Concrete Water Research Articles

Feasibility of using bio-enzyme as an admixture in reactive powder concrete

Utilizing bio-based elements as cement additives has a significant impact on the production of extremely durable and sustainable concrete composites. In the present research work, the effect of a bio-enzyme (Terrazyme) on the strength, durability, and microstructure of RPC was researched at various proportions of Terrazyme (TZ) as binder replacement (0, 0.5, 1, 1.5, 2, and 2.5%). The migration of water and transport properties of concrete are accessed through measurement of the water absorption and gas permeability. Results show that the use of TZ in RPC slightly reduced the compressive strength, and the reduction was more significant at high replacement levels when subjected to water curing. A significant reduction in the permeability of RPC with a relatively low permeability coefficient is obtained even at higher dosages of TZ in autoclaved RPC specimens with greater mechanical strength. In addition, greater chloride penetration with the prolongation of ages is obtained. The inclusion of TZ can not only enhance the waterproofing and penetration resistance of RPC but also achieve economic and ecological benefits.

Behavior of Magnetic Self-Compacting Polypropylene Fiber-Reinforced Concrete

This paper aims to produce a new concrete that combines the benefits of self-compacting concrete (SCC), polypropylene fiber (PPF), and magnetic water (MW). Slump flow, L-box, V-funnel, compressive strength, split tensile strength, and flexural strength approaches were performed to investigate the fresh properties and mechanical behavior of concrete. Various percentages (0.4%–1.2%) of self-compacted agent (SCA) and different percentages (0%–0.5%) of PPF by weight of cement were adopted. The results showed that 0.8% SCA magnetized concrete had very similar fresh properties to 1.2% SCA nonmagnetized concrete. This led the author to believe that using MW as an alternative to ordinary tap water in the manufacture of SCC has promising benefits, the most important of which is reducing the used dosage of SCA by approximately 33.3% (from 1.2% to 0.8%), resulting in a lower cost of production of such type of concrete while retaining the same workability. The optimum percentage of PPF to be used in magnetic and nonmagnetic self-compacting concrete is 0.35%.

Spiral tube solar water heating computational analysis with concrete absorber: A CFD approach

Solar collectors with concrete absorber provide structural, aesthetic, and economic advantages over existing common technology. An inexpensive concrete solar collector is being considered to improve the efficiency of solar water heaters (SWH). This work mainly focuses on the analysis of the compact concrete absorbers for water heating purpose with the spiral tube arrangement using solar energy. Concrete absorbers that use straight tubes, while less performance, they are possibly more cost-effective than traditional flat-plate collectors. The flow analysis is to be evaluated ranged between 0.005 and 0.01 kg/s for various water flow rates on the inside of the spiral tube. Furthermore, it is anticipated how the temperature of the water at the exit and storage will behave in respect to solar radiation. A finite volume package ANSYS FLUENT 15 is used to investigate the characteristics of the flow over a SWH's duct. At the lowest mass flow rate, it is discovered that the typical concrete and sand absorber water temperatures are 70 °C and 75 °C, respectively.

Parallel Bar Compressive Strength Model for Pumice Concrete Considering Frost-Heave Stress

Pumice concrete is a lightweight porous building material. Under the continuous low temperature in permafrost regions, the interstitial water of concrete is frozen, which can improve its mechanical properties. In this research, the interstitial water freezing law of pumice concrete is obtained by nuclear magnetic resonance, the frozen-heave stress and compressive strength of pumice concrete under a low-temperature environment are tested, and the relationship among the three is studied. A compressive strength model for pumice concrete considering frost-heave stress is also established using parallel bar theory. Finally, the hydrothermal coupling frost-heave model of concrete is established. Results showed that in the rapid change stage of 0°C to −10°C, the interstitial water with the largest proportion of medium pores (0.1–1 μm) in this temperature range is rapidly frozen and expanded, which makes the frost-heave stress and compressive strength increase rapidly. The frost-heave stress caused by pore-water freezing can be regarded as prestressing force against external load, which is the main reason for the increase in low-temperature compressive strength of pumice concrete. The maximum error between the calculated value of the parallel bar compressive strength model and the experimental value was 7.42%, indicating that the model has good accuracy and certain rationality. The hydrothermal coupling model can reflect the frost-heave process of concrete, and the error between the simulated and experimental values of frost heaving strain was small, which proves that the model has high accuracy.

