Concrete Test Research Articles

Penggunaan Silika Fume Untuk Reduksi Semen Dengan Limbah Granit Sebagai Pengganti Agregat Kasar Terhadap Kuat Tekan Dan Kuat Tarik Beton

Concrete is a mixture of cement, sand, gravel, and water. In order to obtain good quality in the process, added ingredients, waste, or other materials with a certain ratio value are added. In this case, the use of granite waste as a substitute for coarse aggregate that is easy to find and the use of silica fume which aims to increase the compressive strength of concrete. The purpose of this study was to determine the effect of granite waste and silica fume, as well as the relationship between compressive strength and tensile strength of concrete with these variations. The percentage of granite waste and silica fume varied, ranging from 5%-10% granite waste and 0%, 7.5%, 15%, 22.5%, and 30% silica fume. Concrete testing was carried out after the concrete was 28 days old. The planned compressive strength is 25 Mpa. From the results obtained, the average normal concrete compressive strength was 27.69 Mpa and the average normal concrete tensile strength was 3.14 Mpa. The addition of 5% - 10% percentage granite waste and 0% silica fume obtained an average compressive strength of 27.74 Mpa and 27.65 Mpa, and an average tensile strength of 3.18 Mpa and 3.16 Mpa. The percentage of 10% granite waste and silica fume 7.5%, 15%, 22.5%, and 30% obtained average compressive strengths of 26.42 Mpa, 26.33 Mpa, 25.10 Mpa, and 25.01 Mpa respectively and average tensile strengths of 2.71 Mpa, 2.64 Mpa, 2.50 Mpa, and 2.41 Mpa respectively.

Using Autoclave Concrete Prism Testing to Evaluate ASR Reactivity in Concrete Using Laboratory Tests and Outdoor Exposure Blocks as Benchmark Data

AbstractThe alkali–silica reaction (ASR) occurs in concrete that contains silica in a reactive aggregate, sufficient alkalis, and sufficient moisture. Although the most widely accepted tests for evaluating ASR potential are the concrete prism test (CPT) and the accelerated mortar bar test, each test has limitations. Because of the need to test concrete mixes within a short period of time, an accelerated autoclave test method (autoclaved CPT [ACPT]) was investigated using concrete prism samples boosted to 3.0 % total alkali content subjected to an exposure temperature of 271°F (133°C) with a corresponding pressure of 29 psi (0.2 MPa) for 24 hours. A suite of aggregates was evaluated by concrete prism specimens using both the ACPT and CPT methods. The ACPT was able to classify individual aggregate fractions for ASR reactivity with 97.2 % accuracy for the proposed limit of 0.09 % expansion for 36 tested mixtures and approximately 130 specimens. Data from this test suggest that a week-long test could be considered an effective screening tool for the alkali reactivity of coarse or fine aggregate fractions. In addition, miniature CPT (AASHTO T 380, Standard Method of Test for Potential Alkali Reactivity of Aggregates and Effectiveness of ASR Mitigation Measures (Miniature Concrete Prism Test, MCPT) and 12-year outdoor exposure block results are evaluated and compared with both CPT and ACPT results. Although the data suggest a general agreement between these methods, further testing is warranted along with multi-laboratory precision evaluation.

Mechanical Properties of Rigid Pavements Incorporating Different Percentage of Steel Fiber

Nowadays, rigid pavement construction has widely used in road construction industry. Although rigid pavement is widely used in road construction, it tends to fail within time due to many reasons. Fatigue is the important aspect in the rigid pavement design. Due to applications of the heavy loads fatigue occurs in the pavement in the form of micro cracks. Fatigue concepts which is an important parameter in cement concrete pavement and mainly failure occurs due to fatigue failure. As a result, it is crucial to optimize and improving concrete structures to suit diverse engineering requirements. This paper investigates the effect of steel fiber on the improvement of structural behavior such as compressive, tensile and also flexural stiffness performance of rigid pavements. In this respect, the concrete mix design accordance to Design of Normal Concrete Mix (DOE) method was employed in the preparation of the specimens. A series of concrete laboratory tests have been carried out to evaluate the mechanical properties of the concrete sample incorporating 1, 3 and 5% of steel fiber. As a result, the performance (compressive, tensile and flexural) of modified rigid pavements improved remarkably 15-60% with 5% additive of steel fibre at 7 and 18 days curing time. Based on these studies, the addition of steel fiber reinforcement into the rigid pavements has a significant effect on mechanical properties of reinforced concrete mixture.

