Concrete Admixtures Research Articles

Effect of Addition of Rice Husk Charcoal on Concrete Compressive Strength

Along with the advancement of time, technology in the field of building construction, especially concrete manufacturing, is also experiencing very rapid development, almost every aspect of human life is always associated with concrete. The use of added materials has been done in the process of concrete admixture. Based on this, this study aimed to determine the increase in optimal compressive strength of concrete with additional material of husk charcoal and compressive strength of the plan at 28 days is 20 MPa. In this study using the percentage variation of husk charcoal 0 %, 2 %, 4 %, and 6 % by weight of cement. The analytical review of this research is the compressive strength, with concrete cylindrical specimens having a diameter of 15 cm and a height of 30 cm. The concrete mix planning method uses the Indonesian National Standard (SNI) method. The material for this experiment is rice husk which is made into charcoal by manual process. After testing and research, the results show that the use of rice husk charcoal results in reduced workability because the absorption capacity of rice husk is quite high, and the strength of concrete with the addition of husk charcoal by 2 %, 4 %, and 6 % concrete increases its strength from compressive strength concrete plans of 20 MPa. Concrete compressive strength with a mixture of 2% husk charcoal produces compressive strength of 24, 3 MPa, there is an increase of 4, 3 MPa with the addition of husk charcoal by 2 %.

Effective multifunctional additives for concrete based on the wastes of the oil industry

AbstractWe consider the issues of obtaining multifunctional additives for concretes and mortars based on waste of the fat‐and‐oil industry. The results of research on the composition and properties of tar oil distillation of fatty acids of the fat‐and‐oil industry (gossypol resin) demonstrate the possibility of their use as raw materials to obtain chemical admixtures for concrete. The necessity of the modification of waste production of vegetable oil was identified with the aim of reducing the negative impact of nonwater‐soluble fractions on structurization, which is expressed in the blocking of products of cement hydration and by reducing the potential strength of the concrete. The results of physical and chemical research on additives were obtained according to the influence of the volume of injected additives on the properties of concrete, which showed a polyfunctional effect. We have justified the technical, economic, and environmental effects of chemical additives on the basis of waste of the fat‐and‐oil industry.

Performance of concrete containing mussel shell (Perna viridis) ash under effect of sodium chloride curing

Mussel shell is a type of waste that consist large amounts of calcium content (CaCO3) (>95%). It is potentially to be used as concrete filler which can reduce porosity in concrete micro-structure (compacted concrete) and indirectly reduce quantity of water used to maintain concrete workability. This paper investigates the performance of mussel shell waste as an admixture in normal concrete. These waste were crushed using ball mill for 5 hour then sieved with 75μm sieve sizes. Five different percentages of mussel shell ash (MSA) were incorporated in concrete as an admixture 0%, 1%, 2%, 3% and 4% (S0, S1, S2, S3 and S4) base on w/c 0.5 according to DoE method with total of 90 samples. Specimens then were cured using 2.37% of sodium chloride (NaCl) solution for 7 and 28 days. Data were analysed according to physical, mechanical and its durability properties of materials and its specimens. Particle size analysis (PSD), specific gravity, SEM image and setting time are measured on MSA, OPC and samples MSA concrete included slump analysis for concrete workability. While it’s mechanical and durability properties of MSA concrete were analyses through compressive, split tensile and water capillary absorption. The result showed that increment percentages of MSA could effect on the strength of both compressive and split tensile. However, minimum percentages of MSA of 1% gained higher strength compared to control specimen. The differences between MSA percentages and its curing duration incorporated indicating an improvement while S1 and S3 indicates lower rate of capillary absorption for 7 and 28 days each. Overall, the results to establish concrete strength improvement of MSA in concrete should be limited to 1% uses. While S2 and S4 for concrete permeability and workability. With this percentages, concrete display an improvement behaviours according to its strength and durability towards sodium chloride exposure.

