Concrete Quality Research Articles

UTILIZATION OF HIGH-VOLUME FLY ASH AS A SUPPLEMENTARY CEMENTITIOUS MATERIAL IN ENVIRONMENTALLY FRIENDLY CONCRETE

Innovations in material technology are expected to reduce the use of commercial cement and replace it with other environmentally friendly materials with the same performance as normal concrete. Aim: This study aim to analyze the mechanical property of High-Volume Fly Ash Concrete (HVFAC) using F class fly ash with different mix percentages. Methodology and Results: The experiment was conducted in laboratory scale. Four variations of test specimens consisted of: 1 variation (F0), which is conventional concrete with 100% Portland cement as control specimen, and three variations of HVFC (F70, F80, and F90), which were made with fly ash content (%) 70, 80, and 90 of total cementitious. Fresh concrete testing to determine workability, while hard concrete testing is done by density and compressive strength tests at the age of 3, 7, and 28 days on specimens that have been treated with the water submerged curing method. Conclusion, significance, and impact of study: All HVFAC specimens fulfill the Self Compacting Concrete (SCC) category. The compressive strength test results at 28 days showed that the addition of fly ash percentage caused a decrease in compressive strength values in all HVFAC variants, but still exceeded the minimum requirements of high and medium quality concrete. All HVFAC variations meet the requirements of ASTM C618-23 based on the evaluation of Strength Activity Index (SAI) values at 7 and 28 days of age. The utilization of 90% fly ash as a cement substitute resulted in an environmentally friendly concrete product based on the concept of cleaner production.

Relationship between chloride ingress and concrete cover quality of inland structures exposed to deicing salts

The apparent diffusion coefficient of chloride ions is used to evaluate the durability of existing concrete structures against chloride attack. The coefficient requires in situ measurements of chloride profiles, which use destructive sampling techniques, such as core drilling. In this study, the relationship between the apparent diffusion coefficient of chloride ions obtained from destructive tests and the air-permeability coefficient obtained from a non-nodestructive Torrent method in the existing road bridges exposed to deicing salts was analyzed. The obtained relationship was different from the common trends obtained from laboratory chloride-immersion tests and in situ measurements in marine/coastal concrete structures. Additional cyclic wetting and drying tests in a laboratory revealed the effects of environmental differences on the apparent diffusion coefficient of chloride ions. A higher ratio of the drying period, in the case of deicing salts, reduced the apparent diffusion coefficient.

Research of foam concrete quality by two-stage foam injection method in comparison with classical foam concrete

The article presents a method of production of foam concrete, which involves two-stage injection of foam. The proposed method involves improving the pore structure of foam concrete, due to a more uniform distribution of pores throughout the volume of the material. Laboratory tests were carried out for two types of samples, represented by the proposed method of foam concrete production by two-stage foam injection with the use of modified additive in comparison with the classical foam concrete. The density of Type 1 samples varies from 410 to 793 kg/m3 (coefficient of variation from 5.12 to 7.31%), while the density of fiberboard samples lies within the range from 539 to 655 kg/m3 (coefficient of variation from 2.66 to 3.14%). The results of greater variation of densities by height in the Type 1 sample relative to the Type 2 sample indicate the influence of the technological process of foam concrete production on the quality of the pore structure of the material. The results of strength evaluation showed a large scatter of Type 1 samples in relation to Type 2 samples. The highest values of CM strengths are logically observed in the lower part of the sample and the lowest in the upper location: 44.04 and 32.33 kg/cm2 (coefficient of variation from 5.15 to 9.54%). For Type 2 samples, the same values are 55.18 and 44.44 kg/cm2, for the lower and upper locations, respectively (coefficient of variation from 2.79 to 5.35%). The results of thermal conductivity measurements of Type 1 samples range from 0.098 to 0.203 W/m0C (coefficient of variation from 4.59 to 11.88%), while the densities of Type 2 samples lie between 128 and 162 W/m0C (coefficient of variation from 3.38 to 3.55%).

