Concrete Quality Research Articles

Mechanical and microstructural properties of pavement quality concrete using both Class-F fly-ash and copper slag

This research deals with the improvement in the mechanical properties of pavement quality concrete (PQC) when mixed with Class-F Fly-Ash (FA) and Copper Slag (CS) as replacements for ordinary Portland cement (OPC) and river sand (RS), respectively. Forty-eight different PQC mixes of M40 and M50 grades were prepared, in which RS is replaced by CS to the extent of 100%, and OPC is replaced by FA to the extent of 30%, with each replacement done at a certain increment. The combined effects of CS and FA on fresh and hardened concrete properties such as workability, density, water absorption, volume of voids, cube compressive strength, split tensile strength, flexural strength, cylinder compressive strength and ultrasonic pulse velocity (UPV) are experimentally investigated. All mixes containing up to 20% FA and up to 100% CS replacements showed increased strength compared with that of the control mix. The PQC mix containing 20% FA and 60% CS resulted in superior strength properties at a 90-day curing period. However, PQC mixes with 30% FA showed a decrease in strength properties with respect to the control mix. X-ray diffraction (XRD) and scanning electron microscope (SEM) studies were employed for the characterisation of selected PQC samples. Furthermore, multiple linear regression equations were established to predict all the strength parameters. The PQC mixes made with FA and CS provide superior strength, reduce waste disposal problems and preserve natural resources for future generations, making such developed mixes sustainable.

A Review of Effect of Mineral Admixtures on Appearance Quality of Fair-Faced Concrete and Techniques for Their Measurement

The appearance of fair-faced concrete is crucial, and it can be enhanced by incorporating an appropriate amount of mineral admixture. Different mineral admixtures have varying effects on the appearance quality of fair-faced concrete. For instance, the addition of fly ash helps control color differences and bubble formation on the concrete surface, while slag powder effectively controls its color and finish. In this review, the impact of using various mineral admixtures, such as silica fume, rice husk ash, limestone powder, and seashell powder, in fair-faced concrete on its appearance quality is examined. The effective combination of mineral admixtures made from industrial by-products or solid waste with fair-faced concrete can pave the way for new directions in the green and sustainable development of construction materials. This review also discusses the difficulties in objectively measuring the appearance quality of concrete and the various methods for the acquisition and evaluation of appearance images. New techniques for acquiring and evaluating information about concrete surfaces have been developed with advancements in image acquisition and processing technology. These techniques complement traditional manual inspection methods. The 3D Alicona system is advantageous for identifying air bubbles on concrete surfaces, the atomic-force microscope detects surface roughness, and the Orbital large-format scanner is ideal for use in large-scale engineering applications. Also, evaluation methods for different image processing software are presented in this article. This information offers a useful reference for future research and practical application.

Intelligent Analysis of Hydraulic Concrete Vibration Time Based on Convolutional Neural Network

The vibrating of concrete is one of the most important procedures that directly determines the quality of construction projects. The concrete vibration quality in field construction is mainly judged by the experience of workers, lacking quantitative indicators, and necessary supervision. However, the lack of research about concrete vibration quality led to these problems are still existing. There are some methods are proposed that are too difficult, or too expensive to use in field construction. Combined with the pouring project of Jianquan Pumped Storage Power Station in Yunyang, China, this research developed an intelligent detection system for concrete vibration time. The system took the convolutional neural network as the basic framework, and divided the concrete vibration process into three different states: vibrating, not vibrating, and no vibration tube, realized the concrete vibration time through the analysis of concrete vibration video data. The detection of concrete vibration process video with multiple stages in the actual project shows that the detection error of the system for each state is kept within 1 s, the accuracy is high, which can meet the quality management requirements of the construction process. The system can be quickly deployed to the construction site by using mobile phones, cameras, and other common equipment. It has the advantages of simple frame structure, low hardware requirements, and accurate detection results. In addition, the current system training process is only for the concrete pouring process of Jianquan Power Station, and the training sample can be further expanded in the future to enhance the applicability and accuracy of the system in other engineering applications in order to play a better role.

Design and analysis of timber-concrete-based civil structures and its applications: A brief review

Abstract Builders, designers, and the research community are becoming interested in incorporating timber and concrete based composite structures because they effectively integrate the structural qualities of timber and concrete. The structure’s stiffness, ductility, and load capacity are all affected by the quality of the timber connections used in construction. However, timber-concrete-based structures are limited due to a lack of design knowledge and the brittle failure behaviour of timber under shear or tensile loading. Experimental, numerical, and analytical methods have been proposed in the literature, and the key parameters influencing the performance of timber-concrete structures have been discussed. This study addresses the current challenges in designing timber-concrete connections and their failure modes and suggests simple performance-based analytical models that determine the failure mode. It looks at some of the best numerical design methods used in the past and tries to determine the best way to use timber as a possible way to use safe design principles for timber–concrete composite structures in the future.

