. Previous studies suggested gamma radiation doses in Irish materials are unlikely to exceed 1 mSv annually. Our findings confirm this, showing gamma doses <0.4 mSv for all materials. However, combined radon–thoron doses exceeded thresholds in altered granites (e.g., Galway granite: 3.90 mSv), with thoron contributing ≤93% of total exposure due to uranium/thorium-rich minerals (e.g., monazite, zircon). Ventilation proved critical—high airflow (10 m³/h) reduced thoron doses by 90–95%, while current gamma-focused safety indices (I-index ≤ 1) inadequately addressed combined risks. These results highlight the previously underestimated importance of thoron and the necessity of multi-parameter models for regulatory compliance. The study establishes a novel framework to evaluate holistic radiation risks, urging revised standards that prioritize ventilation strategies and material mineralogy to protect public health in residential and commercial built environments. Full article

The construction field is one of the largest sectors and industries worldwide. This industry is the main industry accused of contributing to greenhouse gases and increasing the effects of climate change. However, the construction industry is indispensable, accordingly in an attempt to decrease the greenhouse gas effects of construction this research presents the manuscript for building a one-story building with all components including waste products. The building model used a strip foundation with a concrete mix design incorporating recycled concrete as a partial replacement for aggregates, cement hollow blocks containing granite waste instead of conventional cement blocks, and sandwiched insulated panels made of wood-plastic composites for the roof. The structural soundness of the system was tested by loading it with a load surpassing its design load in addition to measuring the deflection and checking its abidance to the code limitations. The thermal efficiency was tested by measuring the temperatures in comparison with the outside of the building for a span of 7 days with data recorded every 1 h. Analysis of both the short-term and long-term costs and carbon emissions was performed by acquiring the carbon emissions per unit of material from literature and multiplying it by the quantities of the materials used within the different building alternatives. That study showed that the roofs made of Structural Insulated Panels (SIPs) using Wood-Plastic Composite (WPC) facings when used with hollow-block cement block walls have shown enduring cost efficiency and improved thermal insulation, leading to diminished energy usage, life-cycle expenses, and carbon emissions. Furthermore, the proposed system is more environmentally friendly than conventional reinforced concrete technologies due to their lower costs and emissions in addition to improving sustainability through utilizing recycled materials. Full article

The application of energy-saving policies in buildings could lead to a decrease in the air exchange rate in dwellings, which could consequently lead to an increase in indoor radon concentration and, therefore, to an increase in resident exposure to ionizing radiation. The aim of the research presented in this paper is to investigate radiological exposure to residents due to the usage of different granites commonly used in Serbia as a building material. From the total of 10 analysed granite samples, a wide range of radon and thoron exhalation rates were found: from <161 μBq m⁻² s⁻¹ to 5220 ± 200 μBq m⁻² s⁻¹ and from <7 mBq m⁻² s⁻¹ to 5140 ± 320 mBq m⁻² s⁻¹, respectively. Assuming a low air exchange rate of 0.2 h⁻¹, the contribution of the measured granite material to the indoor radon concentration could go up to 150 Bq m⁻³. The estimated annual effective doses due to exposure to radon and thoron exhalation from the granite samples were (0.05–3.79) mSv and (<0.01–1.74) mSv, respectively. The specific activity of radionuclides ranged from 6.6 ± 0.5 Bq kg⁻¹ to 131.8 ± 9.4 Bq kg⁻¹ for ²²⁶Ra, from 0.5 ± 0.1 Bq kg⁻¹ to 120.8 ± 6.5 Bq kg⁻¹ for ²³²Th, and from 0.22 ± 0.01 Bq kg⁻¹ to 1321 ± 86 Bq kg⁻¹ for ⁴⁰K. The obtained external hazard index ranged from 0.03 to 1.48, with three samples above or very close to the accepted safety limit of 1. In particular, dwellings with a low air exchange rate (causing elevated radon) could lead to an elevated risk of radiation exposure. Full article