Macro synthetic fibre reinforced concrete: Influence of the matrix mix design on interfacial bond behavior

Since the composite nature of Fibre Reinforced Concrete materials, their performance is strictly dependent on the mechanical properties of their components, matrix and fibres, but, above all, on their interaction. The collaboration of the two materials is directly responsible of the force transferring mechanism from concrete to fibres that reflects their contribute in the residual flexural strength performance. This paper aims at understanding how the concrete admixture components might affect the bond of polypropylene crimped fibres, and presents the preliminary results of an experimental campaign consisting of pull-out and compression tests. Four water cement ratios and three cement-sand ratios were considered. The experimental analysis is also supported by the calibration of a numerical model that simulates the pull-out behaviour of a single fibre.

An Experimental Analysis of Aggressive Environment of Concrete with Ceramic Tiles and Carbon Black Powder

In the manufacturing industry among the primary producers of carbon dioxide, cement industry plays one o f the important role. Hence if we reduce the amount of usage of cement in concrete preparation, it will be helpful for a healthy environment. Upon consider the environmental pollution, in the concrete preparation mineral admixtures are used as a partial substitute for cement. Here in this paper, ultra-fine ceramic powder is using as a mineral admixture which are procured from used or broken tiles in 5%, 10% and 15% as level of replacement and also carbon black powder from rubber industry in 1% both by weight of water to made a high strength concrete of M50 grade Concrete. In severe environments like industrial and marine environments, a concrete with high strength may not perform because they are characterized by high chloride content, sulphate content or combination of both. Hence in order to provide such an environment in the laboratory, the specimens are subjected for curing in H2SO4 acid (industrial) and NaCl base (marine). To find the performance of the use of ceramic powder, black carbon powder, compressibility strength and split tensile strength, flexural strength, porosity, corrosion resistance tests are performed.

A concise review of current lignin production, applications, products and their environmental impact

Lignin is the second most abundant natural material on the earth. Commercially, it is generated as a waste product from the paper and ethanol production. The worldwide production of lignin is approximately 100 million tonnes/year valued at USD 732.7 million in 2015. It is expected to reach $913.1 million by 2025 with compound annual growth rate (CAGR) of 2.2%. Two principal categories of lignin are ligno-sulphonate (˜88%) and kraft lignins (˜9%), however a new category organosolv (˜2%) is now gaining popularity due to the production of second generation biofuels (bioethanol production). The organosolv lignin segment is expected to experience the highest growth over the coming years, at an estimated CAGR of over 5% from 2016 to 2025. Chemically lignin is a polyaromatic macromolecule. The complexity and richness of its functional groups makes it attractive for converting into a variety of value added products like high performance carbon fiber, bio-oil, vanillin, and phenolic resin to name a few. Over the years lignin has been predominantly burnt as fuel for heat and power. Less than 2% of the available lignin was sold, primarily in the formulation of dispersants, adhesives and surfactants. However, in the last decade lignin-based research and new product development has picked significant momentum due to the bio-refinery concept as aging pulp and paper mills need to diversify their products portfolio to maintain their vitality. The emerging biofuel/bioenergy technologies are working to develop value-added co-products from lignin and bio-oil as a means of making the processes more cost effective. There is a resurgence in the demand for lignin for use in binders, adhesives, bioplastics, concrete admixtures and biomedical applications. Effective “upstream” and “downstream” valorization techniques are facilitating fine tuning of lignin as a building block for high value chemicals. Other market dynamics driving lignin use are stringent regulations for dust control, demand for high quality concrete admixtures and dispersants, and carbon rich products (activated carbon, carbon filer, resins etc.). To further accelerate development of lignin based products consumer awareness and gap between research and development and consumer products need to be reduced.

Gypsum dehydration in cement and its impact on air-void structure in air-entrained concrete

The compatibility of the admixture of cement and concrete is an important factor in the creation of high-quality concrete. Common problems involving the resistance of concrete to freezing and thawing drew the authors’ attention to gypsum dehydration in cement. The influence of gypsum dehydration on the air-void structure of air-entrained concrete obtained with cement low in C3A was examined. In all studied cases, the negative influence of gypsum dehydration was observed. It is believed that greater solubility and a higher solubility rate of hemihydrate result in higher early-stage Ca2+ and SO42− ion concentrations, and thus cause alterations in the chemical admixture’s mechanism of action.

