Assessment Of Concrete Quality Research Articles

Prioritization of the Requirements Formulated in the European Standard EN 206 in Assessment of Concrete Quality - Multicriteria Analysis Using the AHP Method

Prioritization of the Requirements Formulated in the European Standard EN 206 in Assessment of Concrete Quality - Multicriteria Analysis Using the AHP Method

Risk analysis in quality assessment of ready-mixed concrete using fuzzy logic

The decision to include the considered batch of concrete in the designed class depends on the satisfaction of the conditions imposed on the strength of each individual result and the average value. The concrete conformity criteria are formulated in EN 206+A1:2016. When considering risk in concrete quality assessment, it can be assumed that there are three levels of result: low, medium, and high risk in quality assessment. Using logical operations on fuzzy sets, inference rules can be constructed to establish relationships between different variables. The paper presents an analysis of the risk of produced concrete carried out for two input parameters. Parameters on the average compressive strength of concrete and online defects obtained during compliance checks. Defects are identified by the probability of their occurrence. The third parameter introduced relates to the consequences of the occurrence of events identified with the obtained defectiveness after the compliance check of the compressive strength of the concrete produced. When verifying the compressive strength of concrete based on a sample size of n = 3, with the result obtained of a mean value of 28 MPa and a defect before and after conformity control defined at the medium defectiveness, the risk regarding the correct assessment of the quality of the produced concrete is medium.

Quality Assessment of Concrete produced with Marble dust as Partial Replacement of Cement using Ultrasonic Pulse Velocity Test

Cement concrete is one of the most frequently used materials in the construction industry. Constant studies are being carried out to find some alternative material to save natural resources and instead make use of industrial byproducts/waste material which is otherwise polluting the environment. Marble dust which is an industrial waste obtained from sawing, shaping, cutting and polishing of different marbles, is a big environmental hazard. Around 6.8 million tonnes of marble dust is currently being dumped annually in Rajasthan, Gujarat and Madhya Pradesh in India. Although past studies have already investigated the use of this material as a substitute for fine aggregates, since its distribution of particle size is nearer to that of cement, it could be more appropriate for partial replacement of cement in concrete. Cement concrete cubes of size 150 mm were cast as control specimens for two different grades of concrete (M25 Grade and M30 Grade). Effect of marble dust on compressive strength of concrete with varying %age of marble dust as partial replacement of cement is investigated in this study. Marble dust is used as 0, 5, 10, 15 and 20 percent partial substitute of cement by weight in concrete mixes. The compressive strength of concrete mixes is studied at age of 28 days and maximum value of compressive strength is observed at 10% partial replacement of marble dust with cement for both grades of concrete. The quality of concrete so produced is also assessed by using Ultrasonic Pulse Velocity (USPV) method. The ultrasonic pulse velocity is 3850, 4100, 4350 and 3710 m/s for M25 grade concrete and 3870, 4120, 4360 and 3700 m/s for M30 grade concrete for 0%, 5% and 15 % partial replacement of marble dust with cement. As per IS :13311(Part 1):1992 these values of pulse velocities represents good quality of concrete and also justified the use of marble dust in concrete up to 15 percent for both grades of concrete (M25 and M30).

Limit values of accelerated carbonation resistance to meet EC2 durability requirements

Although accelerated carbonation resistance has been extensively tested, there are no recommendations for the application of test results in codes of practice. The main objective of this study was to determine the limit values of accelerated carbonation resistance to satisfy the required service life of reinforced concrete structures with concrete covers as prescribed in EN 1992-1-1. The service life of 50 years was considered, as well as all carbonation exposure classes (from XC1 to XC4). A full probabilistic analysis was conducted using the fib-Bulletin 34 carbonation prediction model. Using the limit state function and a defined reliability index, the upper limits of the inverse effective carbonation resistance (R-1 ACC) for all exposure classes and in a function of concrete cover depth were determined. The determined values of R-1 ACC presented in this study represent the upper limit of the average value, as well as the maximum deviation of one sample in relation to this average value. Thus, a simple assessment of concrete quality is allowed in terms of carbonation resistance based on the accelerated carbonation depth measurements.