Early Mechanical and Microstructure Evolution Characteristics of Concrete in Steam Curing Condition

In order to study the effect of steam curing on early mechanical properties of concrete, the strength, dynamic elastic modulus, and microstructure characteristics of concrete under different curing methods were tested. The results show that the early strength growth rate of steam curing concrete is obviously higher than that of standard curing. The strength development of concrete during steam curing can be divided into three stages. Stage I and stage II (0 h-30 h) are critical periods for concrete strength growth. The dynamic elastic modulus of steam-curing concrete is mainly formed in the early stage and shows a linear rapid growth characteristic. The growth rate of the dynamic elastic modulus of concrete under standard curing condition is relatively slow, but in the later curing period (30 h-48 h), the growth rate of dynamic elastic modulus of concrete is significantly higher than that of steam curing concrete. Steam curing can accelerate the production of cement hydration products which rapidly increases the early strength of concrete. Under the standard curing condition, the hydration product structure of concrete is more compact, which is conducive to the growth of dynamic elastic modulus in a later period. This study provides a theoretical reference for the application of steam curing in engineering, which is important to ensure the production efficiency and quality of concrete in engineering.

Geometric quality assessment of precast concrete (PC) elements based on 3D structural light scanning

ABSTRACT The geometric quality of precast concrete (PC) elements is critical in the construction and management of prefabricated construction. However, traditional manual inspection is time-consuming, inaccurate and costly. Therefore, an effective and low-cost non-contact inspection method is needed to support the geometric quality inspection of PC elements as a way to improve inspection efficiency and accuracy. In this study, an intuitive, effective and inexpensive geometric quality inspection method is proposed to evaluate the geometric quality of PC elements using 3D structural light scanning technology. The proposed method fits the point cloud data model of PC elements to the design model, visualizes the range of dimensional deviation of the whole element by the generated deviation chromatogram, and then evaluates the overall geometric quality of PC elements based on the local absolute deviation distance and the average deviation distance. The evaluation results classify PC elements into qualified products, partially unqualified products and severely defective products, which can be directly used to guide the treatment of unqualified products. The method is highly integrated with realistic construction and has a strong practical value. This study enriches the means of assessing the geometric quality of PC elements and shows potential for implementation in real practice.

Experimental research on pervious concrete performance with partial replacement of foundry sand nano and GGBS

Roads serve a crucial role in linking geographical areas and people around the world. Road system construction requires additional engineering expertise in the areas of material selection, weight carrying capability, duration, etc. Fortunately the majority of new roads suffer from seepage of water from the top to the bottom, which deteriorates the road's surface. We are creating and putting in pervious concrete to enable water to drain fast. Pervious concrete is a special type of high-porosity concrete utilised for concrete flatwork applications. The fine aggregate in typical pervious concrete is minimal to non-existent, and there is just enough cement paste to cover the coarse aggregate while preserving the interconnectivity of the voids. Concrete is treated with nanosilica to reduce the amount of carbonization duringproduction process. The explanation is that the concrete's microscopic flaws and UV damage to the polymer molecules are lessened by the nano-SiO2 particles. Then, GGBS (Ground Granulated Blast Furnace) is used to protect against both sulphate attack and chloride attack and to acquire strength over a longer period of time in production settings. The major goal of this concrete is to produce high-porosity concrete. This concrete allows rainwater to pass through as well as investigating the behaviour of nanosilica, GGBS and foundry sand substituted from various sources. As a result, by minimising runoff, groundwater levels could be improved. To examine the effect of nanosilica, GGBS, and foundry sand on the quality and performance of pervious concrete, compressive strength of concrete was done in the laboratory. Finding the right combination and proportion for constructing concrete with the right amount of strength while maintaining engineering performance and quality is the innovative aspect of our work. The findings of this study recommends the use of low volume pavements, slope stabilisation and pavement in residential roads, alleys and driveways.

