Mechanical Properties Of Building Materials Research Articles

Field Test and Numerical Study of Train-Induced Vibration of Over-Track Buildings Above Metro Depot

To maximize the use of urban land, many cities have built buildings above metro depots. However, the low-frequency vibration caused by metro operation affects the lives of surrounding residents, which seriously restricts the further development of over-track buildings. To study this problem, Firstly, the vibration of the metro depot and surrounding sensitive areas are tested on a large actual metro depot in Southwest China, and the rail, sleeper/support column, bearing column, and cover plate are mainly tested. Then, considering nonlinear factors such as mechanical properties of building materials, soil layering characteristics, and artificial viscoelastic boundary, the numerical coupled model of the train-track-depot-building is established, and the simulation data are compared with the test data to verify the accuracy of the numerical model. Finally, the impact of metro operation on the over-track buildings is evaluated. Results show that for the over-track buildings concerned in this paper, the floor vibration near the rail is the strongest, the main vibration frequency of the office building is concentrated in 10–20 Hz, and the maximum Z vibration level (VLzmax) of the office building is 52.02 dB. The main vibration frequency of the residential building is similar to that of the office building, and the superposition of floor vibration energy causes the vibration of the mid-span point to be larger than the vibration of the corner point and the side wall point. The vibration wave of lower floors mainly propagates through the bearing column, and the vibration of the parking garage is larger than other buildings. The research results can provide a reference for the vibration control and design of over-track buildings above the metro depot.

Optimization of mechanical properties for intelligent building materials combining with various steel fiber types and nano-Carbon black

The mechanical properties of building materials has emerged as a novel application criterion. However, the investigation of the influence of different steel fibers (SFs) types and nano-carbon black (CB) on the mechanical properties of intelligent building materials remains limited. In this paper, an orthogonal test is conducted to analyze the mechanical performance of building materials with various types of SF and different factors of SFs and CB content. The single-phase results reveal that the optimal content of SFs for intelligent building materials ranges from 0.20%∼0.80% when combined with air content and mechanical performance indicators, while the CB content range ranges from 0.25 wt%∼0.75 wt%. Additionally, the study employs the orthogonal experimental method to determine the mix proportion for intelligent building materials. The experiment selected orthogonal design conditions with four levels and three factors (including SF types and contents and CB content) and conducts range analysis and variance analysis on the experimental results of each group. The results demonstrate that the compressive strength and splitting tensile strength of building materials are optimized when the contents of shear-type SFs and CB are 0.40% and 0.75 wt%, respectively.

Preparation of high-performance materials based on carbon nanofibers and analysis of mechanical properties at room and high temperatures

The shortcomings of conventional building materials, such as inadequate tensile strength and fire resistance, have been significantly exacerbated with the emergence of complex and diverse engineering practices. However, the current research on high-performance building materials is still in its nascent stage. Therefore, our study aims to investigate the potential improvements in the mechanical properties of building materials through the incorporation of carbon fiber and nano silica. Specifically, we focus on assessing the mechanical properties of these modified materials at both room and elevated temperatures. Our experimental results demonstrate a notable enhancement in compressive strength. At room temperature, the H2 group exhibited a 15.1% increase in compressive strength, while the H5 group experienced a 7.3% increase. Notably, the compressive strength of the H7 group reached its highest value at 47.13 MPa. Additionally, the H2 group displayed the highest bending strength at 5.18 MPa. Our electron scanning microscopy analysis revealed the uniform dispersion of carbon fibers within the building materials, without any clumping. This suggests that when the dosage of Carbon Fiber reaches 0.6% of the mass of building materials, it can be uniformly dispersed within the mixture. We have also evaluated the performance of the modified materials under high temperatures. It was observed that the prefabricated building materials group experienced a 65% reduction in compressive strength when subjected to 800 °C. Conversely, the carbon fiber building materials exhibited a compressive strength loss of over 62%. Overall, the carbon fiber building materials outperformed the standard building materials under high temperature conditions, with significantly higher compressive strength. Moreover, the modified materials demonstrated an improvement in the residual splitting strength, ranging from 26% to 37% when exposed to temperatures over 800 °C. These findings indicate a substantial enhancement in the mechanical properties of the proposed modified materials. In conclusion, the incorporation of carbon fiber and nano silica into the building materials resulted in substantial improvements in their mechanical properties. These modified materials hold great potential for practical construction projects, offering higher performance and enhanced durability.