Bacterial self-healing of concrete and durability assessment

Bacterial self-healing is an innovative technology allowing repairing open micro-cracks in concrete by CaCO3 precipitation. This bio-technology improves the durability of the structure. In this paper, peptone, yeast extract and Bacillus Subtilis were added as microbial adjuvant in concrete mix design. This led to a decrease in porosity resulting in an increase of strength, dynamic modulus as well as a reduction of water uptake, gas permeability and chloride permeation. Scanning electron microscopy, energy dispersive spectroscopy and raman spectroscopy showed that the microbial precipitations in the crack were CaCO3. Moreover, the morphology of calcite crystals was a needle-like, bouquet-like and rhombohedral-shaped. At 44 days, 400 μm crack surface width was completely filled. Hence, peptone, yeast extract and Bacillus Subtilis could be considered as a promising concrete admixture in enhancing durability and mechanical properties of concrete. Furthermore it is established that Eurocode 2 could be applied with confidence for predicting properties of bacterial concrete.

Structural characteristics and cementitious behavior of basic oxygen furnace slag mud and electric arc furnace slag

Basic oxygen furnace (BOF) slag mud and electric arc furnace (EAF) slag were characterized by TG-DSC, XRD, FTIR, 27Al MAS-NMR and ICP-MS techniques to correlate structural characteristics with cementitious behavior. BOF slag mud is a by-product discharged after the wet milling and magnetic separation of basic oxygen furnace steel slag. Due to the cementitious phases of C2S and C3S have been hydrated during the wet milling process to form Ca(OH)2 and C-S-H in the BOF slag mud, the cementitious activity of BOF slag mud is much lower than that of EAF slag. Considering the higher water absorption capacity and lower contents of C2S, C3S and tetrahedrally coordinated Al in the BOF slag mud, it is thought that BOF slag mud is not suitable for being utilized as mineral admixture; while the EAF slag, exhibiting appropriate cementitious activity, can be utilized as mineral admixture in cement and concrete. Particular attention should be paid to solidify phosphorus of EAF slag to avoid retarding effect in the hydrated system of blended cement and concrete.

Global lignin products market driven by need for high-quality concrete admixtures

Global lignin products market driven by need for high-quality concrete admixtures

Comparing Properties of Concrete Containing Electric Arc Furnace Slag and Granulated Blast Furnace Slag.

For sustainable development in the construction industry, blast furnace slag has been used as a substitute for cement in concrete. In contrast, steel-making slag, the second largest by-product in the steel industry, is mostly used as a filler material in embankment construction. This is because steel-making slag has relatively low hydraulicity and a problem with volumetric expansion. However, as the quenching process of slag has improved recently and the steel making process is specifically separated, the properties of steel-making slag has also improved. In this context, there is a need to find a method for recycling steel-making slag as a more highly valued material, such as its potential use as an admixture in concrete. Therefore, in order to confirm the possibility of using electric arc furnace (EAF) oxidizing slag as a binder, a comparative assessment of the mechanical properties of concrete containing electric arc furnace oxidizing slag, steel-making slag, and granulated blast furnace (GBF) slag was performed. The initial and final setting, shrinkage, compressive and split-cylinder tensile strength of the slag concretes were measured. It was found that replacing cement with EAF oxidizing slag delayed the hydration reaction at early ages, with no significant problems in setting time, shrinkage or strength development found.

Recovering Iron from Iron Ore Tailings and Preparing Concrete Composite Admixtures