Modern concrete composites for earthquake-resistant construction

Objective. The purpose of the research is to develop earthquake-resistant building composites Method. The study is based on experimental dynamic testing of fine-grained concrete. Existing approaches to ensuring seismic safety of buildings and structures are analytically summarized. Result. Domestic and foreign experience in designing fine-grained concrete compositions for earthquake-resistant construction is presented. Compositions of fine-grained concrete of various classes were obtained using raw materials of natural and man-made origin. Recipes were proposed and their construction, technical and dynamic properties were studied. Conclusion. The strength of fine-grained concrete increases with decreasing loading time, and at a loading time of approximately 0.01 sec or a loading rate of about 5000-7000 MPa sec, this excess is about 30% compared to the statistical strength of concrete. This allows us to recommend fine-grained concrete for structures experiencing dynamic impact.

A Subpixel Concrete Crack Measurement Method Based on the Partial Area Effect

To improve the accuracy of concrete crack measurement with a machine vision method in structural health monitoring and in technical status evaluation, a subpixel crack measurement method based on the partial area effect was proposed. (1) First, a pixelwise crack image segmentation method was established through a multi-step process of multi-threshold fusion and morphology operation, and a novel pixel degree crack width calculation method was developed with the extraction of the middle points, the center line and its normal, and the intersection of the center line normal and crack edges. (2) Then, a subpixel algorithm based on the partial area effect was introduced to locate vertical, horizontal, and oblique cracks in subpixel crack edges, and the subpixel crack width could be calculated along the crack center line pixelwise. (3) Finally, the proposed method was verified by indoor concrete beam crack measurement tests with a digital microscope, and the results show that the maximum relative errors of the subpixel width of the horizontal, vertical, and oblique straight cracks measured by the proposed method were 3.06%, 8.97%, and 5.16%, respectively. The absolute error of the crack length was less than 0.30 mm, and the measurement accuracy could reach 0.01 pixels. The subpixel crack measurement method provides a novel possible solution for structural health monitoring.

Ultrahigh-speed imaging for high-impact concrete deformation analysis in pre- and post-cracking stages.

The evaluation of high-speed camera image sequence analysis results in concrete material testing under high-impact loading necessitates the consideration of the effect of the image quality on the measurement accuracy and thus on the potential of the geometric measurements derived from the image sequences. In this contribution, we evaluate the application potential of three ultrahigh-speed cameras with frame rates up to 10Mfps to analyze the deformation of concrete specimens before and after main crack formation in bending and compression tests. Specifically, we evaluate the Kirana 7M and Shimadzu HPV-X2 cameras with ISIS sensor architecture, and the Phantom TMX 7510 camera with BSI CMOS sensor technology. Three-point bending tests and split-Hopkinson pressure bar tests are performed on 160×40×40m m 3 cuboids and on 80mm long, 50mm diameter cylinders. Prior to main crack formation, the displacement vector field represents the specimen deformation, with higher values indicating the position where main cracks will initiate and propagate. Deformations of 80µm in 54µs for a bending test and of 154µm in 36.67µs for a compression test could be measured. The main cracks are then detected using displacement vector field discontinuity analysis techniques, and their evolution is followed to estimate the crack propagation velocity. Average velocities in bending tests between 603 and 854m/s have been determined over a time interval up to 40µs. An investigation of the camera sensor operation of the three optical devices is presented to assess their suitability for deformation analysis. Laboratory tests and real experimental results show that the quality of the propagation vector field, the crack detection, and the crack tip tracking are obviously affected by the image quality, but more significantly by the spatial and temporal resolution due to the small relative step deformations.

