Concrete Mix Water Research Articles

Advances in using seawater in slag-containing cement systems

The use of seawater as mixing water in concrete is motivated by an increasing danger of freshwater shortages. The factors restricting its use in concrete include a high risk of concrete structure degradation as well as steel reinforcement corrosion initiated by the chlorides and sulphates in seawater. The objective of this study is to evaluate the potential of ternary cementitious systems containing the substitution of a clinker constituent in cements with ground granulated blast furnace slag (GGBFS) at rate of 45 wt% and 85 wt% and zeolite (10 wt%) mixed with seawater. Moreover, the effects of alkaline activators were evaluated as a potential method to compensate the low strength of high volume slag-zeolite-cement systems containing seawater. The hydration process was evaluated by means of calorimetry, X-ray diffraction (XRD) and scanning electron microscopy (SEM), and was supplemented by the compressive strength development (2, 7, 28 days) evaluation. It was found that presence of GGBFS in seawater-mixed systems, promotes an increase in the volume of low-calcium silicate hydrate gel-like phases, which (in addition to the layered double hydroxide phases) bind the Cl-- and SO42--ions of seawater. However, at high volume replacement level (85 wt%) the accelerating effect of seawater is limited resulting in slow rate of concrete strength gain. The proposed alkaline activation, allowed the strength enhancement, but also satisfied the conditions for the complete binding of Cl-- and SO42− -ions, due to the formation of zeolite-like alkaline aluminosilicate hydrates in the resultant cement matrix. It was found that the addition of natural zeolite accelerates hydration reactions and crystallization processes in cement systems. As an outcome, due to synergistic effect of seawater and alkali-activation, the proposed ternary blend containing 5 wt% of Portland cement exhibited only 24 % lower 28 days compressive strength when compared to freshwater-mixed Portland cement (90 wt%) – zeolite (10 wt%) reference mix.

Effect of Water Magnetization Technique on the Properties of Metakaolin-Based Sustainable Concrete

Using metakaolin (MK) in concrete with magnetized water (MW) has a high possibility to enhance concrete suitability. In this study, the effect of using MK and MW on concrete characteristics was studied through testing twelve concrete mixes. Seven ratios of MK were used in this study, namely 0%, 5%, 10%, and 20%, as an alternative to cement and +5%, +10%, and +20% as a cement additive. In addition, five water magnetization methods were applied on MK concrete. In the first stage of this study, the impact of different MK ratios on the workability of concrete, compressive strength, flexural strength, and tensile strength was studied using traditional tap water (TW) as the concrete mixing water. In the second stage, the best mix (best MK ratio) from the first stage was chosen to study the effect of the water magnetization method on concrete properties and to determine the best method for water magnetization. Scanning electronic microscope (SEM) analysis was also carried out on selected mixes to closely investigate the effect of MK and MW on concrete microstructure. The results showed that the best ratio of MK in concrete was +10% (MK as a 10% cement addition), and the best water magnetization method was to pass the water through 1.6 tesla then through 1.4 tesla magnetic fields. The SEM analysis confirmed the absence of pores after using MW instead of regular TW by increasing the calcium silicate hydrate (CSH) gel and reducing calcium hydroxide (CH). Using MK and MW enhanced the compressive strength by up to 33%, 32%, and 27% at 7, 28, and 365 days, respectively, and MW enhanced the workability by up to 3% compared to that of the control mix.