Interlaboratory Comparative Tests in Ready-Mixed Concrete Quality Assessment.

Proper quality assessment of ready-mixed concrete, which is currently the principal material for construction, land engineering and architecture, has an impact on the optimisation and verification of correct functioning of individual stages of the production process. According to the European Standard EN 206 “Concrete–Specification, performance, production and conformity”, obligatory conformity control of concrete is carried out by the producer during its production. In order to verify the quality of concrete, investors generally commission independent laboratory units to perform quality assessment of both concrete mix and hardened concrete, which guarantees a high quality of construction works. One of the essential tools for ensuring the quality of test results is the participation of laboratories in the so-called proficiency testing (PT) or inter-laboratory comparisons (ILC). Participation in PT/ILC programmes is, on the one hand, a tool for demonstrating the laboratory’s performance, on the other hand an aid for maintaining the quality of available concrete tests and validating test methods. Positive evaluation is a confirmation of the laboratory’s capability for performing the tests. The paper presents the results of laboratory proficiency tests carried out by means of inter-laboratory comparisons, as shown in the example of quality assessment of ready-mixed concrete for nine participating laboratories. The tests were performed for concrete of the following parameters: strength class C30/37, consistency S3, frost resistance degree F150, and water resistance degree W8. This involved determining consistencies, air content and density of the concrete mix, and compressive strength of hardened concrete. For the evaluation of laboratory performance results, z-score, ζ-score and En-score were applied. The innovation of the proposed study lies in employing both classical and iterative robust statistical methods. In comparison with classical statistical methods, robust methods ensure a smaller impact of outliers and other anomalies on the measurement results. Following the analyses, clear differences were found between the types of detected discrepancy of test results, which occurred due to the nature of individual parameters. For two laboratories, two scores revealed unsatisfactory results for concrete mix consistency. The main reasons can be pouring into the cone-shaped form a concrete mixture that is too dry, or incorrect use of a measuring tool also creating a possibility that the obtained value can be wrongly recorded. Other possible reasons are discussed in the paper. Participation in inter-laboratory comparison programmes is undoubtedly a way to verify and raise the quality of tests performed for concrete mix and hardened concrete, whereas individual analysis of the results allows the laboratory quality system to be improved.

EVALUATION OF SEKOLAH ISLAM TERPADU (SIT) ALIYA BOGOR BUILDING STRUCTURE SYSTEM BASED ON THE REQUIREMENTS OF SNI 2847:2019

<p class="ListParagraph1">Sekolah Islam Terpadu (SIT) Aliya Bogor is located in west Bogor district, Bogor city, West Java, was founded in 200, thus the standards used by planning consultant in building planning using old standard, where these standards have been updated with current standard, namely SNI 2847:2019. The evaluation carried out in this study based on requirements SNI 2847:2019 knowing the outcome of building that was said to be safe used help software ETABS) and SpColumn. Length of building of Umar Bin Khatab A and B are 18,60 meter;23,65 meter.Building area of building Umar Bin Khatab A and B are 541,26 m<sup>2</sup>; 865,59 m<sup>2</sup>. Concrete quality assessment (fc’) that came from the test of hammer test column elements, beam elements, and plate elements as big 23,74 Mpa;26,59 Mpa;26,59 Mpa. After analysis some of to experience overstrength. The original column dimension In Building of Umar Bin Khatab A was K25x25 with shear reinforcement is Ø16-150 enlarge to K40x40 with shear reinforcement is Ø39-150 and beam dimension 20x40 enlarge to 35x55. On the building of Umar Bin Khatab B was K25x25 with shear reinforcement Ø16-150 enlarge to K40x40 with shear reinforcement Ø25-150, with the original beam dimension 20x40 enlarge to 30x55. The cost budget in the building of Umar Bin Khatab A is Rp 74.158.600,00 and in building of Umar Bin Khatab B is Rp 61.084.600,00.</p>