The land section of the Huangdao end of the Jiaozhou Bay Second Submarine Tunnel is extensively underlain by the Quaternary Loose Accumulation Layer. The tunnel passes through a weathered granite fracture zone with well-developed rock joints beneath the buildings. The tunnel excavation process significantly disturbs the buildings above, making them prone to settlement, cracking, and tilting. This research conducts numerical simulations of three tunnel excavation methods, and based on the results, compares the deformation behaviors of the ground surface and buildings under various conditions. The findings show that the double side-wall guide pit method has better adaptability in controlling surface settlement and building deformation than the vertical or curved CD method. Moreover, the removal of temporary supports significantly affects building settlement and tilt; this risk can be effectively reduced by controlling the stress relief ratio during the removal phase of the temporary supports in the tunnel. The significance of the study lies in the fact that by choosing an appropriate tunnel excavation support scheme, the disturbance impact on the overlying buildings can be minimized, and the construction safety and stability of the surrounding buildings can be guaranteed. The results of this study can provide initial guidance for constructing shallow-buried tunnels beneath existing buildings. Full article

Demolition of existing buildings turns building products into waste. The amount of demolition waste is increasing globally. The current case study is an example of fulfilling the EU Waste Framework Directive of reducing demolition waste by reuse of historical materials in their original structures. The aim of this paper is to investigate construction materials from 19th and 20th centuries and their mechanical and physical properties in a case study building from the conservation area of Võru city, South Estonia. Timber structures of the case study building were non-destructively tested on-site using a resistive method. Ceramic brick plinth and basement walls, as well as concrete and granite ceiling, were tested in situ non-destructively (rebound hammer test) for compressive strength estimation. Previously dismantled timber logs, slats and ceramic bricks were tested in the laboratory for compression and bending, respectively. The logs and slats matched the European timber bending strength classes C22 and C40, respectively. The compressive strength of the studied ceramic bricks was comparable to that of newly produced bricks. The non-destructive moisture content of timber structures varied in spring (5–20%) but was steady in the autumn (5–7%) tests. The rebound hammer test overestimated by 1.5…2 times the compressive strength of the studied materials compared to laboratory tests. Full article

This study aims to incorporate building and demolition waste, including lime and crushed granite, as partial alternatives for cement and fine aggregates, respectively, and to devise a plan to reduce their environmental effect resulting from their extensive prevalence in substantial amounts. The use of lime in paste, mortar, and concrete has become a common practice to regulate the environment, save resources, and improve performance in various settings. The first stage of this study investigated the effects of replacing different proportions (0%, 15%, 25%, 35%, and 50%) of lime powder with cement on the physical and mechanical properties of mortar specimens over 7, 28, and 90 days. The next phase of the research examined the impacts of substituting varying quantities (ranging from 10% to 100%) of granite powder in 15 different mixes, while keeping a consistent water-to-binder ratio of 0.45. The last part of the study consisted of an examination of data from previous research on cement mortar and lime-modified cement mortar. This included testing on flowability, standard consistency, setting time, flexural strength, and compressive strength. The acquired data underwent a statistical analysis, which resulted in the development of equations that may predict the mechanical characteristics of changed cement mortar mixes. These equations also highlight the impact of certain physical qualities on compressive and flexural strength. Full article

The Zheduo–Gongga Mountain, an enormous tower located at the boundary of the eastern Tibetan Plateau, is an ideal place to study the contribution of the climate and/or tectonics to the mountain building. Here, we report new zircon U–Pb ages, biotite ⁴⁰Ar–³⁹Ar, and apatite fission track (AFT) ages of granites along the Zhonggu transect in the northern part of the Zheduo–Gongga massif to investigate the detailed exhumation history and mechanism. The results show zircon U-Pb ages of 14.3 ± 0.3 and 11.3 ± 0.2 Ma, Biotite ⁴⁰Ar–³⁹Ar ages of 4.39 ± 0.07 and 3.62 ± 0.05 Ma, and AFT ages of ~2.6–0.9 Ma. Combining previous structural and geochronological studies, we argue that the growth and exhumation of the Zheduo–Gongga Mountain experienced the following stages. Late Oligocene–early Miocene crust shortening and magmatism marked the initiation of the crustal thickening and surface uplift during ~32–11 Ma, forming a migmatite–granitic belt along the Xianhuihe fault, in response to the northward advancing of the Indian plate into the Eurasian plates. Subsequently, the massif experienced episodic phases of exhumation with variable rates. The exhumation occurred at a rate of ~1–1.5 km/Ma with a cooling rate of 70 ± 20 °C/m.y. during ~11–5 Ma coinciding with the coeval intensification of the Asian monsoon and clockwise rotation of the Chuandian block, south of the Xianshuihe fault. During ~5–2 Ma, a phase of accelerated exhumation (~2–5 km/Ma) started, followed by a possible phase of decelerated exhumation (~1–1.5 km/Ma, corresponding to a cooling rate of 120 ± 20 °C/m.y.) since ~2 Ma, when alpine glaciations initiated due to global cooling. This study highlights the importance of tectonic deformation during ~11–5 Ma in controlling the early growth and exhumation of high mountains in the eastern Tibetan Plateau. The climate may account for the later exhumation of the Zheduo–Gongga mountain since ~5 Ma. Full article