Production of Concrete Using Contaminated Water and Its Effects on Compressive Strength of Concrete

In saline environment and places where there is no access to clean water for concrete work, contaminated water is often used for mixing and preparation of concrete for different structural members of buildings and this practice is in complete violation of most approved standard codes for concrete production. This study is aimed at determining effects of the use of salt contaminated water on compressive strength of concrete with a view to providing mitigating measures. 150 mm cube samples were cast with these water samples. Compressive strength test was carried out on the cubes. Findings revealed that for potable water, the initial strength was retarded in the first 7 days, uniformly progresses through 14 days, 21 days until the 28 days. In the case of contamination of 1000 mg/litre, concrete strength follows the same trend as the control. As the quantity of contaminated salt increases after this stage, the compressive strength generally decreases. It was further observed that the contamination effects were not pronounced on the strength within the first 7 days. According to the 28 day compressive strength ranged from 23.26 to 15.78 N/mm2 as the concentration of contaminant (NaCl) in concrete mixing water ranged from 0 to 5000 mg/l. The study therefore concludes that the salt contaminated water have adverse effect on the properties of concrete. The use of salt contaminated water for concrete mixing is seen to favorable for strength development only at 4000 and 5000 mg dosages at early ages and reduction in long term strength.

Effect of magnetic treatment of mixing water on the behavior of cement-based materials: A review

Abstract Magnetic treatment technology for concrete mixing water is a cost-effective and environmentally friendly approach that can enhance the performance and durability of cement-based materials. This technology aligns with the principles of sustainable development. In their studies, researchers have utilized static magnetic fields (SMF) of varying intensities to treat regular water and produce magnetically treated mixing water (MTMW) for a specific duration. Various research laboratories have successfully employed MTMW in the production of cement-based materials such as cement paste, mortar, ordinary concrete, foam concrete, self-compacting concrete, and rubber concrete. The main objective of this investigation is to review previous research that evaluated the impact of MTMW produced using different methods on the fresh, hardened, durability, and microstructure properties of cement-based materials. Most studies revealed that magnetic treatment technology improves physical and chemical properties of regular water, including solubility, surface tension, and conductivity. Regarding cement-based materials produced with MTMW, most investigations have demonstrated a significant enhancement in mechanical strength, durability, and microstructure. However, it seems that some researchers may have exaggerated their findings regarding the effect of MTMW on mechanical properties. Consequently, further research is needed to validate these results. I recommend considering the utilization of the MTMW technique for all cement-based materials to enhance their mechanical strength and durability performance.

Investigation of the Effect of Magnetic Water and Polyethylene Fiber Insertion in Concrete Mix

The features of a concrete mix are determined by the hydration of cement, which is accomplished utilizing the water quality utilized in the mix. Numerous researchers have worked on integrating pozzolanic or nanoparticles to increase hydration processes and impart high strength to concrete. Magnetic-field-treated water (MFTW) has been used in a novel method to enhance the characteristics of concrete. Due to magnetization, water particles become charged, and the molecules inside the water cluster fall from 13 to 5 or 6, lowering the hardness of water and so boosting the strength of concrete when compared to the usage of regular water (NW). Magnetic water (MW) is used in advanced building methods and procedures to improve physicochemical qualities. This study focuses on analyzing water quality standards using physiochemical analysis, such as electrical conductivity (EC), pH, and total dissolved solids (TDS) using the MW at various magnetizations (0.9 Tesla (MW0.9), 0.6 Tesla (MW0.6), 0.3 Tesla (MW0.3). Tests were carried out to assess the fresh, hardened, and microstructural behavior of concrete created with magnetic water (MW) using techniques for microstructural characterization such as Fourier-transform infrared spectroscopy (FT-IR). According to the findings, the magnetic influence on water parameters improved significantly with increasing magnetic intensity. As compared to regular water concrete, the MW0.9 mix increased workability, compressive strength and splitting tensile strength by 9.2%, 32.9%, and 34.2%, respectively, compared to normal water concrete (NWC).