Influence of Aeolian Sand on Capillary Water Absorption of Concrete Under Freeze–Thaw Conditions

Aeolian sand (AS) can become a green resource for concrete after the reasonable utilization. Study the evolution of AS concrete (ASC) capillary water absorption (CWA) under freeze–thaw (FT) conditions is of great significance for its popularization and application. One-dimensional (1D) CWA test was performed to analyze the effects of AS and freeze–thaw cycling (FTC) on concrete water absorption characteristics. Pore relative saturation (PRS) and pore saturation were defined to reveal the influence mechanism of AS content on concrete water absorption under FT conditions and predict the moisture distribution in damaged ASC combining with the capillary mechanics theory. The results showed that concrete frost resistance increased with increased AS content and the optimal frost resistance achieved with 100% AS replacement despite its low strength. The initial water absorption rate (WAR), pore saturation, and saturation speed of the ASC decreased with increased AS, while the PRS increased with low AS content but decreased with excessive AS. The water absorption depth increased with increased mass and dynamic elastic modulus loss rates. The mechanism regarding why excessive AS improved concrete frost resistance lay in its internal pore structure and large pore ratio, which reduced pore content that can easily absorb water, enclosed a higher volume of air bubbles, and easily formed "air locking," thereby increasing water transmission resistance and forming long transmission paths during the process of CWA.

The performance optimization of concrete bricks using a sagu fiber

Sagu (sinonggi/kapurung) is a typical food of the Tolaki ethnic group. Sagu (Metroxylon sagu rottb) is an endemic plant in Southeast Sulawesi Province. So far, sagu waste in the form of fibers (sagu fiber) has not been optimally utilized. Sagu fiber waste is only left to mount; some are dumped into the river, so it is feared that it could pollute the environment. Through innovation in reducing waste in the principles of sustainable construction, sagu fiber will be used as an added material to manufacture concrete brick wall pairs. This study aimed to test the compressive strength and water absorption capacity of sagu fiber concrete bricks with variations of 0%, 50%, 60%, and 70% sagu fiber under the sand. This study uses an experimental method with stages such as preparing work tools and work materials, making test objects, and testing. Data were analyzed using mathematical formulas for the compressive strength of concrete bricks and water absorption capacity, compared with SNI 3-0349-1989 for solid concrete bricks, and analyzed comparatively. Based on the test results in this research laboratory, it is concluded that a balanced composition to get good quality is found in 70% sagu fiber and 30% sand.

Effect of the Concrete Slurry Waste Ratio on Supercritical CO2 Sequestration.

To prevent drastic climate changes due to global warming, it is necessary to transition to a carbon-neutral society by reducing greenhouse gas emissions in all industrial sectors. This study aimed to develop carbon utilization sequestration technology that uses the concrete slurry water generated during the production of concrete as a new CO2 sink to reduce CO2 emissions from the cement industry. This was achieved by performing supercritical CO2 carbonation by varying the concrete slurry waste (CSW) ratio. The study's results confirmed that, according to the CSW ratio (5 to 25%), complete carbonation occurred within only 10 min of the reaction at 40 °C and 100 bar.

Investigation of effect of mixing procedure and alkaline solution to binder ratio on the strength of geopolymer concrete

This paper presents research on the influence of mixing and adding extra water on the strength of geopolymer concrete blended with 10% of 43-grade OPC. Two mixing methods were investigated. NaOH flakes were added in the first method; during dry mixing, heat generated by NaOH - water reaction was used to accelerate the setting time of OPC and geopolymerisation reaction. The second method was adding NaOH solution of molarity 12 M prepared 24 h before mixing concrete. In the first method, the heat generated was insufficient, and increased molarity was needed to achieve the required heat, which proved uneconomical and unsafe for the user. Also, the compressive strength of concrete prepared by adding NaOH flakes was noted to be lower than that of concrete prepared with the addition of NaOH solution. The addition of extra water in concrete was also investigated by considering two different water-to-binder ratios. During experiments, the water-to-binder ratio was initially established as 0.25 so that excess water obtained from the mix design is assumed to be utilized by OPC, making both the water-cement ratio and water-binder ratio 0.25. And again, the water-to-binder ratio was established as 0.7 to avoid extra water in the mix design. It was observed that geopolymer concrete without extra water increased its initial strength more than geopolymer concrete with extra water. But the 28th day strength of both the concrete was observed to be almost the same. It is concluded that the mixing method and extra water influence the early gain of strength and cost of concrete.