Compressive Strength Of Concrete The Time Setting Of Application Of Plastiment® P-121 Additive Mixture

Infrastructure growth requires large quantities of concrete, a problem of concern distance between the batching plant and location of different casting locations, the process mixing and transporting to casting location requires time that can exceed the cement setting time. Plastiment helps improve the strength, durability and general quality of concrete. This research aims to determine the compressive strength of concrete at setting times of 60, 90 and 120 minutes using 150 mm x 300 mm specimens with variations in addition of plastiment of 0.20% and 0.40% of the cement weight. Primary data the form of material testing data and concrete compressive strength for each variation and secondary data is in the form of additives and the properties of cement used. The test results show that the compressive strength of concrete at 60, 90 and 120 minutes by adding Plastiment® P-121R at a variation of 0.20% is 17.55, 18.12 and 18.85 MPa while giving a dose of 0.40% is 17 .27, 19.82 and 22.08 MPa. Addition of plaster can meet the slump value requirements at each time variation and in contrast to normal concrete the slump value is not met at each time variation with the concrete having dried during mixing.

ANALISIS KUAT TEKAN BETON MODIFIKASI POLYETHYLENE TEREPHTHALATE (PET)

Concrete is one of the most commonly used materials in the world of construction, both simple and complex. Concrete is the most widely used construction material as a building material so it is necessary to know the classification and characteristics of the material or construction material to be used. The use of waste in concrete mixtures is a trend in the development of concrete today because it helps reduce environmental pollution, by utilizing and processing solid waste generated by industrial waste and municipal waste, as well as reducing the use of natural materials which are increasingly limited in number. The most abundant waste is polyethylene terephthalate (PET) plastic. Therefore, it is necessary to use PET plastic as an effort to create an alternative technology that is innovative enough to improve the quality of concrete by using fiber concrete. So this research method uses variations of PET as much as 0.1%; 0.25%; and 0.4% as a substitute for some fine aggregates. The plastic was cut or chopped with a length of 5 cm and a width of 1-3 mm. The results showed that concrete with PET plastic fiber increased up to 12.96% compared to normal concrete.

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

Experimental study on the performance of polymer pervious concrete using recycled concrete aggregate

The phenomenon of population growth exerts a significant influence on alterations in land utilization, hence causing a reduction in the catchment area and subsequently giving rise to issues related to surface runoff. Stormwater control can be effectively achieved with the use of pervious concrete, which is a porous material that allows surface water to seep into the underlying soil. Because of its ability to transfer surface water into the ground through its pores, pervious concrete was developed as a stormwater management tool to address these issues. Unfortunately, previous concrete has lower quality than normal concrete due to its voids. Several investigations have been carried out to enhance the quality of earlier concrete, one of which involves the use of polymers to strengthen the binding between particles. The primary objective of conducting experimental investigations on polymer pervious concrete incorporating recycled concrete aggregate is to evaluate the performance of polymer pervious concrete using recycled aggregate concrete to support sustainable construction. The study revealed that incorporating recycled concrete aggregate into pervious concrete results in a decrease in its compressive strength. On the other hand, it has been demonstrated that using polymer as an adhesive effectively increases the compressive strength of pervious concrete that contains recycled concrete aggregate.

Large rectangular cross-section tunnel undercrossing urban road by micro pipe jacking and joint assembly structure (MPJ & JAS) method in soft soils

With the continuous construction of urban traffic roads, more and more new roads are cut off by existing roads to form “dead end roads”. There is an urgent need for a trenchless method suitable for urban ultra-shallow overburden to build the undercrossing tunnel. To solve this problem, this paper proposed the micro pipe jacking and joint assembly structure (MPJ & JAS) method, which has the characteristics of shallow burial depth, low cost, short construction time, flexible cross-section setting and high space utilization. The MPJ & JAS method construct a large cross-section tunnel through assembling small cross-section elements, quite different from traditional methods. Therefore, this paper designed a CT-shaped integrated joint, the mechanical performance of which was verified and clarified by tensile test. The bending test and finite element (FE) analysis proved the reliability of MPJ & JAS tunnel structure, and confirmed the structure performances such as the failure models, crack behaviors, load–deflection response and stress–strain distribution. Moreover, the influences of the steel plate thickness, concrete strength and shear connector spacing were determined by the FE analysis. On the basis of test results and reasonable assumptions, a theoretical design method considering the influence of the CT-shaped integrated joint was proposed, which can effectively predict the bending strength of the MPJ & JAS tunnel structure with an error of less than 10%. Finally, in view of the characteristics of the MPJ & JAS method, the suitable micro pipe jacking machine, soil reinforcement measure, hydraulic traction construction technology, high-precision guidance system and concrete construction quality detection method based on the phased array ultrasonic imaging technology were developed, supporting the accurate and efficient construction of the MPJ & JAS tunnel.