친환경 Carbon Eating Concrete 제조를 위한 나노버블 이산화탄소 용해 배합수 제조 기술 개발 및 최적화

친환경 Carbon Eating Concrete 제조를 위한 나노버블 이산화탄소 용해 배합수 제조 기술 개발 및 최적화

Characteristics of Sustainable Concrete Containing Metakaolin and Magnetized Water

In this study, fourteen sustainable concrete mixes containing metakaolin (MK) as supplementary cement material (SCM) and magnetized water (MW) as concrete mixing water were designed, prepared, tested, analyzed, and compared. The MK was used as a partial replacement of cement weight by 5%, 10%, and 20%, and as an additive to cement by 5%, 10%, and 20% of cement weight. The MW was used to fully replace tap water (TW) in concrete mixes and was prepared using two different magnetic fields of 1.4 tesla (T) and 1.6 T. This experimental research aimed to assess the characteristics of concrete manufactured with MK and MW. The mechanical and durability characteristics of fresh and hardened concrete were measured for the assessment. Microstructural and chemical analyses were carried out on selected materials and concrete mixes. The workability and compressive strength of the materials at 7, 28, and 365 days were measured, in addition to the splitting tensile strength at 28 days and the flexural strength at 28 days. The compressive strength at 365 days was conducted at 18 °C and 100 °C to study the effect of the applied variables on the concrete durability at different elevated temperatures. The microstructural and chemical analyses were conducted using a scanning electron microscope (SEM), energy dispersive X-ray (EDX), and Fourier transform infrared (FTIR) spectroscopy. The results showed that using 10% MK as a cement additive was the best ratio in this study, which enhanced all the measured mechanical characteristics when the TW or MW was used. Using MW instead of TW in MK concrete increased all the mechanical properties measured at 28 days by about 32–35%. The results of the microstructural and chemical analyses supported the compressive strength increase by showing indications of more C-S-H gel production and less CH when using MW in MK concrete. In addition, fewer micro-cracks and pores, and relatively denser concrete, were detected when using MW with 10% MK as a cement additive.

Possibility of Using Waste Materials as Substitutes for Gravel or Water in Concrete Mix

Analyzing the global waste management sector, we can see that some waste, due to its specificity, is a major challenge when it comes to its management. This group includes rubber waste and sewage sludge. Both items pose a major threat to the environment and human health. The remedy for this problem may be the solidification process, in which the presented wastes are used as substrates in the production of concrete. The aim of this work was to determine the effect of waste addition to cement in the form of an active additive (sewage sludge) and a passive additive (rubber granulate). An unusual approach to sewage sludge was used, which was introduced as a substitute for water, and not, as in most works, sewage sludge ash. In the case of the second waste, commonly used tire granules were replaced with rubber particles resulting from the fragmentation of conveyor belts. A wide range of the share of additives in the cement mortar was analyzed. The results for the rubber granulate were consistent with numerous publications. For the addition in the form of hydrated sewage sludge, the deterioration of the mechanical properties of concrete was demonstrated. It was found that the flexural strength of the concrete in which water was replaced with hydrated sewage sludge was lower than that of the sample without the addition of sludge. The compressive strength of concrete with the addition of rubber granules was higher than the control sample and did not significantly depend on the amount of granulate used.

A feasibility study of municipal solid waste leachate utilisation in concrete

Water was replaced with raw municipal solid waste leachate in a concrete mix. Compared with the control specimen (prepared with freshwater), the hardened concrete specimen made with 100% leachate and cured in freshwater for 28 days showed reductions of 20% in ultrasonic pulse velocity and 45% in unconfined compressive strength. Scanning electron microscopy revealed that an increase in leachate content increased the microscopic pores and cracks within concrete owing to organic matter in the leachate. Heavy metals are contaminants in leachate and can leak from leachate-produced concrete. The toxicity characteristic leaching procedure revealed that the heavy metal leakage of the 100% leachate specimen was lower than the maximum permissible range. Furthermore, the use of leachate in fresh cement paste induced a 56 min delay in initial setting compared with the control specimen. Slump measurements performed 0, 30 and 60 min after concrete fabrication indicated that leachate addition could double the concrete slump as compared with the control specimen. This research provides basic information for the use of raw leachate in concrete mixes. Fresh and hardened concrete properties decreased with an increase in the percentage of leachate in the mix design. Replacement of tap water with 10% leachate satisfied the US standard for ready-mixed concrete. Further investigations are recommended to approve the use of leachate as a part of concrete mixing water.