Correlation of Rapid Electrochemical and Traditional Performance-Based Test Results for Assessing the Degree of Sulfate Resistance in Concrete

The aim of this study was to develop and propose classification criteria for practical assessment of concrete quality with a rapid sulfate resistance test. The rapid electrochemical sulfate resistance test based on ASTM C1202 has various advantages over the traditional performance test methods, such as short testing time, simple procedure, clear interpretation, and reasonable results. The proposed criteria were experimentally evaluated in both a series of laboratory test specimens and in specimens collected from various construction sites. The experimental results of the rapid electrochemical test and the traditional length change according to ASTM C1012 were correlated to develop performance specifications regarding ion sulfate penetration. The performance specifications proposed on the basis of this study have six levels of ion penetrability. The proposed performance specifications with rapid electrochemical test method are expected to lead to practical applications in the cement and concrete industries.

Study of Quality Parameters of Long-Term Strength of Cement Composites

The currently widespread assessment of concrete quality, including reliability, by traditional mechanical characteristics is ineffective, since these state parameters do not take into account changes in the strength and deformation properties of concrete under the influence of temporary processes of microcracking during loading when diagnosing structural materials. Modern development of fracture mechanics has made it possible to establish scientific principles for evaluating materials and testing methods and to propose together force, strain, energy and acoustic criteria for crack resistance that determine the actual limit States of their structure in terms of strength and deformability and thus allow predicting the performance of the material under load. This paper presents the results of experimental evaluation of mechanical failure criteria and regularities of changes in acoustic emission parameters from the loading intensity during non-equilibrium mechanical tests for three-point bending of experimental samples with an initial incision depth of 13 mm. Analysis of the influence of the concentration and the introduction of SP-3 on regularities of changes in the coefficients of increase of controlled criteria of crack resistance in time relative to 28-day age quite clearly suggests, first, that the change of parameters of criteria of crack resistance in time has a wavelike nature, and the change in strength under axial compression, and, secondly, about, that the modified structures of cement stone samples relative to the control composition generally give significantly better indicators not only of the growth coefficients of the compared quality criteria, but also of the absolute values of the criteria for crack resistance up to 18 years of age.

A Proposal of a Method for Ready-Mixed Concrete Quality Assessment Based on Statistical-Fuzzy Approach.

Control of technical parameters obtained by ready-mixed concrete may be carried out at different stages of the development of concrete properties and by different participants involved in the construction investment process. According to the European Standard EN 206 “Concrete–Specification, performance, production and conformity”, mandatory control of concrete conformity is conducted by the producer during production. As shown by the subject literature, statistical criteria set out in the standard, including the method for concrete quality assessment based on the concept of concrete family, continue to evoke discussions and raise doubts. This justifies seeking alternative methods for concrete quality assessment. This paper presents a novel approach to quality control and classification of concrete based on combining statistical and fuzzy theories as a means of representation of two types of uncertainty: random uncertainty and information uncertainty. In concrete production, a typical situation when fuzzy uncertainty can be taken into consideration is the conformity control of concrete compressive strength, which is conducted to confirm the declared concrete class. The proposed procedure for quality assessment of a concrete batch is based on defining the membership function for the considered concrete classes and establishing the degree of belonging to the considered concrete class. It was found that concrete classification set out by the standard includes too many concrete classes of overlapping probability density distributions, and the proposed solution was to limit the scope of compressive strength to every second class so as to ensure the efficacy of conformity assessment conducted for concrete classes and concrete families. The proposed procedures can lead to two types of decisions: non-fuzzy (crisp) or fuzzy, which point out to possible solutions and their corresponding preferences. The suggested procedure for quality assessment allows to classify a concrete batch in a fuzzy way with the degree of certainty less than or equal to 1. The results obtained confirm the possibility of employing the proposed method for quality assessment in the production process of ready-mixed concrete.