Iron ore tailings (IOTs) are a form of solid waste produced during the beneficiation process of iron ore concentrate. In this paper, iron recovery from IOTs was studied at different points during a process involving pre-concentration followed by direct reduction and magnetic separation. Then, slag-tailing concrete composite admixtures were prepared from high-silica residues. Based on the analyses of the chemical composition and crystalline phases, a pre-concentration test was developed, and a pre-concentrated concentrate (PC) with an iron grade of 36.58 wt % and a total iron recovery of 83.86 wt % was obtained from a feed iron grade of 12.61 wt %. Furthermore, the influences of various parameters on iron recovery from PC through direct reduction and magnetic separation were investigated. The optimal parameters were found to be as follows: A roasting temperature of 1250 °C, a roasting time of 50 min, and a 17.5:7.5:12.5:100 ratio of bitumite/sodium carbonate/lime/PC. Under these conditions, the iron grade of the reduced iron powder was 92.30 wt %, and the iron recovery rate was 93.96 wt %. With respect to the original IOTs, the iron recovery was 78.79 wt %. Then, highly active slag-tailing concrete composite admixtures were prepared using the high-silica residues and S75 blast furnace slag powder. When the amount of high-silica residues replacing slag was 20%, the strength of cement mortar blocks at 7 days and 28 days was 33.11 MPa and 50 MPa, respectively, whereas the activity indices were 89 and 108, respectively. Meanwhile, the fluidity rate was appropriately 109. When the content of high-silica residues replacing slag was not more than 30%, the quality of mineral admixtures was not reduced. Last but not least, reusing the high-silica residues during iron recovery enabled the complete utilization of the IOTs.

Effect of Solid Waste-Petroleum Coke Residue on the Hydration Reaction and Property of Concrete.

Taking advantage of the desulfurization petroleum coke residue obtained from circulating fluidized bed boiler technology to replace a part of cement clinker and prepare the concrete can not only reduce the production of cement clinker and related CO2 emissions, but can also improve the utilization rate and utilization level of petroleum coke waste, which has good environmental and economic benefits. In this study, through the comprehensive analysis of a compressive strength test, X-ray diffraction test, and Cl− penetration resistance test, the hydration mechanism of desulfurized petroleum coke residue in concrete is revealed, and the optimum replacement ratios of single-added petroleum coke residue, multi-added petroleum coke residue, and mineral admixtures in concrete are evaluated and proposed. The results showed that mixing the 10% petroleum coke residue and 40% blast furnace slag would be most appropriate to replace the cement in concrete, thus the effective utilization of mineral admixtures and coke residue in concrete without strength loss could be realized.

Influence of organic components and inorganic components of reed as a concrete admixture

Vegetation in closed water area improves the natural environment by providing a habitat for juvenile shellfish and fish and by facilitating the intake of nutrients by plants. For these aquatic fauna, nutrient discharge occurs as mature individuals are harvested as fishery resources. However, aquatic plants are not typically harvested, so nutrients taken up by the plants as they grow return to the water in dead vegetation. These plants will not make a sustained contribution to the purification of the overall aquatic environment unless a system is developed to harvest them. In this research, we examine how reeds can be recycled. A potential application for the reeds is in mineral/chemical concrete admixtures. Reeds are rich in inorganic silica and organic lignin, both of which are effective as concrete admixtures. Silica is typically amorphous and is used as a pozzolanic admixture to impart long-term strength to concrete. Lignin is used as a water reducer admixture, which reduces concrete water content or slows the setting rate. The silica and lignin contained in the reed were examined from the viewpoint of strength development and flow of concrete. From the viewpoint of strength development, it was confirmed that long-term strength can be expected by replacing ashes of reeds with 5% of cement. Then, to improve mortar flow, reed powder was added to mortar as a water reducer at a weight fraction of 1% and was suitable in terms of phenol concentration. The results indicate that reed can be used as a chemical and physical concrete admixture.

The Application of Sodium Acetate as Concrete Permeability-Reducing Admixtures

The study is aimed to introduce the application of sodium acetate into the concrete mix for water permeability-reducing admixtures. The sodium acetate was treated as concrete admixture by dissolving in it through the water. Three kinds of concrete strength (fc’ = 30 MPa, 40 MPa, and 50 MPa) and five mixture proportions of sodium acetate were involved to provide the specimens. To evaluate the performance of variation sodium acetate mixtures, a series of water permeability test was conducted on 28 days after concrete casting. A separate test of the temperature belongs to the concrete paste was measured in order to investigate the role of the sodium acetate solution for decreasing the temperature during the hydration process. The experiment results show a considerable reduction of water ingress for the lower concrete strength with the addition of sodium acetate greater than 3%. However, the opposite results were obtained for the highest concrete strength. A scanning electron microscope (SEM) test on the lowest strength can confirm the evolution of crystal structure inside the concrete pores.