Influence of Mix Water Quality on Compressive Strength of Making Concrete

The influence of concrete mixing water quality on the compressive strength of concretes was investigated in this study. During the study, the compressive strength (CS) of the concretes was determined at 7, 14, and 28 days age. This study used 8 types of water of varying qualities as concrete mixing water (water with 71 UTN impurity level, water with 250 UTN impurity level, water with 1000 UTN impurity level, well-sourced water, acidified water, and alkaline water). Potable water was used as reference water. The results indicated that the lowest CS has been obtained by using alkaline water at a concrete age of 7 days while the usage of water with 250 UTN impurity level as a concrete mixing water yielded the highest CS. in addition, the lowest CS has been obtained when using a mixing water of alkaline at a concrete age of 14 days while the highest CS resulted from using water with 71 and 250 UTN impurities levels. Furthermore, the usage of water with 71 UTN impurities level and an acidic water as a concrete water mixing gave the lowest CS at twenty eight days concrete age, while using magnetic water and water with 250 UTN impurities as concrete mixing water resulted in the highest CS. The use of water with 250 UTN impurities as concrete mixing water favored CS development at all concrete ages. These obtained results have shown a various effects of different impurities which significantly indicate that only a few water impurities affect the concrete’s CS seriously..

A Review of Research on Mechanical Properties and Durability of Concrete Mixed with Wastewater from Ready-Mixed Concrete Plant.

The wastewater from ready-mixed concrete plants is currently being recycled as concrete mixing water. It has attracted significant attention from the construction industry and researchers since it promotes sustainable development through environmental protection, energy-saving, and emissions reduction. This article review first introduces the nature of wastewater in ready-mixed concrete plants in different regions. Then the effects of solid content in water on various properties of concrete, including working performance, durability and microscopic properties, are reviewed, respectively, when concrete is mixed with wastewater instead of tap water. Furthermore, the microscopic mechanism of action in concrete mixing with wastewater is discussed, and future work is recommended. This review provides fundamentals on the study of the properties of concrete after wastewater is mixed into concrete.

Effect of self-curing admixture on concrete properties in hot climate conditions

Hot climates prevail in many regions of the globe. The average summer temperature of hot arid areas is in the range of 40–50 °C with temperatures exceeding these values under direct solar radiation. Curing concrete in these regions may be challenging due to limited availability of suitable water for curing and/or rapid loss of curing water by evaporation. For many years self-curing admixtures were recommended as an alternative to water curing, however, limited studies have been conducted on their performance in hot weather conditions. In this investigation, the effects of a hot climate on the fresh and hardened properties of self-curing (SC) concrete and normal conventional concrete (NC) in hot weather were studied. A water-soluble polymer self-curing agent, polyethylene glycol (PEG 400), was added to the SC mixes. The testing parameters were concrete dry materials (25 or 50 °C) and/or mix water temperatures (5, 20 or 35 °C) at the time of mixing. NC samples were continuously water cured at 25 or 50 °C, whereas the SC ones were air cured at the same temperatures. The tested properties were workability, compressive strength, splitting tensile strength, and flexural strength. It was found that SC outperformed NC under varying conditions. The results could not be simply attributed to the retention of mix water by the self-curing admixture. A more comprehensive explanation for the observations is proposed.