An Experimental Investigation on Self-Healing Concrete Made of Bacteria with Varying Doses

Abstract: The employment of carbonate-producing bacteria as a new approach to enhance the qualities of concrete has attracted a lot of interest since it is thought to be innocuous to theenvironment, natural, and maybe advantageous. This is a result of the favorable implications attached to these traits. The use of microbially induced carbonate precipitation as a remedy for several problems affecting concrete, such as fracture healing, reduction and change of porosity and permeability, and more, has been the subject of much investigation. Concrete crack healing is one of the topics that have been researched. Additionally, it has been shown that the procedure of bacterial carbonate precipitation, also known as bio deposition, contributes to the development of concrete's compressive strength. There has not yet been a thorough investigation of the research relating to the appropriate bacterial solution dose and its effect on concrete durability. This might occur as a result of the project not receiving enough time to complete it. As a result, it has been decided that an investigation will be conducted in order to determine the proper quantities of bacterial solution required for concrete. To do this, several concrete cube samples will be made using varying amounts of bacterial solution, such as 15 ml, 30 ml, 45 ml, 60 ml, and 75 ml, respectively. These quantities will be added to the appropriate moulds. This will allow you to determine the proper dosage of the bacterial solution to employ. In order to determine the optimal dosage that should be used, these various samples are also put through a battery of tests using a variety of laboratory techniques, such as the properties of materials, slump cone test, a compressive strength testing machine, an ultrasonic pulse velocity test, plate count cells, and scanning electron microscopes, Rapid Chloride Penetration Test (RCPT), Acid attack test.

Effect of variations in concrete quality on the crack width in rigid pavement

Cracks pose a significant issue in rigid pavement, leading to substantial damage. The manual mixing and casting of road pavement concrete underscore the importance of concrete quality as a critical parameter. This study investigates crack behavior by varying concrete quality. Loading is performed statically using line loads, shedding light on the impact of concrete quality on crack development. The concrete to be used has a quality fc' of 15 MPa, 25 MPa, and 35 MPa. The fine aggregate used in this study was Lumajang black sand, while the coarse aggregate used was machine crushed stone, and Portland Composite Cement (PCC) was used in all concrete mixes. The reinforcing steel used had a quality fy of 480 MPa, with a reinforcement ratio of ρ=0.010, which was converted to 5-D16 reinforcement. The subgrade density used to support the specimens had a CBR value of 10 %. Specimen dimensions were 2×0.6×0.2 m for length, width, and thickness. Pavement plates, 30 cm thick, were placed on leveled subgrade soil in a steel box set to achieve a 6 % CBR reading. Hydraulic jacks, monitored by a load cell, applied monotonic static loading with 2 kN intervals, reaching a maximum load of 200 kN. Steel tension and plate settlement were measured using a tension sensor and Linear Variable Differential Transformer (LVDT), respectively. A data logger recorded readings, and crack widths were captured by a digital microscope with 0.01 mm accuracy. Experimental results show that low concrete compressive strength values result in larger crack widths, and vice versa. Cracks also occur at earlier loading of concrete quality fc' 15 MPa. In addition, experiments show that the reinforcement stress value has a significant influence on crack width in specimens with low concrete quality

Soft computing implementations for evaluating Los Angeles abrasion value of rock aggregates from Kütahya, Turkey