Құрылыс 3D басып шығару технологиясында қалдық негізіндегі модификациялық қоспаларды пайдалану

The introduction of innovative 3D printing technologies in the construction industry makes it possible to increase the efficiency and environmental sustainability of materials. In parallel with the development of this technology, there was a need to create modification mixtures using waste materials. This study examines the use of waste-based modification additives in construction 3D printing technology. The main physico-mechanical properties and strength of fine-grained concretes formed by the method of layered extrusion show the high efficiency of using a modification mixture in the production of cements, mortars and concretes with a given complex of rheotechnological properties, depending on the composition of raw materials mixtures, interaction conditions and conditions. In the course of the study, the properties of waste materials are studied and the possibility of their use in the composition of building mixtures used for 3D printing is analyzed. Various experiments were carried out in order to determine the efficiency of waste materials and their effect on the physical and mechanical properties of building materials. As a result, it was found that waste-based modification additives contribute to increasing the strength, stability and environmental friendliness of building materials in construction 3D printing technology. It aims to provide new opportunities and solutions in the construction sector, considering the environmental benefits and economic benefits of these approaches.

Research trends in phase change materials (PCM) for high-performance sustainable construction

In the face of escalating environmental perils driven by climate change and global warming, there is an urgent call for innovative and sustainable energy solutions, especially within the construction sector, which is a major consumer of energy and emitter of greenhouse gases. Among various energy-efficient interventions, Phase Change Materials (PCMs) have emerged as a promising technology for passive thermal regulation in buildings. This review paper delves into recent advancements in integrating PCMs within building envelopes, which serve to store thermal energy, thus reducing temperature fluctuations and enhancing indoor comfort levels. The study also underscores the increasing global demand for energy storage systems in pursuit of a low-carbon economy and how PCMs can address this imperative. A special focus is given to applications of PCMs in diverse climatic zones, and the paper offers insights into the thermo-physical properties that make them amenable for building integration. Furthermore, the paper reveals that paraffin wax is the most extensively used PCM and discusses the relevance of selecting PCMs based on their melting points, which is pivotal for optimizing heat transfer efficiency. This study also highlights the need for extensive real-world, full-scale evaluations of PCMs, and the importance of scrutinizing their impact on the mechanical properties of building materials. The lifecycle and cost analyses of PCM integration, which are often overlooked, are identified as crucial areas for further research. Through a comprehensive review of global applications and experimental findings, this paper accentuates the potential of PCMs in revolutionizing building energy efficiency, cooling-heating systems, and integration in concrete, mortar, walls, and solar energy applications while also calling for continued research into performance enhancement and understanding potential drawbacks. This underscores the pivotal role of PCMs in steering the construction industry towards sustainability and energy conservation.

Influence of innovative technologies on the physical and mechanical properties of building materials in the construction industry

A multifunctional additive based on a gel-like dispersion of taunitic carbon nanomaterial (CNM) is considered. The influence of its quantitative composition on the physical and mechanical properties of fine-grained concrete is studied. The results of a study of the frost resistance of fine-grained concrete enriched with a gel-like dispersion of CNM "Taunit" are presented.The main hypotheses describing the formation of the porous structure of concrete under the action of alternate freezing and thawing are considered, and the influence features of the structure of nanomodified concrete on its frost resistance and density. Nano-modified fine-grained concrete was tested by scanning microscopy, which shows that the process of forming changes in its structure occurs not only as a result of reinforcement, but also as a result of growth crystalline hydrates, the centers of which are particles of CNM "Taunit".