Rheological, Mineralogical and Strength Variability of Concrete due to Construction Water Impurities

Various national and international standards recommend potable water for mixing concrete; however, the availability of potable water is virtually a daunting task in some developing communities. Concrete workers in such environments tend to utilize any available water for mixing concrete, and this may be detrimental to the quality of the concrete being produced. This study investigates the rheological, mineralogical and strength variability of concrete due to construction water impurities. Water samples were collected from four different construction sites within Southwestern region of Nigeria for production of concrete. The physical and chemical properties of the waters were determined so as to measure their rate of contamination, prior to their use for mixing concrete. The rheological properties of the fresh concrete, compressive strength, split tensile strength, and microscale features of hardened concrete, that were produced with each water sample were determined. From the results, the rheological features of concrete were found not to be affected by water impurities, however, the mechanical test results revealed about 10% reduction in strength between concrete made with water having least and higher concentration of impurities. Also, it was evident from the microscale tests that the water impurities do alter the hydration rate of concrete, which results in strength reduction. The study suggests pretreatment of concrete mixing water before use in order to avoid its damaging effect on concrete life.

Investigating the effects of bacterial activity on compressive strength and durability of natural lightweight aggregate concrete reinforced with steel fibers

The present study investigated the effects of a specific strain of Bacillus subtilis introduced into natural lightweight aggregate concrete (LWAC) as a new approach on its water absorption, electrical resistance, compressive strength, chloride ion penetration, carbonation depth, water penetration depth, and compressive strength in a sulfate environment. For this purpose, specimens of two general groups were made: with and without bacteria. Two mix designs were also used to cast specimens with and without reinforcing steel fibers. The bacterial concentration in the concrete mix water was 107 cells.ml−1. Finally, the specimens were cured in the three different environments of plain water, urea-calcium lactate solution, and nutrient solution. Overall, 252 specimens were cast each with 2 replicates. Test results revealed that, compared to normal specimens, those containing bacteria in their mix water and cured in the calcium lactate environment, recorded decreases of about 13.1%, 20.5%, 27.2%, and 44.3%, respectively, in their water absorption, chloride penetration, carbonation depth, and water penetration depth while their electrical resistance increased by about 103.6%. Moreover, in this study additional specimens containing bacterial spores, due to their dormant state and sustainability in the alkaline environment of concrete, were also cast to compare the two types of specimens in terms of their water absorption, electrical resistance, and compressive strength. The results of this study showed that incorporating the bacterial treatment method in natural LWAC mixture reinforced with steel fibers reduces not only the high dead load and cracking potential of concrete elements but also their water absorption and chloride ion penetration due to the occlusion of fine cracks.

T Ikatan Baja Tulangan Pada Beton Pond Ash Sebagai Pengganti Sebagian Pasir

Pond ash concrete bond is expected to increase bond strength, because in previous studies pond ash concrete resulted in increased mechanical properties of concrete. Bond strength is the bonding mechanism between steel reinforcement and concrete in reinforced concrete construction as the main tool to transfer internal strength between reinforcement and concrete. In this study, a total of thirty-six cylinder concrete with a diameter of 15 cm and a height of 30 cm. Variations of the test parameters are three reinforcement diameters of 12 mm, 16 mm and 25 mm and two types of reinforcement namely plain reinforcement and deform reinforcement for normal concrete and pond ash concrete, using a 25 MPa normal concrete mix design and water cement ratio of 0.52. The results showed that the increase in bond strength on the plain reinforcement from 84.49 kg/cm2 to 91.33 kg/cm2 an increase of 8.09%, while for deform reinforcement there was in increase from 119.70 kg/cm2 in concrete normal to 131.32 kg/cm2 an increase of 9.71% in pond ash concrete. Split collapse occurs in deform reinforcement, whereas in plain reinforcement, slip collapse occurs.