The Los Angeles abrasion value (LAAV) of rocks is a critical mechanical aggregate property for designing road infrastructures and concrete quality. However, the determination of this critical aggregate property is labour-intensive and time-consuming and thus, in the literature, there are many predictive models to estimate the LAAV for different rock types. However, most of them are based on classical regression analyses, limiting their broader usage. In this study, several soft computing analyses are performed to develop robust predictive models for the evaluation of LAAV of rocks in the Ilıca region (Kütahya – Turkey). The main motivation for implementing soft computing analyses is that precise predictive models might be useful when exploring suitable rock types that are manufactured in crushing–screening plants. For this purpose, a comprehensive laboratory schedule was established to obtain some inputs for the evaluation of LAAV. As a result of the soft computing analyses, four robust predictive models are developed based on artificial neural networks (ANN), multiple adaptive regression spline (MARS), adaptive neuro-fuzzy inference system (ANFIS) and gene expression programming (GEP) methodologies. The performance of the proposed models is investigated by some statistical indicators such as R2 and RMSE values and scatter plots. As a result, the ANFIS-based predictive model turns out to be the best alternative to estimate the LAAV of the investigated rocks.

Perencanaan Gedung Bertingkat 5 Lantai Asrama Putri Pondok Pesantren Hasyim Asy’ari Bangsri Jepara

The development of the world of Islamic education in Indonesia also includes Islamic boarding schools, Hasyim Asy'ari Bangsri Jepara Islamic boarding school is one of the best Islamic boarding schools, to support the smooth teaching and learning, it is necessary to have adequate student facilities and facilities. This research aims to help fulfill the capacity of santri facilities and infrastructure at the Hasyim Asy'ari Bangsri Jepara Islamic boarding school. The building structure calculations were reviewed for dead loads, live loads and earthquake loads using the SAP 2000 program. The structural calculations carried out included roofs, floor plates, beams, columns, stairs, sloofs and foundations. The building planning location is Jl. Jepara-Bangsri No. 9, Krasak Bangsri, District. Bangsri, Kab. Jepara, Central Java 59452. From the structural planning, the roof structure is obtained with 2L steel trusses 50.50.7, floor plate 130 mm ∅ 12-100, beam B1 500x300 mm 10 D19, beam B2 400x250 mm 10 D19, column K1 500x500 mm 18 D19, column K2 400x400 mm 12 D19, ladder plate thickness 150 mm ∅ 12-150, sloof 500x300 mm 9 D19, pile cap foundation 160x160x60 mm, pile D30 cm 6 m long, with concrete quality (f'c) = 30 MPa, reinforcement quality (fy) = 400 MPa and (fy) = 240 MPa. The programs used are Microsoft Office, Microsoft Excel, Autocad, SAP 2000, and SketchUp.

Identifying the influence of split tensile strength to crack width of high-strength reinforced concrete beam with polypropylene fiber from medical mask waste

Cracks in concrete structures due to tensile weakness can be repaired by using fiber concrete, including medical mask waste as an additive in high-strength concrete mixes. This research the influence of polypropylene fiber from medical mask waste on the mechanical characteristics, flexural behavior, and crack width of high-strength reinforced concrete (RC) beams. The initial stage involved examining the properties of the concrete constituent materials. The testing process was based on a high-strength concrete mix design using the Aitchin method mix design sheet. Compressive strength and split tensile strength were tested at fiber content (0 %, 0.15 %, 0.20 %, and 0.25 %). The three-point flexural testing procedure was carried out at 28 days on 1200×100×150 (mm) RC beams. The use of LVDT, strain gauge, and other measuring devices supported the acquisition of the required data. The results showed that the split tensile strength reached the optimum value of 66.19 MPa at 0.24 % fiber content. Polypropylene fiber from medical mask waste in RC beams showed a positive impact on reducing crack width at increased split tensile strength. Waste mask fiber content of 0.15 %, 0.20 % and 0.25 % gave stable and better results compared to 0 % content (no fiber). With high steel stress (fs), and high strain, it offers the potential to improve the mechanical properties of high-strength concrete, thereby reducing the width of cracks that occur. This improves the tensile weakness of the concrete. The effect of split tensile strength on the crack width (w) of beams with the formula approach: wexp=3.74ftf-1.513, wan=0.187ftf-0.022 shows that the experimental results have a significant effect on decreasing the crack width that occurs in high-strength RC beams, thereby improving the quality of concrete

The influence of methods of concrete quality control by physical and mechanical parameters on the reliability of building structures

Introduction. The construction technical control system evaluates the physical and mechanical properties of concrete on the base of testing a series of samples taken from a batch of concrete. It is necessary to take into account the influence of the control method on the quality of concrete structures and their reliability.
 