ДО ПИТАННЯ ЗАБЕЗПЕЧЕННЯ БЕЗПЕКИ ЕКСПЛУАТАЦІЇ БУДІВЕЛЬ І СПОРУД В УМОВАХ ВИСОКИХ ТЕМПЕРАТУР

Purpose. Determination of the influence of technical characteristics of building materials and structures when assessing the safety of operation of buildings and structures in conditions of elevated temperatures. Methodology. During the research, the following methods were used: methods of determining the fire hazard of building materials; standard methods of testing the physical and mechanical properties of building materials; analysis of literary sources and statistical analysis (classification of building materials according to degree of flammability and properties; physical property of burning of various building materials; physico-chemical process of flame propagation during burning of various building materials by stages); etc. Results. It has been determined that foreign methods of testing materials and structures are not universal and do not allow to fully obtain the necessary information from the tested material, which complicates the real assessment of their technical characteristics, including fire safety, and requires improvement. From the point of view of labor protection and safety, our analysis of the fire hazard of construction materials and structures showed that the problem of ensuring labor protection at enterprises due to fire protection concerns a number of structures made of concrete and reinforced concrete, asbestos cement, brick, metal, wood, plastics, etc. This problem is most relevant for structures made of metal (steel and aluminum alloys), wood, plastics, and more and more recently used translucent facade structures. Scientific novelty. The main areas of ensuring the safe operation of buildings and structures, taking into account state regulations, have been determined. Practical significance. A comprehensive assessment of the safety of the operation of buildings and structures, building materials and structures under the influence of high temperatures has been carried out.

Контроль физико-механических свойств строительных материалов по альтернативному признаку

A method for applying alternative control of the physical and mechanical properties of building materials is proposed as a way to increase the reliability of structures under construction. The accuracy of existing quality control methods is analyzed. Directions for solving the problem of improving the quality control of building materials are proposed. A relationship is established between strength properties assessed in the frames of the currently used procedures and the elasticity modulus, the assessment of which is the basics of the proposed alternative control method. The technical feasibility of using the new method is described. The features of control by the alternative attribute of the mechanical properties of the material are defined and the technical feasibility of such control on the example of concrete is formulated. A control system is proposed which envisages the use, in conjunction with the quality control by compressive strength, the control by elasticity modulus.

ANALYSIS OF TEST EQUIPMENT FOR INVESTIGATION OF MATERIALS UNDER A STRONG LOAD APPLICATION

An analysis of modern testing equipment to establish the mechanical properties of different in structure and origin of building materials. As a result, it was established, that the most effective for testing are foreign electromechanical and servo-hydraulic machines of different configurations. It is determined that this type of technical systems allows to study different types of materials, including high-strength, compressive, tensile, bending and other types of loads in accordance with current international regulations. The article analyzes the principles of operation of the universal test machine INSTRON and the universal servo test machine UIT STM 100S. The configuration of such modern technical systems involves the availability of electronic computers and software, which allows testing in automatic mode, program research factors, determine the current and maximum values of mechanical properties of building materials, perform mathematical calculation of characteristics, reproduce information on the device screen, build research diagrams in electronic and printed form. It has been found that the advantages of such test machines are a load of up to 60 tons. It was determined that the universal machine UIT STM 100S is characterized by a large traverse stroke and a wide range of test speeds, which allows to expand the solution of quality control problems in industry. It is also established that the UIT STM 100S has software that includes a standard library of test methods according to regulatory documentation. The advantages of such a machine are the possible expansion of the standard information base necessary for the operation of the standards or the installation of an additional software module that provides the ability into independently supplement the standard library. Given the wide range of measurements of the universal testing machine UIT STM 100S, we envisage its use for the study of deciduous and coniferous wood in modern rigid test mode.

Glass powder admixture effect on the dynamic properties of concrete, multi-excitation method

In this work, the dynamic properties of a high performance concrete containing glass powder (GP) was studied. The GP is a new cementitious material obtained by recycling waste glass presenting pozzolanic activity. This eco-friendly material was incorporated in concrete mixes by replacing 20 and 30% of cement. The mechanical properties of building materials highly affect the response of the structure under dynamic actions. First, the resonant vibration frequencies were measured on concrete plate with free boundary conditions after 14, 28 and 90 curing days by using an alternative vibration monitoring technique. This technique measures the average frequencies of several excitations done at different points of the plate. This approach takes into account the heterogeneity of a material like concrete. So, the results should be more precise and reliable. For measuring the bending and torsion resonant frequencies, as well as the damping ratio. The dynamic properties of material such as dynamic elastic modulus and dynamic shear modulus were determined by modelling the plate on the finite element software ANSYS. Also, the instantaneous aroused frequency method and ultrasound method were used to determine the dynamic elastic modulus for comparison purpose, with the results obtained from vibration monitoring technique.