Applications of Ultrasonic Detection Technology in Bridge Concrete Pile Foundation Detection

In this paper, the application strategy of ultrasonic detection technology in the detection of concrete foundation piles is analyzed using a construction project as an example. It includes a basic overview of the project, an overview of ultrasonic testing technology in bridge concrete pile foundation testing, and an analysis of its practical application in the concrete pile foundation testing of this project. The objective of this analysis is to provide some reference for the application of ultrasonic testing technology and the improvement of the quality of bridge concrete pile foundation testing.

Automatic testing of runtime enforcers with Test4Enforcers

Users regularly use apps to access services in a range of domains, such as health, productivity, entertainment, and business. The safety and correctness of the runtime behavior of these apps is thus a key concern for users. Indeed, unreliable apps may generate dissatisfaction, frustration and issues to users.Runtime enforcement techniques can be used to implement software enforcers that monitor executions and apply corrective actions when needed, potentially preventing misbehaviors and failures. However, enforcers might be faulty themselves, applying the wrong actions or missing to apply the right actions.To address this problem, this paper presents Test4Enforcers, an approach to automatically test software enforces. Test4Enforcers relies on an enforcement model describing the strategy that shall be applied at runtime to correct misbehaviors. Test4Enforcers first uses the enforcement model to derive a specification of the test cases that shall be executed to validate any software enforcer implemented from the given model. Then, it automatically turns the test specification into a set of concrete test cases that can be executed against apps augmented with the enforcers.We evaluated Test4Enforces with a set of 3,135 faults injected in the enforcers derived from 13 enforcement models. Results show that Test4Enforcers can automatically reveal 64% of the faults, while existing approaches relying on crash detection can only reveal 6% of the faults. Test4Enforcers is also practical since testing an enforcer required 9 min, in the worst case.

Variable angle of insulated shotcrete under different loading rates and temperature and humidity cycles- shear test and analysis.

The new thermal insulating shotcrete is of great significance for the management of thermal damage in deep mines, and its own strength has a greater impact on the roadway insulation and safe production, so it is very necessary to study the shear strength of the new thermal insulating shotcrete under the influence of the deep hot and humid environment and the stress of mining. For the heat-insulating shotcrete, firstly, we carried out the concrete variable angle shear test under different loading rates, which concluded that the shear rate and peak shear stress showed a trend of increasing and then decreasing; as the angle increases, the different rates have a greater impact on the peak shear stress of the specimen. Secondly, the concrete variable angle shear test was carried out under the temperature and humidity cycle, which revealed that the shear strength of thermal insulated shotcrete increased firstly and then decreased with the increase of temperature at the same number of cycles. Finally, the empirical equations between the cohesive force c, the angle of internal friction ϕ and the number of warm and wet cycles n and the temperature of warm and wet cycles T are fitted with the MATLAB software respectively, and the research results provide technical references for the management of geothermal temperature in deep well projects.

Finite Element of Composite Reinforced Concrete Slender Columns Subjected to Eccentric Loads

The relationship between reinforced concrete column tests and finite element behavior is crucial for understanding and optimizing the structural performance of these elements. Concrete columns are integral components in buildings and infrastructure, and testing them under various conditions provides valuable data on their strength, stiffness, and failure mechanisms. Finite element analysis, on the other hand, is a powerful numerical method used to simulate the complex behavior of structures under different loads. By correlating experimental results from concrete column tests with finite element models, engineers can validate and refine their simulations, ensuring that the computational models accurately represent the physical reality. This iterative process of testing and analysis allows for the development of more reliable and efficient design methodologies, leading to improved structural performance and safety in construction projects. The synergy between experimental testing and finite element behavior not only enhances our understanding of structural dynamics but also contributes to the advancement of innovative and resilient construction practices. The results shows a good coincidence between the experimental and theoretical results.