 Aim. Creation of a technical control system that should eliminate the causes of the identified risks by reducing the impact of the identified causes.
 
 Materials and methods. The control method affects the reliability of concrete structures being built and is evaluated from the point of view of choosing the number of samples and discarding the minimum strength values in the series. The results of the control of a series of concrete samples for 6 samples selected in such a way as to ensure compliance with the declared class when discarding 2 minimum sample values are compared.
 
 Results. As a result of the analysis of the impact of the methodology on quality and reliability: class B turns out to be 2 steps lower than the prescribed one, the in-series coefficient of variation exceeds the permissible one by 8 %, and the reliability level is significantly lower by 36 %.
 
 Conclusions. The conducted research shows an underestimation of the methodological component of material control, which can leave significant gaps in the system of technical control of construction products and does not allow to ensure the required level of reliability of structures.

High performance selfcompacting concrete with addition of sugarcane bagasse ash

With the advancement of studies on self-compacting concrete (SCC), improvements in the strength and quality of concrete can come from products with lower costs and non-conventional, such as sugarcane bagasse ash (CBC). Therefore, the main objective of the work is to demonstrate that it is possible to develop SCC with lower cost, good resistance to axial compression, with good physical properties and sustainable, as the ash does not have an adequate destination, it is simply discarded in the environment, without aggregation of value. This ash can be used as a replacement for cement, as it has pozzolanic characteristics and is a material that reduces voids in concrete, making the concrete obtain better properties, such as those observed here in the segregation and axial compression resistance tests, in addition to to reduce the cost of concrete.

High-temperature effect on the mechanical behavior of recycled fiber-reinforced concrete containing volcanic pumice powder: An experimental assessment combined with machine learning (ML)-based prediction

The increasing volume of waste generated by various activities has increased interest in using waste to create sustainable construction materials to achieve possible benefits. In addition, using recycled materials to produce fresh concrete is a desirable option because of its low cost, lower landfill space requirement, and the completed concrete quality. Therefore, an experimental inquiry is undertaken to ascertain the impacts of up to 20 wt% cement displaced by Volcanic Pumice Powder (VPP) with the incorporation of 1% and 2% Recycled Nylon Fiber (RNF) on the mechanical properties of concrete composites following room temperature to high-temperature (600 °C) exposure. Fresh concrete characteristics tests were performed, including slump, compacting factor, Kelly ball penetration, and density. The heat resistance of the concrete was then measured by calculating the percentage decrease in weight, the splitting tensile strength, and the compressive strength of the specimens. Heating mainly raised VPP's pozzolanic reactivity and lowered high vapor pressure through melting RNF. Therefore, VPP and RNF-treated concrete had superior mechanical performance than control concrete even when exposed to elevated temperatures. Further, the microstructural modifications brought on by RNF and VPP additions were also explored by deploying Scanning Electron Microscopy (SEM). The use of VPP in concrete led to an improvement in fresh properties, while RNF demonstrated deterioration in the same qualities. Despite this, supervised machine learning techniques are a central focus of this investigation because of their potential to predict concrete characteristics accurately. To predict the fresh and mechanical characteristics of concrete, both the Random Forest (RF) and the K-Nearest Neighbors (KNN) algorithm, along with their ensemble model counterparts, were explored. The outcomes revealed that RNF and VPP considerably improved the concrete's heat resilience and mechanical characteristics and halted the concrete composites' explosive spalling behavior at 600 °C temperatures. To prevent strength loss at high temperatures, it was discovered that adding 1% RNF content to concrete with 10% VPP was the best combination. In addition, the high coefficient correlation (R2) value of the RF and the ensemble model indicates great accuracy in outcome prediction, while the low R2 value of the KNN model indicates that the KNN model is less accurate.

Influence of Unit Water Content Control on Concrete Performance in the Ready-Mixed Concrete Production Process.