This study aimed to investigate the feasibility of using geopolymer paste (GP) as an adhesive agent for (i) anchoring steel bars in concrete substrates, (ii) repairing concrete, and (iii) repairing limestone and granite masonry blocks commonly found in historic buildings. In this investigation, seven cement-free GP mixes were developed with different combinations of binder materials (slag, silica fume, and metakaolin). The mechanical properties, adhesive performance, and production cost of the developed GP mixes were compared to those of a commercially epoxy adhesive mortar (EAM). The results obtained from this study indicated that the use of GPs enhanced the bonding between steel bars and concrete substrates, achieving bonding strengths that were 19.7% to 49.2% higher than those of control specimens with steel bars directly installed during casting. In concrete repairs, the GPs were able to restore about 60.6% to 87.9% of the original capacity of the control beams. Furthermore, GPs exhibited a promising performance in repairing limestone and granite masonry blocks, highlighting their potential suitability for masonry structures. The best adhesive performance was observed when a ternary binder material system consisting of 70% slag, 20% metakaolin and 10% silica fume was used. This combination, compared to the investigated EAM, showed comparable adhesive properties at a significantly low cost, indicating the viability of GPs as a cost-effective, eco-friendly adhesive agent. Full article

Permeability is a crucial parameter in the exploration and development of oil and gas reservoirs, particularly in unconventional ones, where fractures significantly influence storage capacity and fluid flow. This study investigates the fracture permeability of granite reservoirs in the South China Sea, introducing an enhanced evaluation model for planar fracture permeability based on Darcy’s law and Poiseuille’s law. The model incorporates factors such as fracture heterogeneity, tortuosity, angle, and aperture to improve permeability assessments. Building on a single-fracture model, this research integrates mass transfer equations and trigonometric functions to assess intersecting fractures’ permeability. Numerical simulations explore how tortuosity, angle, and aperture affect individual fracture permeability and the influence of relative positioning in intersecting fractures. The model makes key assumptions, including minimal consideration of horizontal stress and the assumption of unidirectional laminar flow in cross-fractures. Granite outcrop samples were systematically collected, followed by full-diameter core drilling. A range of planar models with varying fracture apertures were designed, and permeability measurements were conducted using the AU-TOSCAN-II multifunctional core scanner with a steady-state gas injection method. The results showed consistency between the improved model and experimental findings regarding the effects of fracture aperture and angle on permeability, confirming the model’s accuracy in reflecting the fractures’ influence on reservoir flow capacity. For intersecting fractures, a comparative analysis of core X-ray computed tomography (X-CT) scanning results and experimental outcomes highlighted discrepancies between actual permeability measurements and theoretical simulations based on tortuosity and aperture variations. Limitations exist, particularly for cross-fractures, where quantifying complexity is challenging, leading to potential discrepancies between simulation and experimental results. Further comparisons between core experiments and logging responses are necessary for model refinement. In response to the challenges associated with evaluating absolute permeability in fractured reservoirs, this study presents a novel theoretical assessment model that considers both single and intersecting fractures. The model’s validity is demonstrated through actual core experiments, confirming the effectiveness of the single-fracture model while highlighting the need for further refinement of the dual-fracture model. The findings provide scientific support for the exploration and development of granite reservoirs in the South China Sea and establish a foundation for permeability predictions in other complex fractured reservoir systems, thereby advancing the field of fracture permeability assessment. Full article