Instrumented dynamic tests of building materials

In some specific cases, the building structures can be exposed to extreme dynamic loads. Namely, it can be car crash, earthquake or the effect of explosion. For these cases, it is useful to know the dynamic mechanical properties of building materials. The paper presents two unique procedures for instrumented impact testing of building materials (concrete and sandstone). These tests may help in practice with selection of suitable materials for buildings and structures which may be threatened by dynamic effects of mechanical stresses. The method how to achieve a higher dynamic material stability is also presented.

The Use of Reftinskaya State District Power Plant Fly Ash in the Production of Building Materials and Products

The system of dry ash–slag removal at the Reftinskaya state district power plant which provides capture, storage and shipment of fly ash to the consumers is considered in this study. The results of determination of chemical and phase composition, physical properties, melting temperature and activity of natural radionuclides of ash which is form during burning of stone coal of Ekibastuz basin are presented. Ash is acidic, superfine and refractory one with a low content of combustible substance. As to composition and properties it satisfies the requirements of Russian Standard no. 25818 and ships to consumers under Technical Conditions 5717–004–79935691–2009. The results of laboratory tests and industrial production of building materials and products on the basis of ash of Reftinskaya state district power plant are presented. It is shown that ash is used in the production of Portland cement, heavy and cellular autoclave concrete, dry mixes and can also be used as part of fly ash non-fired and agloporite gravel, ceramic bricks. The features of their production, basic physical and mechanical properties of building materials and products are described. It is shown that the introduction of a new system of dry ash removal at the state district power plant contributes to the expansion of directions and increase in the volume of ash recycling.
 Keywords: Reftinskaya state district power plant, dry ash removal, fly ash, composition, properties, use, construction materials and products

Investigation of Physical and Mechanical Properties of Construction Materials of Forced Carbonate Hardening

A technique for determining the modulus of elasticity of сonstruction materials on samples of small dimensions has been developed. Physical and mechanical properties of building materials based on calcareous-lime compositions of semi-dry pressing, hardening according to the principle of forced carbonization, depending on the prescription and technological factors of their production have been studied. It has been demonstrated that on the basis of these materials it is possible to obtain building products with compressive strength up to 30 MPa, tensile strength at bending up to 5 MPa and higher, and an elastic modulus up to 18 GPa.

Influence of man-made aluminosilicate raw materials on physical and mechanical properties of building materials.

It has been identified that man-made aluminosilicate raw materials represented by clay rock of varied genesis can be used as energy-efficient raw materials to obtain efficient highly-hollow non-autoclaved silicate materials. A technique of structure formation in the conditions of pressureless steam treatment has been offered. Cementing compounds of non- autoclaved silicate materials based on man-made aluminosilicate raw materials possess hydraulic properties that are conditioned by the process of further formation and recrystallization of calcium silicate hydrates, which optimizes the ratio between gellike and crystalline components and densifies the cementing compound structure, which leads to improvement of performance characteristics. Increasing the performance characteristics of the obtained products is possible by changing the molding conditions. For this reason, in order to create high-density material packaging and, as a result, to increase the strength properties of the products, it is reasonable to use higher pressure, under which raw brick is formed, which will facilitate the increase of quality of highly-hollow products.

Mechanical properties and durability of bio-blocks with recycled concrete aggregates

Harnessing bio-processes to improve the mechanical properties of building materials have gained interest in developing green construction. One of the bio-processes utilized to improve the mechanical properties of building materials is the bio-mineralization of calcium carbonate by the activity of the urease-positive bacterium. In this research, the recycled concrete aggregates, as one of the main constituents of construction and demolition wastes, were used to produce bio-blocks by the bio-mineralization of CaCO3 and the results were compared to bio-blocks produced with natural aggregates. Furthermore, the durability and mechanical properties of both types of bio-blocks were investigated. The difference in compressive strengths of bio-blocks made with both aggregates was less than 10%. The results showed that bio-mineralization reduced the water absorption of the RCA bio-blocks, which is one of the drawbacks of recycled concrete aggregates. In addition, durability tests revealed that the bio-blocks maintained their strength under freeze thaw cycles and high temperatures.