This study examined the effects of increasing concrete unit water content and artificially controlling water content on concrete performance in the production process of ready-mixed concrete. Results showed that changes in the unit water content of 20 concrete mix proportions without air-entraining significantly reduced concrete compressive strength, increased porosity, and in-creased occurrence of bleeding. A unit water content increase of 25 kg/m3 or more may reduce the compressive strength of concrete below the design standard and significantly affect the occurrence of bleeding water. Moreover, an extra unit water content of at least 25 kg/m3 could significantly affect the diffusion of chloride ions in the concrete. The carbonation depth of concrete was extremely high with the increase in unit water content and water addition. In the production of concrete requiring at least normal strength or durability, the extra water change to total unit water content should be maintained at 15 kg/m3 or less. And a water-cement ratio of 48% or less and a unit water content of 155 kg/m3 or less are considered effective for management of concrete quality. Considering the aggregate type, absorption rate, and moisture state, the management of unit water content error in concrete production processes requires greater.

Organic Admixtures as Additive: An Initiative to Reduce Carbon Dioxide Emission due to Concrete

AbstractConcrete is a material which is being used extensively for construction worldwide. Concrete provides high strength, durability, impermeability, fire resistance, and hence provides a safe place for living. It is the composite of cement, aggregates, and water. In modern construction, chemical admixtures are also used to elaborate the properties of concrete like strength, workability, etc. but the chemical admixtures have adverse effects on environment at the time of production and post‐production also. Whereas organic admixtures are extracted organically from plants and animals without addition of any external chemicals. Many organic admixtures are used in lime concrete/mortar traditionally. The purpose of this paper is to enlighten the effect on quality of concrete by addition of organic additives jaggery and sticky rice pulp, which will in turn reduce the cement requirement and overall CO2 emission in the environment.

Pengaruh Penambahan Limbah Bulu Ayam Terhadap Kuat Tekan Beton K-250

Along with the times, various innovations have been made to improve the performance of concrete, Innovations carried out include aiming to produce and value structural materials that have good properties with economical and economical methods and costs, Efforts to improve the quality of concrete are also carried out by mixing other ingredients in the mixture. In this study, the author used chicken feather fiber as an added ingredient to the mixture concrete. This study aims to find out how the process of making concrete with added chicken feather waste with an additional composition of 0.1%, 0.5%, and 1.5%, and whether the added material of chicken feather waste with a composition of 0.1%, 0.5%, and 1.5%, can increase the compressive strength of concrete or vice versa. In this research method using the experimental method, the test objects made for each addition to the percentage of chicken feather waste are as many as 3 samples, with a cylindrical mold size of 15 cm in diameter with a height of 30 cm, by passing the treatment process for 28 days. The conclusion of this study is that concrete is added with chicken feather waste with variations of 0.1%, 0.5%, and 1.5% addition, the planned compressive strength is 20.8 Mpa. A decrease in compressive strength was produced in each use of added chicken feather waste with a composition of 0.1%, 0.5%, and 1.5%, the more added chicken feather waste, the compressive strength value of concrete decreased, the initial normal composition produced a compressive strength of 21.56 Mpa, while the composition of 0.1% decreased with a compressive strength result of 10.64 Mpa, then with a composition variation of 0.5% decreased again with a compressive strength value of 3.21 Mpa. And for a composition variation of 1.5% it decreases with a compressive strength value of 0.16 Mpa. With this research, it is known that chicken feather waste material cannot be an alternative to add concrete mixture in the future.

Implementation of Mini Piles and Retaining Wall in the Construction of the North Kalimantan Provincial DPRD Building in Bulungan Regency

Piles are used as the foundation for a building's construction when the underlying soil beneath the structure lacks sufficient bearing capacity to support the weight of the construction and its load, or when hard soil with enough bearing capacity lies at a significant depth. Retaining walls are a type of civil construction built to withstand the lateral active pressure of soil or water. Therefore, the construction of a retaining wall must be planned and designed to safely counter potential forces that could cause structural failure. The purpose of this writing is to understand the implementation of mini pile foundations and retaining walls concerning the stability control of the retaining wall against sliding, overturning, and soil-bearing capacity. The observational method used involves collecting secondary and primary data. The mini pile foundations are driven to a specified depth, with each pile segment being 4.0 meters long, and this piling activity aligns with the plan. The retaining wall used is a cantilever retaining wall with concrete quality K-300 f’c 25 MPa, where the successive heights, upper width, and bottom width of the retaining wall are 4.5 m, 0.3 m, and 2.7 m, respectively.