Influence of fine aggregate types for the achievement of concrete quality

Fine aggregates in the form of sand are granulated materials, which generally measure between 0.0625 to 2 millimeters. Sand as a fine aggregate mixed with cement and water becomes a concrete mixture that has a role in the strength of construction. This study aims to determine how much influence the fine aggregates or sand of four different mining sites have on the compressive strength of concrete. The method used is an experiment, based on the results of laboratory tests of compressive strength tests at the age of concrete 7, 14 and 28 days for fc’25 or 25 MPa quality concrete with a mix of designs for fine aggregates from Leles sand, Kuyamut sand, Cikamiri sand, and Cilopang sand, Garut Regency West Java Province Indonesia. The aggregates tested include moisture content, sludge content, organic content, dry saturation, waand ter absorption affects the quality of concrete and improves quality strength with the same treatment for laboratory testing. The results of the analysis with 28 days of concrete compressive strength testing obtained the achievement of the highest concrete strength, namely with Cilopang sand 27 MPa, allowed by Kuyamut sand 26 Mpa, Leles sand 25 MPa and Cikamiri sand 23 MPa. Based on the results of concrete strength testing for up to 28 days, there are three sources of fine aggregates that can reach a minimum of fc’ 25, and there is one sand source that has a compressive strength value of concrete.

To study the mechanical and durability characteristics of concrete utilizing waste foundry sand

Currently, the availability of high-quality natural river sand is scarce, requiring transportation over long distances, and its rapid depletion is a significant concern. In this project, the focus lies on assessing the behavior of concrete by partially replacing natural sand with waste foundry sand. The experimental investigation primarily examines the mechanical and durability, split tensile strength, Ultrasonic Pulse Velocity Test, flexural strength, and permeability of concrete. This evaluation involves replacing natural river sand with varying percentages (0%, 10%, 20%, 30%, 40%) of waste foundry sand by weight. Tests are conducted on cubes and beams to analyze the mechanical properties and durability characteristics of concrete with waste foundry sand compared to concrete with natural sand as fine aggregate. The study includes assessments of splitting tensile strength and flexural strength at different ages (7, 28, 56, and 90 days). Results indicate a decrease in workability as the percentage of waste foundry sand in the mix increases.

Nodes of Experimental Installations for Testing Concrete for Creep

Installations of the mid-twentieth century for testing concrete for creep, as a rule, have significant wear and are not intended for testing new concrete. To carry out testing of modern highstrength concrete, their modernization and retrofitting is required. Due to the lack of standard technical solutions, design and survey work is required in preparation for testing. The purpose of the presented study was to study the nodes and elements of spring installations for determining the creep of concrete and to establish the possibility of their use under increased loads, to modernize installations for the possibility of testing samples of various lengths without complete disassembly, to ensure safety during such tests. To determine the strength and stiffness parameters of the springs, it was necessary to conduct two-stage tests with the development of special equipment. Also, according to the results of the evaluation of the hinge assemblies for axial load transfer to the sample, their replacement with a change in design solutions was required. According to the results of experimental studies, individual springs and thrust hinge elements were fragilely destroyed, in connection with which a hinge assembly of a new design was developed, changes have been made to the design of the installation to ensure the physical protection of maintenance personnel, a modular system of steel spacers with protection against horizontal movement has been developed, which makes it possible to test samples of different lengths on existing installations without changing the configuration of the installations themselves. An important result of the work is the proposed system of double experimental control, when first a random test of individual elements is carried out to assess the possible level of loads on the equipment, then a continuous control of the already assembled test installations is carried out for large loads relative to the planned experiment. Only in this case it is possible to simultaneously ensure high reliability of the results obtained during testing, reliability and durability of the equipment. Moreover, it is impossible to carry out such work only numerically without testing, as practice has shown.

Incorporating Solid Waste Particles into Concrete Design to Enhance Drainage Infrastructure

The inadequate drainage structure can cause water to accumulate on the surface of the pavement, leading to degradation and reduced lifespan of the concrete structure. This study focuses on the incorporation of solid waste particles into the concrete mix to enhance the drainage structure and other concrete structures. Solid waste particles (SWP) are added to the concrete mix to improve the strength and absorption of the concrete, thus increasing the drainage efficiency. This is an economically effective solution since solid waste particles are common and easily accessible. The study investigates the effect of different percentages of solid waste particles (0%, 5%, 10%, and 15%) on the mechanical properties of the concrete mix and its permeability. Compressive strength tests were used to determine the mechanical parameters of the concrete mixtures and water absorption test to describe the porosity and moisture sensitivity of concrete.