A feasibility assessment on the use of industrial waste jarosite in concrete construction

The creation of industrial byproducts has expanded dramatically with rising industrialization. The methods used in manufacturing produce a wide range of waste products. One of the by-products of the zinc manufacturing process is jarosite, and because it contains a number of harmful components such iron oxide, nickel oxide, arsenic oxide, and lead oxide, its disposal is a significant concern. The building business needs to change from being a consumption-based one to a sustainable and environmentally friendly one. In order to design and create cement concrete and other composites, jarosite is highly helpful. This review study offers a thorough and in-depth analysis of the jarosite waste's physical and chemical characteristics. Additionally, covered are the mineralogical and microstructural characteristics of the cement concrete which is prepared with the jarosite, as well as the tensile and compressive strengths, characteristics of leachate, chlorine resistance, sulphate resistance, permeability, and absorption of water of the fresh concrete that contains jarosite.

Utilization of Recovered Aggregate and Sludge Water in Ready-Mixed Concrete

Utilization of Recovered Aggregate and Sludge Water in Ready-Mixed Concrete

Seismic risk assessment of on-ground concrete cylindrical water tanks

Seismic risk assessment of on-ground concrete cylindrical water tanks

Analysis of a Composite Admixture Based on Ready-Mixed Concrete Waste Residuals

Reasonable treatment and utilization of waste residuals discharged during the production of ready-mixed concrete is an important problem in the cement industry. In this study, a composite admixture was prepared by using ready-mixed concrete waste residuals, furnace slag, and water granulated slag. The grinding characteristics of such material were investigated. Moreover, the effect of such admixture on cement hydration and pore structure was analyzed by X-ray diffraction, thermogravimetric-differential scanning calorimetry, scanning electron microcopy and mercury intrusion porosimetry. As shown by the results: The grinding characteristics of the waste residuals can be improved significantly by mixing them with furnace slag and water granulated slag. Furthermore, the composite admixture does not change the composition of hydration products; rather it contributes to refine the pore structure of the matrix, thus improving the mechanical properties of these cement-based materials.

РАЗРАБОТКА КОМПЛЕКСНОЙ ДОБАВКИ ДЛЯ ПРОИЗВОДСТВА БУРОНАБИВНЫХ СВАЙ

The article presents the results of the effect of the additive on water resistance, frost resistance and workability, which are one of the main indicators of the physical and mechanical properties of concrete. In the presented work the authors used a complex additive containing alkali (caustic soda), post-alcohol bard and hardening regulator (gypsum) in different % ratios. It is shown that the use of a complex additive in the composition of concrete significantly increases the water resistance and frost resistance compared with the control samples. The influence of the complex additive on the workability of concrete mixture has been studied. It has been established that the complex additive allows obtaining highly workable concrete mixtures and reducing their water separation, providing high preservation of concrete mixtures. The water impermeability of concrete is also significantly improved - the water impermeability grade increases by 4 steps in comparison with the concrete without additive. The proposed method speeds up the process of determining the concrete water impermeability grade and allows you to determine the water resistance grade and the degree of permeability of concrete on the basis of the obtained dependencies. When adding a complex additive in an amount of up to 7 % of the weight of cement increases the brand on frost resistance. It is found that the concrete with the studied complex additive has high physical and mechanical properties. The optimum dosages of the considered additive were found and used in the present work.

Rubber micro granules affect water absorption and compress the strength of concrete composite

End-of-Life cars and trucks Tyres (ELT) are still an environmental issue around the world and in Latvia. The addition of rubber additives into concrete is quite well-studied worldwide. It is known that the introduction of rubber crumb in large quantities (> 5 % by volume) reduces the mechanical strength of the material and the modulus of elasticity. The results have shown us differences between rubber crumb practical size, and the amount of admixture in concrete. Achieved results clearly showed us the difference between shredded rubber micro granules and disintegrated-like admixture particles to achieve the composite concrete water absorption differences in 0,6 % but compress strength in greater diapason.