A Novel Approach for Automatic Detection of Concrete Surface Voids Using Image Texture Analysis and History-Based Adaptive Differential Evolution Optimized Support Vector Machine

To inspect the quality of concrete structures, surface voids or bugholes existing on a concrete surface after the casting process needs to be detected. To improve the productivity of the inspection work, this study develops a hybrid intelligence approach that combines image texture analysis, machine learning, and metaheuristic optimization. Image texture computations employ the Gabor filter and gray-level run lengths to characterize the condition of a concrete surface. Based on features of image texture, Support Vector Machines (SVM) establish a decision boundary that separates collected image samples into two categories of no surface void (negative class) and surface void (positive class). Furthermore, to assist the SVM model training phase, the state-of-the-art history-based adaptive differential evolution with linear population size reduction (L-SHADE) is utilized. The hybrid intelligence approach, named as L-SHADE-SVM-SVD, has been developed and complied in Visual C#.NET framework. Experiments with 1000 image samples show that the L-SHADE-SVM-SVD can obtain a high prediction accuracy of roughly 93%. Therefore, the newly developed model can be a promising alternative for construction inspectors in concrete quality assessment.

Application of a Sclerometer to the Preliminary Assessment of Concrete Quality in Structures After Fire

Abstract The paper presents a description and results of a study focused on the applicability of the sclerometric method to the preliminary assessment of concrete quality in structures after fire. Due to the high thermal inertia, concrete has non-uniform properties in the heated element cross-section. The greatest reduction of concrete compressive strength occurs on the heated surface. When assessing a structure after a fire, it is particularly important to determine the thickness of the damaged external concrete layer. Reinforced concrete beams exposed to high temperature on one side (a one-way heat transfer in the cross-section) for 0 (unheated element), 60, 120, 180 and 240 minutes were examined. A significant decrease of the rebound number on the elements heated surface was observed, depending on the heating duration. The obtained values of the relative rebound number reduction were comparable to the values of relative compressive strength decrease (determined on the basis of temperature) of concrete situated 15 mm from the heated surface.

The assessment of concrete quality by ultrasonic pulse velocity

In the present study, the uniformity and potential internal defects of concrete elements in situ were assessed by using Ultrasonic Pulse Velocity (UPV) testing method according to TCVN 9357:2012. Thirteen cross beams with dimension of 4.8 x 1.5 x 1.5 m3 were selected to measure the pulse velocity. Three cross beams were used to check potential internal defects in concrete and 10 cross beams were used to assess the uniformity of concrete in the elements. The results showed that there is no potential internal defect with size over 100 mm in three tested beams and concrete quality of all tested beams is good with the coefficient of variation (CV) of ultrasonic pulse velocity results of all tested points is lower than 2%.
 Keywords: concrete; homogeneity; internal defects; ultrasonic pulse velocity.

Influence of calcium carbonate whisker and polyvinyl alcohol- steel hybrid fiber on ultrasonic velocity and resonant frequency of cementitious composites

Inclusion of hybrid fiber in cementitious composites could restrict the growth of cracks at different stages and improve the mechanical properties of concrete, and adding calcium carbonate (CaCO3) whisker would further improve the mechanical properties of cementitious composites. Nevertheless, no attention has been paid to the effects of steel- polyvinyl alcohol (PVA) hybrid fiber and whisker on ultrasonic pulse velocity (UPV) and resonant frequency (RF) of hybrid fiber reinforced cementitious composites (HyFRCC), although they have been used widely in quality assessment of concrete. In this research, 114 specimens have been used to explore the influences of steel-PVA hybrid fiber and whisker on the UPV, RF parameters and the mechanical properties. The results of this research present that there may exists “fiber gradation” in HyFRCC, because there is always a best fiber combination to reach the greatest compactness and highest non-destructive testing results. In addition, the partial substitution of PVA fiber by whisker decreased UPV and RF and increased density loss rate and compressive strength except for one mixture. Therefore, UPV, RF can reflect the effect of whisker on the inner structure and detect the variation, and have potential use to evaluate HyFRCC in engineering applications.