Interlayer Aggregates Embeddedness Index and Its Characterization for Interlayer Bonding Quality of Roller-Compacted Concrete

Interlayer Aggregates Embeddedness Index and Its Characterization for Interlayer Bonding Quality of Roller-Compacted Concrete

Reducing the use of cement with marble waste for seaside concrete construction through the Graphite Carbon Particles system

This research aims to save the environment by reducing the dredging of natural resources and air pollution in cement factories which produce a lot of CO2 emissions through the use of marble industrial waste. By reducing the amount of cement by 25% and replacing it with Carbon Graphite Particle Marble Powder for concrete construction work with a design quality of K-250 or fc' 20.75 MPa by using it in buildings by the sea under the influence of sea air, the concrete quality is obtained higher than the quality design concrete is 22.76 MPa > 20.75 MPa. The compressive strength testing process was carried out based on ASTM C 39/C 39M - 05. Meanwhile, for workability, based on the slump test results, a 12 cm slump value was obtained with the testing process referring to SNI 1972: 2008 and ASTM C143/C143M-12. Refining marble waste using a grinder with a capacity of 5.5 HP equipped with a 200-micron filter. The combustion process uses a high-pressure combustion engine with combustion capabilities of up to 20000 C. Carbon particles are obtained at temperatures between 8500 C and 9000 C for 120 minutes. Temperature measurement using an Infrared Thermometer with a capacity of up to 15000 C.

A Review on Enhancing Quality of Self-Compacting Concrete by Used Cement Plastic Bag

Abstract: Plastic waste is a vital solid waste due to its un-decaying properties with respect to time, but plastic waste has interlocking properties that lead to enhancing the interlocking properties of the concrete. Self-compacting concrete is concrete with high workability and does not need vibration it is good for complex structural elements. So high-strength concrete production becomes typical but the interlocking properties of the plastic waste can be given a suitable direction for the strength parameter of self-compacting concrete. The major plastic waste source at the site is the cement plastic bags, cement bags are made of polypropylene polymer therefore they cannot react with cement, but are fibrous in nature and perform good interlocking properties.

Performance assessment of mechanical properties of green normal strength concrete produced with metakaolin-cement coated recycled concrete aggregate for sustainable construction

Reusing demolished concrete waste is a promising alternative to natural aggregate for resource conservation and achieving sustainable environment. However, there is a need to improve their quality and performance in new concrete. Therefore, this study aims to examine the mechanical performance of normal strength concrete containing metakaolin-cement coated recycled concrete aggregate (RCA). Three mixture batches were produced at water-cement ratios (w/c) of 0.25 and 0.45. The first batch is control mix, while the second and third batches contained uncoated RCA and metakaolin-cement coated RCA (TRCA) respectively. Materials characterization and workability of fresh concrete mixes were carried out. Compressive and split tensile strengths and water absorption tendency of hardened samples were determined. Morphology of selected concrete samples was analysed with scanning electron microscopy (SEM) with energy dispersive x-ray (EDX). The experimental results were further analysed with central composite design (CCD) response surface method. Results show improvements in the physical properties of RCA aggregates and declining trends in slump values. However, relative to the control mixes, concrete mixes containing TRCA exhibited significant improvement in strength performance and low water absorption tendency compared to RCA concrete mixes. This was corroborated by the response surface models showing that both w/c ratio and TRCA amount significantly influenced the strength and water intake performance of the concrete. The study demonstrated that TRCA can be deployed as an alternative for natural coarse aggregate up to 50% substitution in making normal concrete for structural purposes.

Effects of Chemicals Exposure on the Durability of Geopolymer Concrete Incorporated with Silica Fumes and Nano-Sized Silica at Varying Curing Temperatures.

Durable concrete significantly reduces the spalling caused by chemical damage. The objective of current research is to substitute cement with supplementary such as fly ash (FA), ground granulated blast furnace slag (GGBS), and alccofine (AF). Additionally, the impact of nano-silica (NS) and silica fumes (SF) on the GPC durability when cured at various temperatures has been attempted. In order to perform this, GPC samples were produced by combining NS and SF at proportions of 0.5% NS + 5% SF, 1% NS + 10% SF, and 1.5% NS + 15% SF, and then cured at temperatures of 27 °C, 60 °C, 90 °C, and 120 °C, respectively. In this research, all concrete specimens were continuously immersed for twelve weeks under four different chemicals, i.e., HCl (2%), H2SO4 (2%), NaCl (6%), and Na2SO4 (6%). The influence of chemical attack on the qualities of concrete was examined by evaluating the water absorption, sorptivity, loss of mass, and loss of GPC strength. The durability aspect is also studied by visual appearance and mass loss under harmful chemical attack. The combination of GPC with integrated NS and SF affords great resistance against chemical attacks. The percentages of these two components are 1.5% and 15%. For GPC specimens, when cured at 90 °C, the resultant strength is found at its maximum.