Effect of Thermal Environment on the Mechanical Behaviors of Building Marble

High temperature and thermal environment can influence the mechanical properties of building materials worked in the civil engineering, for example, concrete, building rock, and steel. This paper examines standard cylindrical building marble specimens (Φ50 × 100 mm) that were treated with high temperatures in two different thermal environments: vacuum (VE) and airiness (AE). Uniaxial compression tests were also carried out on those specimens after heat treatment to study the effect that the thermal environment has on mechanical behaviors. With an increase in temperature, the mechanical behavior of marble in this study indicates a critical temperature of 600°C. Both the peak stress and elasticity modulus were larger for the VE than they were for the AE. The thermal environment has an obvious influence on the mechanical properties, especially at temperatures of 450∼750°C. The failure mode of marble specimens under uniaxial compression is mainly affected by the thermal environment at 600°C.

Effects of moisture on thermal conductivity of the lightened construction material

The major objective of this study is the determination of the physical and mechanical properties of building materials lightened by vegetable fibers, used as heat insulator. An experimental work was set up in order to include/understand and to evaluate the thermo-physical and mechanical characteristics of these materials according to the water content. The experimental results show a significant decrease in the material density and in the thermal parameters with the increase in the percentage of vegetable fibers in the concrete. The results also show the effect of humidity on the thermal conductivity. The composite material studied offers interesting thermal insulation, and consequently an optimal gain of energy in comparison to common construction materials.

Green Manufacture of Building Bricks by Carbonating Steel Slags

Carbon dioxide emission and industrial waste recycling have become hot spots of the world's scientific research, and the preparation of brick in CO2 mineral carbonation of steel slag increased gradually. However, there still exists some questions, such as low strength, low carbonization efficiency. Combined with these problems and according to the previous experimental basis, this study aims to further improve the carbonation efficiency and mechanical properties of building materials. In this paper, it studied the influence of carbonization pressure in the preparation of steel slag bricks as building materials by CO2 mineral carbonation. The results show that the optimal carbonization pressure is about 0.25MPa. Under the process parameters, the carbonization efficiency and the compressive strength is 16.6% and 65.1MPa respectively.

Software Implementation of the Algorithm the Statistical Straggling of the Mechanical Properties of Materials in the Design of Structures

The random character of mechanical properties of building materials reveals itself when construction structures are tested even though all prescribed technological standards and requirements are met. The paper presents software implementation of the algorithm the statistical straggling of the mechanical properties of materials in the design of structures. This algorithm is built into the software AnSysBuildingBlock (ASBB), developed by us, whose interface is presented here, and which can automatically generate the code for the settlement complex ANSYS. Consider an example in which the impact of scattering mortar mechanical properties on the stress-strained state of brick masonry and its structural destruction was investigated.

Using finite element methods to analyze ancient architecture: an example from the North American Arctic

Developing theories of vernacular architecture in archaeology has been hindered by the lack of a defined methodology for studying ancient buildings, and the absence of information on the mechanical properties of construction materials uncommon in today's building practices. In this paper we use Finite Element Methods and recent research on the structural properties of whalebone to analyze the architecture of Thule semi-subterranean houses. These unique dwellings were constructed and used by the ancestors of Inuit/Eskimo peoples in the Canadian Arctic and Greenland. Little is known about how they were designed and constructed because few have ever been discovered intact. The substantial weight of whalebone roof frames suggests that some designs would have performed better than others. Poorly planned houses, or the use of whalebone in a symbolic rather than strictly utilitarian capacity, may have resulted in higher maintenance costs, thereby shortening their anticipated use life. In extreme cases, errors in design, or the failure of materials may have caused dwellings to collapse, resulting in injuries or possibly even death. We demonstrate through this case study that Finite Element Methods constitutes an effective methodology for studying ancient buildings, with the proviso that more research is needed on the mechanical properties of building materials used in the past.