Prediction of concrete compressive strength using non-destructive test results

Concrete which is a composite material is one of the most important construction materials. Compressive strength is a commonly used parameter for the assessment of concrete quality. Accurate prediction of concrete compressive strength is an important issue. In this study, we utilized an experimental procedure for the assessment of concrete quality. Firstly, the concrete mix was prepared according to C 20 type concrete, and slump of fresh concrete was about 20 cm. After the placement of fresh concrete to formworks, compaction was achieved using a vibrating screed. After 28 day period, a total of 100 core samples having 75 mm diameter were extracted. On the core samples pulse velocity determination tests and compressive strength tests were performed. Besides, Windsor probe penetration tests and Schmidt hammer tests were also performed. After setting up the data set, twelve artificial intelligence (AI) models compared for predicting the concrete compressive strength. These models can be divided into three categories (i) Functions (i.e., Linear Regression, Simple Linear Regression, Multilayer Perceptron, Support Vector Regression), (ii) Lazy-Learning Algorithms (i.e., IBk Linear NN Search, KStar, Locally Weighted Learning) (iii) Tree-Based Learning Algorithms (i.e., Decision Stump, Model Trees Regression, Random Forest, Random Tree, Reduced Error Pruning Tree). Four evaluation processes, four validation implements (i.e., 10-fold cross validation, 5-fold cross validation, 10% split sample validation & 20% split sample validation) are used to examine the performance of predictive models. This study shows that machine learning regression techniques are promising tools for predicting compressive strength of concrete.

Concrete quality assessment before building structures submitting to environmental exposure conditions

DOI: 10.7764/RDLC.16.3.374 Abstract A study on concrete quality assessment before building structures submitting to environmental exposure conditions was carried out. It was necessary to determine the ultrasonic velocity pulse, compressive strength and percentage of effective capillary porosity values in concretes probes of water/cement ratio 0.4, 0.5 and 0.6.The results allowed to demonstrate how from relationship between compressive strength and percentage of effective capillary porosity, as well as, from relationship between capillary coefficient absorption and percentage of effective capillary porosity, durability requirements were obtained. Durability requirements were: Critical value of percentage of effective capillary porosity from which the concrete permeability increased. Critical value of percentage of effective capillary porosity from which, compressive strength decreased. Ultrasonic pulse velocity and compressive strength tests by itself were not enough to concrete quality assessment. Results using the visual observation were confirmed, in the reinforced concrete probes exposed to corrosivity categories of the atmospheres very high (C5) and extreme (CX) in a tropical coastal climates during three years, as well as by scanning electron microscopy tests in small samples of hardened cement paste for the three water/cement ratios.

Assessment of Concrete Quality of Load-Bearing Structure of the Bridge across Otava River No. 121-006 near Zvikov after Fifty Years of Operation in Severe Environmental Conditions

This paper is introducing results of diagnostic survey of bridge no. 121-006 across Otava river near Zvikov [1], focusing on assessment of quality of concrete mix used for load-bearing structure of the bridge after more than 50 years of operation and assessment of reconstruction works (monolithic assembly of central joints of main fields) executed in 1994 [2]. Visual inspection of monolithic assembly joints, comparison of depth of concrete carbonation and thickness of top layer of reinforcement concrete and concrete compression strength are presented in this paper.