PENGARUH SUBSTITUSI CANGKANG KERANG DARI ENDE NTT TERHADAP KUAT TEKAN DANKUAT LENTUR BETON fc’= 19,3 MPa

The use of concrete for basic construction materials today is indeed increasing rapidly along with the development of construction construction.Only a concrete quality of 19.3 MPa (fc '= 25 MPa) was considered in this study. Since cement, aggregates, sand and water are extracted from nature, they must be limited. So in this study using additional material clam shells. One of them is shells, shellfish waste or shells are usually only used as decorations or toys so that there is still a lot of waste wasted. Inside the shell, the clam contains pozzolan chemical compounds, namely lime (CaO), aluminum oxide and silica. It can be expected to improve the quality of concrete.
 As a result of compressive strength test by changing the clamshell to 0%, 10%, 20%, 30%, 40% and 50%, the average compressive strength value of 0% (ordinary concrete) was 15.81 MPa. The addition of a 10% clam shell results in an average compressive strength value of 20.58 MPa. For the addition of clam shells by 20% obtained an average compressive strength value of 23.37 MPa. 30% yields an average compressive strength of 40.31 Mpa, to 40% of 29.12 Mpa. As for the addition of 50% clam shells, the average compressive strength value is 24.79 Mpa. Thus it can be concluded that the addition of clam shells 30% compressive strength value is higher than the compressive strength value of concrete with the addition of clam shells 0%, 10%, 20%, 40%, and 50%The flexural strength test value in terms of the maximum average moment on the beam for each variation of the test specimen is maximum moment value 75.02 kN.m for 0% variation, maximum moment value 62.52 kN.m for 10% variation, maximum moment value 68.77 kN.m for 20% variation, maximum moment value for 30% variation 62.52 kN.m, 40% variation at maximum moment value of 62.52 kN.m. Therefore, the percentage of specimens that can withstand the highest load in the flexural strength test is 0% and the maximum moment value is 75.02 kN.m.

UTILIZATION OF MARBLE-CEMENT POWDER MODIFIED WITH GRAPHITE CARBON PARTICLES ON CONCRETE CONSTRUCTION FOR BUILDINGS IN SEASIDE AREAS

This research aims to utilize marble industrial waste which is not utilized optimally and reduce air pollution as a result of cement production in cement industrial factories which produce a lot of CO2 emissions. The results of this research indicate that the use of 25 % Graphite Carbon Marble Particle Powder, to replace 25 % of the cement volume in making concrete with quality plans K-250 or fc’ 20,75 MPa. The results obtained are higher concrete quality than the quality of each concrete planned for the DCT type = 22,39 MPa > 20,75 MPa, DCL type = 22,76 MPa > 20,75 MPa, WCT type = 22,14 MPa > 20,75 MPa and WCL type = 22,89 MPa > 20,75 MPa. The compressive strength testing process is caried out based on ASTM C 39/C 39M – 05. Meanwhile for workability based on the results of the slump test, a slump value of 12 cm is obtained with the testing process referring to SNI 1972:2008 and ASTM C143/C143M-12.

Recommendations for quality control in industrial 3D concrete printing construction with mono-component concrete: A critical evaluation of ten test methods and the introduction of the performance index

The critical assessment of the applicability of fresh concrete test methods for characterizing printable concrete quality and its structural build-up rate is rare in the literature. To address this gap, this study evaluates the potentials and limitations of eight offline test methods (hand vane, rheometer, compressive strength, squeeze flow, penetrometer, ultrasonic pulse velocity, slump, and flow table) and two inline test methods (slug test and extruder torque measurement). This research proposes a new parameter called “performance index” to assess the capability of any test to detect structural buildup. The study establishes a ranking of the eight offline tests on the proposed performance index and evaluates the advantages and disadvantages of each test in terms of portability, price, required human labor, and material. The results of this study can be used as a first guideline to select a proper quality control test for industrial 3D concrete printing construction.