СТРУКТУРООБРАЗОВАНИЕ И ПОТРЕБИТЕЛЬСКИЕ СВОЙСТВА ГРАНУЛИРОВАННЫХ АСФАЛЬТОБЕТОННЫХ СМЕСЕЙ С ВКЛЮЧЕНИЕМ ФОСФОГИПСА И ВТОРИЧНОГО ПОЛИЭТИЛЕНТЕРЕФТАЛАТА

The effects of structure formation in disperse systems obtained by pelletizing in the manufacture of asphalt concrete mixtures with the inclusion of up to 30% phosphogypsum have been considered. In studying the physical-chemical and consumer properties of bitumen with polyethylene terephthalate additive they used the method of measuring the wetting edge angle. Microphotographs of modified binder make it possible to judge about the change of bitumen surface state. Thermal effects occurring as a result of modifying properties of such materials were registered. It was found that production of asphalt-concrete mixture by pelletizing provides high indicators of compressive strength of the hardened material. We found an increase in asphalt concrete water resistance at simultaneous introduction of polyethylene terephthalate and industrial waste phosphogypsum powder into the disperse system. Synergetic effect of the above additives on the achievement of positive effect of structure formation in asphalt-binding materials has been revealed, which reveals new prospects for their use in the production of construction works.

Application of the UNDBE Model in Combination with the RALG Method to Solve the Problem of Radioecology of Water Bodies

Introduction. The presence of radioactive pollution releases into the aquatic environment of NPPs operating in the normal mode, as well as during various emergency situations, requires the use of means for predicting the impact of such releases on the condition of surface water bodies. The existing developments either do not have a sufficient accuracy or are complicated and require a large amount of initial data and knowledge of the exact values of the parameters of the running processes. To ensure accuracy of forecasting pollutants spreading in surface water under conditions of limited measuring and computing facilities a box model (UNDBE) of pollution transfer was developed taking into account the time of pollution transportation through the water body and dilution of pollution in the incomplete box volume. The method of model adjustment according to measurement data has been developed, which additionally improves forecasting accuracy. This was made possible due to the short implementation time of the proposed model on a computer and the use of parametric identification using the RALG program. Purpose of work. Presentation of the general description of the developed model. Demonstration of modeling possibilities and parametrical identification by means of the offered model in combination with program means of search of extremum of not differentiable function. Results. In addition to a general description of the developed model, a modification for modeling tritium and strontium-90 propagation is given. The results of modeling and parametric identification are shown on examples of tritium distribution in the Loire river basin and strontium-90 in the Kiev reservoir. Conclusions. Application of UNDBE model in combination with RALG procedure provides fast calculation at preservation of modeling accuracy, possibility of fast and exact adjustment for the concrete water object that makes possible its application as an emergency response system. There is a possibility to apply the outlined approach for modeling the transport of other types of pollutants in surface water bodies. Keywords: pollution transport, surface water bodies, UNDBE box model, parametric identification, RALG experience.

Recycling of Waste Glass as Partial Replacement to Fine Aggregate and Rice Husk Ash as Partial Replacement of Cement in Concrete Production

The Recycled Waste Glass (RWG) is a most suitable substitute to the natural sand to be utilized in the concrete manufacturing industryand Rice Husk Ash (RHA) is an agricultural by-product having enormous characteristicsto utilize as cementitious material in concrete. This study was carried out to understand the effects of RHA as partial replacement to cement and RWG as a partial replacement to natural fine aggregate with 10%, 20% and 30% levels of substitutions in the concrete mixes respectively. The effects were investigated on the workability and compressive strength characteristics of fresh and hardened concrete. A total of 4 mixtures were prepared for M15 grade concrete with 1:2:4 concrete proportions and water to cement ratio of 0.55. Out of them one was controlled mixture and three were with 10%, 20% and 30% equal substitution levels of combined RHA and RWG. The acquired results showed that the slump values were like that of conventional concrete at combined incorporation of RHA and RWG at 10% replacement, but a decline was noticed at 20% and 30% replacement. The decline was due to the more surface area of RHA which absorbs more water. The compressive strength at 10%RHA and 10% RWG combined replacement in concrete mix was increased by 9.7% as compared to controlled mix after 28 days curing. The results were similar at 20%RHA and 20%RWG incorporation as compared to controlled concrete mix. It is concluded that RHA and RGW can be utilized at 10% equal replacement in the concrete and the cost of construction can be reduced. This research work will be helpful in developing a comprehensive scientific data base on combined utilization of RHA and RWG in the concrete mixes and the upcoming scientists, scholars and students will be benefitted.