Bioreceptivity measures the ability of a surface to develop and maintain a permanent ecosystem of microorganisms. In the historic built environment, this is characterised visually by the greening of monuments and other outdoor heritage. Primary and secondary bioreceptivity refer to the potential for biological growth on fresh and weathered stone, respectively. Measuring bioreceptivity helps us understand biological growth rates and allows researchers to characterise the impact of stone conservation treatments on colonisation. Understanding the relative bioreceptivity of stones allows heritage professionals to make more informed selection of replacement stone types for repairs to existing structures. The primary bioreceptivity of stones from different geographical areas cannot currently be easily compared due to a lack of consistency in approaches to measurement. We propose a repeatable lab-based methodology for measuring colour and chlorophyll a levels from a standard algal culture grown on the stone surface as a standardised testing protocol for primary and secondary bioreceptivity. This protocol controls for the effects of mineralogical colour change during testing, which is something that has not been addressed in other methodologies. This method was successfully applied to case studies measuring the bioreceptivity of English granite, sandstone and limestone, determining their position in a bioreceptivity index. Our results demonstrated that for the stones tested, primary bioreceptivity was categorised as very low or low. Secondary bioreceptivity was increased compared to primary bioreceptivity. This research is the first to fully categorise any stones for secondary bioreceptivity and provides the first primary and secondary bioreceptivity data for any UK stones. We encourage others to follow this standard protocol to add additional data and build an international bioreceptivity database accessible to heritage practitioners. Full article

To estimate the expected damage due to rockfalls and debris flows for buildings and people, it is essential to assess the response of brick walls to boulder impacts. There are scarce physical tests of the impact of boulders on brick walls, which are typical of residential buildings. A simple and low-cost experimental setup for investigating the damage of unreinforced brick walls that are subjected to a boulder’s impact is presented. The setup consists of a ramp that is adjusted with a light steel structure. Seven pilot tests for five single-leaf brick walls of a 1000 × 1000 mm² area, hit by a 72.925 kg granite boulder, and from five release heights (0.25 m, 0.50, 1.00 m, 2.50 m, and 3.00 m) are performed. The observed damage indicates that wall breakthrough occurs for translational kinetic energies as low as 500 J. The prevalent failure mechanism is local shear damage. Additionally, a numerical model to simulate the physical tests was developed using the FEM. Using the same properties as in the physical testing, the numerical model is found to realistically reproduce the displacement of a node at the centre of the impact, as well as the translational impact velocity and energy, for the same five boulder release heights. Full article

The growing interest in the use of building materials with a reduced carbon footprint was the aim of this research assessing the impact of four different types of low-emission cements on the properties of cement concretes used for the construction of local roads. This research work attempted to verify the strength characteristics and assess the durability of such solutions, which used the commonly used CEM I 42.5 R pure clinker cement and three multi-component cements: CEM II/A-V 42.5 R, CEM III/A 42.5 N-LH/HSR/NA, and CEM V/A S-V 42.5 N-LH/HSR/NA. Cement was used in a constant amount of 360 kg/m³, sand of 0/2 mm, and granite aggregate fractions of 2/8 and 8/16 mm. This research was carried out in two areas: the first concerned strength tests and the second focused on the area of assessing the durability of concrete in terms of frost resistance F150, resistance to de-icing agents, water penetration under pressure, and an analysis of the air entrainment structure in concrete according to the PN EN 480-11 standard. Analyzing the obtained test results, it can be concluded that the highest compressive strength of more than 70 MPa was obtained for CEM III concrete, 68 MPa for CEM V concrete, and the lowest for CEM I cement after 90 days. After the durability tests, it was found that the smallest decrease in compressive strength after 150 freezing and thawing cycles was obtained for CEM III (−0.9%) and CEM V (−1.4%) concretes. The high durability of concrete is confirmed by water penetration tests under pressure, because for newly designed recipes using CEM II, CEM III, and CEM V, water penetration from 17 mm to 18 mm was achieved, which proves the very high tightness of the concrete. The assessment of the durability of low-emission cements was confirmed by tests of resistance to de-icing agents and the aeration structure performed under a microscope in accordance with the requirements of the PN-EN 480-11 standard. The obtained analysis results indicate the correct structure and minimal spacing of air bubbles in the concrete, which confirms and guarantees the durability of concrete intended for road construction. Concretes designed using CEM V cement are characterized by a carbon footprint reduction of 36%, and for the mixture based on CEM III, we even observed a decrease of 39% compared to traditional concrete. Concrete using CEM II, CEM III, and CEM V cements can be successfully used for the construction of local roads. Therefore, it is necessary to consider changing the requirements of the technical specifications recommended for roads in Poland. Full article