An Applicability of Seawater as Concrete Mixing Water

An Applicability of Seawater as Concrete Mixing Water

Neural model of projecting flexural strength of cement concrete intended for airfield pavements

This work present to the mathematical model in the form of Artificial Neural Network (ANN), intended for projecting concrete flexural strength. Input data was classified according to the type of component material and its content in concrete mix (cement contents, coarse aggregate, fine aggregate, water and admixtures). In order to determine mathematical model, a multilayer, one-way perceptron network was used, recursion network with sigmoidal neurons. The model assumes that neurons are gathered in some layers (one input layer, hidden layers and one output layer). The conducted cross-section of the impact of variable parameters values (learning constant α and momentum values η) on the accuracy of representation of flexural strength was analyses. Assessment criterion was assumed as consideration the lowest mistake level and 100% compliance. According to the obtained results ANN was assumed to be the best representing network for constant value of momentum 0.3, learning constant of 0.04 and 9 neurons in a hidden layer. Very good coincidence of component models with experiment results was achieved. At testing stage, the coincidence was achieved at the level of 99.25%, in case of the assumed network structure. During model verification by means of experimental results, the average coincidence was 99.68%.

Experimental and numerical analysis of large-scale bamboo-reinforced concrete beams containing crushed sand

Of many fast growing grasses around the world, bamboo has been persistently investigated as a possible reinforcing element in concrete. In addition to the existing knowledge on the subject, this study has performed an experimental and numerical analysis of flexural behaviour of large-scale bamboo-reinforced concrete beams containing crushed sand. The crushed sand was used as complete replacement of natural river sand at 0 and 100%, while bamboo was substituted for steel reinforcement bars at 50 and 100%. Other concrete ingredients cement, granite, and mixing water were kept constant. Curing of hardened beams was by immersion in water for 28, 56, and 84 days’ regimes. Finite element/numerical modelling and analysis of beams was performed using ABAQUS software. A nonlinear model analysis with static loading was considered with a predefined 3D model. The concrete fracture pattern was smeared crack, in the mode I. The results showed that a partial (50%) or total (100%) replacement of steel with bamboo and total replacement of natural river sand with crushed sand gave somewhat similar performance in flexure as the control beams. As expected, steel-reinforced beams were better in terms of strength across all curing regimes; however, members reinforced with 50% bamboo, although with about 14% lesser strength but having minimal deformation and crack propagation, can also be a sustainable alternative for construction. Overall, the results somewhat validate the obtained experimental flexural strength of the beams.

Effects of Polypropylene Fiber Content on Strength and Workability Properties of Concrete

Low tensile strength of plain concrete is due to the inherent presence of microcracks due to drying shrinkage occurrences or other causes of volume changes in concrete. The addition of a proper amount of fibers to concrete would act as crack arrester thus improves its static or dynamic properties. In this paper, the concrete with different amount of polypropylene fiber was investigating to find out the fibers effect on its fresh and mature properties. A plain concrete mix (reference mix) prepared for comparison purposes. Nine concrete mixes were prepared with different fiber volume fraction (FVF) ranging from 0.06% to 2.16%. It has been found out that the fiber content of the concrete mix will increase compressive, splitting, and flexural strengths of the concrete at the age of 28 days. The strengths increased and reached their maximum value at a corresponding (FVF) of about 0.36%. In comparison with the reference mix, the increase in the maximum compressive strength was about 18%, while the increase in maximum splitting tensile strength was about 16% and the increase in flexural strength was about 14%. When the fiber content increased beyond the mentioned 0.36% volume fraction: The concrete strengths started to decrease due to high volume fiber interface with the cohesiveness of the concrete matrix causing difficulty in concrete compaction with lowering its workability. At fiber (FVF) of 0.96%, the concrete slump value became zero. Thus, forced vibration needed for the compaction. For each mature concrete mix density and water absorption percentage were measured. It has been noticed that with an increase of fiber dosage in the concrete mix its density will decrease leading to contrarily an increase in the water absorption percentage. This was due to an increase in air void in the concrete due to the reduction in the workability of the concrete.

Using Calcined Waste Eggshells to Remove Sulfate in Nonpotable Concrete Mixing Water

AbstractThe experimental and theoretical potential of using calcined waste eggshells (CWEs) to remove sulfate from sulfate-laden concrete mixing water was investigated in this work. Waste eggshells...