Assessing Fresh Concrete Performance and Water Absorption Characteristics of Concrete with Partially Replaced Broken Tiles

A number of research seeking alternative materials to augment normal coarse aggregate to reduce overreliance on granite while saving the environment is on the rise. This study assessed the workability, water absorption and density of concrete with waste ceramic tiles as partial replacement for crushed granite coarse aggregate. Crushed waste ceramic tiles from ceramic manufacturing industries and construction sites were blended with crushed granite for concrete production. A mix ratio 1: 1.11: 2.72 (cement: sand: coarse) for nominal C30 concrete was produced with (0, 10, 20, 30, 40, 50 and 100) percent volume ceramic waste replacement for crushed granite at constant water-cement ratio of 0.5 to produce concrete cubes and cured for 7 and 28 days. Tests conducted revealed concrete workability and density decreased with increasing ceramic waste while water absorption increased with increasing ceramic waste but not above acceptable limits. However, use of waste ceramic tiles as partial replacement for crushed granite in concrete is encouraged, but not exceeding 20% maximum for structural concrete. This mode of recycling ceramic waste could positively promote green construction for sustained environment; hence, it should be encouraged with conditional limitation and further research of its use.

Rice Husk Ash in Concrete

This study conducted an extensive literature review on rice husk ash (RHA), with a focus on its particle properties and their effects on the fresh, mechanical, and durability properties of concrete when used as a partial cement replacement. The pozzolanic property of RHA is determined by its amorphous silica content, specific surface area, and particle fineness, which can be improved by using controlled combustion and grinding for use in concrete. RHA particle microstructures are typically irregular in shape, with porous structures on the surface, non-uniform in dispersion, and discrete throughout. Because RHA has a finer particle size than cement, the RHA blended cement concrete performs well in terms of fresh properties (workability, consistency, and setting time). Due to the involvement of amorphous silica reactions, the mechanical properties (compressive, tensile, and flexural strength) of RHA-containing concrete increase with increasing RHA content up to a certain optimum level. Furthermore, the use of RHA improved the durability properties of concrete (water absorption, chloride resistance, corrosion resistance, and sulphate resistance). RHA has the potential to replace cement by up to 10% to 20% without compromising the concrete performance due to its high pozzolanic properties. The use of RHA as a partial cement replacement in concrete can thus provide additional environmental benefits, such as resource conservation and agricultural waste management, while also contributing to a circular economy in the construction industry.

Strength and microscale properties of bamboo fiber-reinforced concrete modified with natural rubber latex

Development of concrete using alternative materials has become very important in the quest to achieve sustainable development in the built environment. However, it is critical to continually modify concrete mixtures to correct deficiencies of fresh and long-term properties. In this study, natural rubber latex and bamboo fiber were added as constituent materials in concrete, and the effects of the constituents on concrete were explored. Bamboo fiber (BF) and natural rubber latex (NRL) were added in proportions of 0%, 1%, and 1.5%. The study determined the workability (slump) of fresh concrete mixes, strength, and water absorption properties of the hardened samples after curing them in water for 7, 14, and 28 days. The morphology of the concrete samples was explored using SEM-EDX equipment. The results showed that samples having 1% bamboo fiber content and 1% rubber latex had the highest compressive strength among all the presented samples. Furthermore, samples containing equal but lower percentages of both bamboo and NRL had the highest compressive strength comparable to that of the control. This research showed the feasibility of combining bamboo fiber and rubber latex for an alternative eco-friendly construction approach to enhance the performance of conventional concrete in terms of tensile strength and flexural strength properties.