Delamination and concrete quality assessment of concrete bridge decks using a fully autonomous RABIT platform

One of the main causes of a limited use of nondestructive evaluation (NDE) technologies in bridge deck assessment is the speed of data collection and analysis. The paper describes development and implementation of the RABIT (Robotics Assisted Bridge Inspection Tool) for data collection using multiple NDE technologies. The system is designed to characterize three most common deterioration types in concrete bridge decks: rebar corrosion, delamination, and concrete degradation. It implements four NDE technologies: electrical resistivity (ER), impact echo (IE), ground-penetrating radar (GPR), and ultrasonic surface waves (USW) method. The technologies are used in a complementary way to enhance the interpretation. In addition, the system utilizes advanced vision to complement traditional visual inspection. Finally, the RABIT collects data at a significantly higher speed than it is done using traditional NDE equipment. The robotic system is complemented by an advanced data interpretation. The associated platform for the enhanced interpretation of condition assessment in concrete bridge decks utilizes data integration, fusion, and deterioration and defect visualization. This paper concentrates on the validation and field implementation of two NDE technologies. The first one is IE used in the delamination detection and characterization, while the second one is the USW method used in the assessment of concrete quality. The validation of performance of the two methods was conducted on a 9 m long and 3.6 m wide fabricated bridge structure with numerous artificial defects embedded in the deck

Assessment of Concrete Quality in Libya

Abstract The quality of concrete used in current and past 20 construction projects were examined based mainly on the concrete compressive strength achieved. The projects are different in nature and are at various levels of completeness. In Libya, concrete compressive strength was usually obtained from test results of a 150 mm standard cube mold. Data collected from all 20 projects showed that the 28-day concrete compressive strength follow in general Normal Distribution pattern. The study dealt with concrete quality aspects such as: quality control, strength range, data standard deviation, data scatter, and ratio of minimum strength to design strength. Site quality control for these projects ranged from very good to poor according to ACI214 criteria. The ranges (Rg) of the strength (max. strength – min. strength) divided by average strength are from 34% to 160%. Data scatter is measured as the range (Rg) divided by standard deviation (σ) and is found to be (1.82 to 11.04), indicating that the range is ±3σ. In lieu of national unified procedure, international construction companies working in Libya are free to use the assessment criteria for concrete compressive strength that suit them. Therefore, the study reveals that concrete quality assessments conducted by these construction companies usually meet their adopted (internal) standards, but sometimes fail to meet internationally known standard requirements. The assessment of concrete presented in this paper is based on ACI, British standards and proposed Libyan concrete strength assessment criteria.

Assessment of Scaling Durability of Concrete with CFBC Ash by Automatic Classification Rules

The objective of this investigation was to develop rules for automatic assessment of concrete quality by using selected artificial intelligence methods based on machine learning. The range of tested materials included concrete containing nonstandard waste material—the solid residue from coal combustion in circulating fluidized bed combustion boilers (CFBC ash) used as an additive. Performed experimental tests on the surface scaling resistance provided data for learning and verification of rules discovered by machine learning techniques. It has been found that machine learning is a tool that can be applied to classify concrete durability. The rules generated by computer programs AQ21 and WEKA by using the J48 algorithm provided a means for adequate categorization of plain concrete and concrete modified with CFBC fly ash as materials resistant or not resistant to the surface scaling.

Assessment of concrete quality using non-destructive techniques, Ghatghar project, Maharashtra, India

The Ghatghar Pumped Storage Scheme involves the construction of two roller compacted concrete dams. Cracks were observed when the 14.5m × 478 m dam across the river Pravara near Ghatghar village, Maharashtra, India was about 4.1 m high on the right side and 3.3 m high on the left side. A total of 1,206 measurements were made using seismic refraction, sonic tomography and ultrasonic testing to assess the competency of the dam, covering a volume of 5029.86 m3. The ultrasonic testing conducted on five RCC cores and an equal number of rock cores recovered from the body of the dam and site indicated a velocity of 4,050–4,250 and 3,900–4,100 m/s, respectively. The velocities obtained from the seismic refraction and tomographic survey ranged between 3,375 and 4,625 m/s and from the ultrasonic survey 3,800–4,300 m/s. The velocity range obtained from both the seismic (refraction and tomographic) and ultrasonic methods indicates good to excellent quality concrete and the results show the visible cracks have not affected the integrity of the dam.