Effect of typical formworks and release agents on aesthetical surface quality of concrete

This work involved investigating formwork surface characteristics and concrete surface quality. The results show that release agent types and formwork materials have a great impact on the wettability of a formwork–concrete interface, although all the formwork surfaces, with or without release agents, are hydrophilic. Remarkably, inhomogeneous roughness characteristics are only observed for a steel formwork. Plywood and steel formworks have almost the same roughnesses; however, the roughness profile of plywood is sharper than that of steel. Mineral oil always correlates with larger surface voids and higher surface void ratios (SVRs). Steel formworks significantly increase SVR, compared with plywood and plastics formworks. When SVR < 1‰ and the proportion of small voids (<500 μm) > 50%, the concrete surface appears to be bughole-free. Rusty stains left by a steel formwork aggravate concrete discoloration, especially when water-soluble release agents are applied. To improve concrete surface quality, plywood formwork is more favourable, although release agents and vegetable-oil-based emulsion are more suitable for plastics formworks. The surface area roughness of concretes is mainly determined by that of formworks. The typical microgroove feature on a formwork surface leaves no trace on the formed concrete surface; this might be owing to the difference in dimension between microgrooves and cement particles and the presence of release agents.

Study of Pedestal Column Foundation of Heater Structures After a Fire Accident

This paper has presented the study of concrete experiencing the fire of the pedestal column of the heater foundation structure after the fire accident. . The evaluation was done with the analytical method, which was conducted to find out the actual condition of an existing structure. Structure or components of the structure are categorized as a safe condition; if its design strength is greater or equal to the required strength or ORn >= Ru. Evaluation of the pedestal column structure with the analytical method was done by visual inspection, concrete quality inspection, cracking depth inspection, structural analysis with the finite element software and strength calculation of structure according to the requirement of SNI 2847 2013. The equipment used for concrete quality inspection is Digischmidt Hammer and PUNDIT. The result showed that there was a degradation of the concrete quality of less than 15%. However, with this condition, all of the pedestal column structures are still in a safe condition in receiving the load operation. 
 Keywords: Concrete experiencing a fire, Concrete evaluation, Pedestal column, Required strength, Design strength.

THE EVALUATION OF THE CAUSES OF RETAINING WALL STRUCTURE FAILURE AT A RIVER BASED ON SNI 2847:2013

In this paper, the application of SNI 2847:2013 in the evaluation of the case of a retaining wall failure is presented. The method is the analytical retaining wall evaluation, which consisted of visual inspection in the field, depth measurement of pile and sheet pile, and the quality test of concrete material. The data were used as input in structure modeling using Finite Element Method (FEM) software to calculate each structural member's required strength (Ru). The calculation was done to obtain the design strength (ØRn) of the structural member. The retaining wall is considered safe if its design strength is greater than or equal to the required strength or ØRn ? Ru. If this condition cannot be fulfilled, the retaining wall is considered failed, and then the causes of failure would be performed. The result showed that the depth of the pile and sheet pile is less than the required minimum depth, and concrete quality is below the specification mentioned in the as-built drawing data. According to structural analysis and calculation of site investigation data, it could be known that the causes of retaining wall failure are the design strength is smaller than the required strength and the vertical moment due to its self-weight is much smaller than the horizontal moment due to soil and water pressure, so it causes the structural sliding.

Proposal for classification of concrete quality based on accelerated carbonation tests

Reinforcement corrosion is a problem affecting the durability of most concrete structures. When concrete is employed without proper care, it may function inadequately as a barrier, allowing aggressive ions or acidic substances in the atmosphere to attack steel rebars. The principal agents responsible for corrosion are carbon dioxide (CO2) and chlorides (Cl-). Most carbonation research is based on accelerated carbonation tests. Thus, there is an important need to evaluate this process, via comparison with samples having undergone natural carbonation. However, as long-term analysis is required, such studies are scarce. This study proposes classifications of concretes regarding carbonation risks, based on carbonation coefficients obtained through accelerated tests (Kacel). An extensive literature review is conducted, compiling Kacel results and their correlations with values of natural carbonation coefficients (Knat). The results provide an improved classification of concretes regarding their resistance to carbonation, which will help researchers and designers to specify the concrete.

The rapid chloride migration test as a method to determine the chloride penetration resistance of concrete in marine environment

This paper analyses the use of the rapid chloride migration test (RCMT) in assessing the long-term chloride penetration resistance of concrete in real marine environment. Based on extensive experimental data, RCMT results were related to the diffusion and penetration properties of a wide range of normal weight and lightweight aggregate concretes, 5-year exposed under real submerged (XS2) and wetting and drying (XS3) conditions. Most usual structural concrete with different water/binder, types of aggregates and binders were covered. Concretes were ranked in terms of their chloride durability performance in real environment and a new classification was proposed to evaluate the durability of concrete to chloride attack. Classes were established based on service life prediction analysis. Overall, it is shown that the RCMT classification can distinguish the resistance to the chloride penetration of different concretes under distinct exposure environments, allowing for an expeditious method to evaluate the concrete quality.