Investigation on Mechanical Properties of Self-Consolidating Concrete containing Slag Aggregate

This paper presents the investigation results on self-consolidating concrete (SCC) produced with slag aggregate (SA). The characteristics of materials, sieve distribution of aggregates, design of self-consolidating concrete mixture and its fresh concrete properties test such as slump flow test, V-funnel, U-funnel and L-box are analyzed. The mechanical properties of SCC are with two different grades slag aggregate is tested for compressive strength (f’c), split tensile strength (fst), young’s modulus (Ec) and durability test. The investigation result on concrete mechanical properties shows that mix with larger aggregate exhibits higher values than the companion mix with smaller aggregate. Although it exhibits fairly optimum strength characteristics with slag aggregate substitution but the higher percentage of replacement affects the durability properties. This study leaves a positive way of application of slag aggregate in concrete.

The 365 km tunnels assessment along ASPI Motorways Network – Key findings addressing risk analysis procedures and structural conditions evaluation and strategy of interventions

An extraordinary assessment plan, performed on 365 km of motorway tunnels, has been carried out in Italy since 2020 starting with detailed inspections and testing. Hundreds of laser scanning kilometres and ground-penetrating radargrams, thousands of concrete compressive strength tests, endoscope inspections and flat-jack tests have been performed so far. Tens of thousands structural defects were detected and several square meters of temporary safety measures installed as well. This allowed to acquire a significant amount of knowledges about the current condition of the asset. According to the process defined by the new Italian Regulations, the dataset analysis provides an insight into the condition of the asset, guiding the entire maintenance process. The visual and detailed inspections frequency is driven by the simplified risk analysis outcome and further safety evaluation are designed based on multidisciplinary criticality. A comprehensive approach, based on in-depth knowledge of the characteristics of the existing tunnel, has been engineered for structural risk, with a focus on tunnel “history” (excavation stages and techniques, construction materials, etc.), design and dimensioning approaches (e.g. Kommerel’s graphical method), identified as standard methods for the tunnel construction period from literature review. Additional analyses are carried out for likely local structural failure modes of tunnel lining (punching and flexural strength of residual concrete layers, spalling hazard of concrete thickness anomalies due to temperature variations). When re-lining is needed, the design of a new shell aimed to ensure at least the same structural performance of the original one is addressed, including seismic loads that were neglected in the original design. The tunnel assessment, from inspections to re-lining works passing through risk analysis, is an on-going process open to be improved in the upcoming years within a wider asset management strategy.

Number of concrete strength tests using the elastic rebound method

The article discusses the determination of the required number of experiments when determining the compressive strength of concrete using the elastic rebound method. It is shown that it is not correct to accept a deterministic value for the minimum number of experiments for all grades (classes of concrete). This value depends on the average strength of concrete and the instrument error of the device used. For a given coefficient of variation, with increasing concrete strength, the required number of experiments increases. For the maximum permissible coefficient of variation of concrete strength of 13.5%, calculated dependences of the minimum number of experiments on the average strength of concrete were obtained for the minimum and maximum instrumental errors of the sclerometers used, determined by analyzing the passport data used in Russian organizations involved in the inspection of buildings and structures. The proposed method, which relates the strength of the material of the structure under study and the instrumental error of the device used, can be extended to other methods of determining strength by non-destructive methods and can be the basis of the technical specifications for the creation of devices for non-destructive testing of concrete.

Experimental study of precast concrete walls using bamboo as alternative reinforcement

The public's demand for simple, livable houses means that material studies to support this continue to be carried out today, starting from using natural materials such as bamboo as precast concrete walls. This study aims to conduct an experimental study using bamboo rope from the Gigantochloa Apus variety as an alternative reinforcement for precast concrete walls. Research was carried out on 12 precast concrete wall test specimens, and the flexural properties, flexural strength, and crack patterns were formulated when subjected to a quasi-static load concentrated in the middle of the span. The concrete slab measures 600800 mm with a 50 and 75 mm thickness. The three configurations of bamboo bones used include (1) Gedhek-type woven bamboo slats, (2) bamboo slat type, and (3) Sasak-type woven bamboo slats. The research results show that Sasak-type woven bamboo slat reinforcement is the most effective alternative reinforcement. The behavior of the test specimen shows a ductile failure pattern similar to conventional reinforced concrete. The maximum moment capacity achieved is 1.5 to 2.2 times greater than the theoretical nominal moment capacity. Meanwhile, the behavior of test specimens with conventional plate-type woven bamboo slat reinforcement showed sudden and brittle failure due to slippage at the bond between the bamboo reinforcement and concrete. The average maximum moment from the test results is 60% of the theoretical nominal moment. The results of this research recommend that woven bamboo slats of the conventional plate reinforcement type are less effective as alternative reinforcement if they are not given special treatment to increase their adhesion to concrete. Gedhek-type woven bamboo slats are not effective as alternative reinforcement because they cause separation of the top and bottom parts of the woven concrete, thereby reducing the integrity of the cross-section and causing the cross-sectional capacity to be relatively small.

Compressive Strength Prediction Model of High Strength Concrete by Destructive and Nondestructive Technique

Concrete’s compressive strength can be tested in a laboratory before construction begins. Since concrete is a natural material and cannot be destroyed, it is not possible to determine its compressive strength through destructive testing. Rebound hammers are typically used in the field to evaluate the structural elements’ ability to withstand hardened concrete. As part of the current study, a comparison was made between concrete’s compressive strength measured by destructive testing and its surface hardness measured by rebound hammering. Tests were conducted on laboratory-made concrete cubes in this study to determine destructive and non-destructive behavior. Minitab software was used for regression analysis. Schmidt rebound hammer tests, a type of nondestructive testing (NDT), were shown to have very strong relationships with concrete destructive compression tests. Schmidt rebound hammers are commonly used to measure the surface hardness of concrete, since the hammer rebound number and concrete strength are theoretically correlated. Utilising a Schmidt hammer, it was applied. Standard concrete cubes with crushing strengths between 20 and 30 MPa were created using various mix proportions. Using regression analysis, destructive and non-destructive values are correlated. The linear regression equation is well suited for obtaining the compressive strength using rebound value by using linear regression equation.

A Green Infrastructure SDGS Num 11: Approach Planning Design Model Reliability of Permeability and Concrete Quality Rural Roads P3MD Program in Wonogiri

Design planning permeability and quality of rural concrete road construction work in the Program Pembangunan dan Pemberdayaan Masyarakat Desa (P3MD) of the Ministry of Villages, Development of Disadvantaged Regions and Transmigration in Wonogiri, which is environmentally friendly in accordance with the sustainable development goals of SDGs Number.11 Villages "Sustainable Cities and Community", is the urgency of global action to reduce the impact of climate change and overcome challenges in developing a village road infrastructure model that is sustainable and leads to Green Infrastructure. Testing the permeability of village road construction materials using a rational classification method based on the Unified Soil Classification System, ASTM and International Nomenclature Darcy’s Law by calculating the input discharge of rainwater seeping into the soil through the pores of road construction using a rational method, testing the compressive strength of concrete roads using Rebound Hammer / Concrete Hammer Test method, SNI Standard 03-4430-1997. The results of the input volume of rainwater seeping into the ground through the pores (run off) of rural roads construction in Wonogiri one year is 724,866 m3. The average compressive strength of concrete roads from the hammer test results for concrete road test is 290 kg/cm2> K-225 kg/cm2, than the desired construction, namely; standard deviation; (S=1.75), coefficient of variation (Kv= 7.35%), indicating that the data taken has a sufficient level of accuracy, while the uniform data is quite representative of the road section studied.