ELABORATION OF OPTIMAL MODE FOR HEAT TREATMENT OF SHALES FOR OBTAINING METAKAOLIN

Concrete is highly energy- and material intensive building material. At the same time, the most expensive component of concrete is cement. The use of pozzolanic admixtures in cement and concrete is an effective method to reduce the consumption of clinker part of cement. In recent years, metakaolin has been very popular in the world as an effective pozzolanic admixture to cement. Addition of metakaolin makes it possible to increase density, water proofness and strength of cement. Metakaolin is received by heat treatment of kaolin clays, the deposits of which are highly limited. Therefore, studies are under way to investigate the possibility of obtaining metakaolin from ordinary polymineral clays and shales, which would be much cheaper and would make the production of this material affordable. In our experiments, to receive metakaolin were used alluvium clay shales formed as a result of mud flows. The optimal mode of heat treatment of clay shales has been elaborated, which ensures maximal presence of metakaolin. To determine the pozzolanic properties of heat-treated clay shales, cements were made in accordance of ASTM C 311–05 standard test methods for sampling and testing fly ash or natural pozzolans for use in portland cement concrete.

Effect of rice-husk-ash admixture on the strength and workability of concrete

For over two decades, rice-husk-ash has been discovered to be a highly reactive pozzolana and has been used to substitute a portion of the cement content in concrete mix in order to reduce the cost of concrete manufacture and environmental hazards posed by rice-husk in rice producing areas. This research focuses on the possibility of using rice-husk-ash as strength enhancement admixture in concrete. Rice-husk-ash was added in small percentages of 2, 4, 7, 10 and 12% to concrete mixtures. The workability was tested using slump test, while strength of the cubes after 28 days curing were obtained with a universal testing machine. The results showed that for concretes of medium workability the strength of the concrete containing RHA increased to 25% above the normal concrete of the same mix proportion at 7%. Further addition of RHA above 7% and below 10% reduced the workability very low but still good for mass concrete. Above 10%, improvement in strength ceased and the concrete became very dry. Based on the result of the tests, addition of 7% RHA by weight of cement will improve the strength of the concrete without appreciable change in the initial workability. In the case where the initial workability may be altered from medium to low workability, up to 10% RHA may be added. In other words RHA can be added to concrete mix up to 10% by weight of the cement content as long as the resulting change in the workability remains acceptable for the concreting work in question. Keywords: Rice-husk-ash, admixture, Concrete strength, Workability

Effect of water to cement ratio (w/c) and age on the ultrasonic and electrical Non-Destructive Testing (NDT) of plain and chemical admixtured concrete

The ultrasonic velocity, the electrical resistivity and the compressive strength of plain (N), accelerating admixture (A), high range water reducing admixture (H), and retarder admixture (R) concrete samples of 0.35, 0.42, 0.55 and 0.6 w/c ratios were measured, The effect of concrete age on the samples with 0.42 water to cement (w/c) ratio were studied. The results show that, the ultrasonic velocity, the electrical resistivity and the compressive strength are inversely proportional to the w/c ratio for all samples and at the same w/c ratio the values of these parameters for the high range water reducing admixture (H) concrete, are relatively higher than that of the accelerating admixture (A) concrete then the Plain (N) concrete, then, retarder admixture (R) concrete. For the samples with different ages, the results show that, the ultrasonic velocity, the electrical resistivity and the compressive strength increase rapidly at first 7 days, after that, the increment slows down significantly after 28 day, and at the same age, the values of theses parameters of the accelerating admixture concrete sample (A4) are higher than that of the other samples {high range water reducing concrete (H4), plain concrete (N4) - retarded concrete (R4)} The destructive compressive strength was correlated to the nondestructive ultrasonic velocity and electrical resistivity measurements. Linear relationships between the compressive strength and either the ultrasonic velocity or the electrical resistivity were obtained. The results were attributed to the hardening and the microstructure development in the different concrete samples

Diamidoamine Salt as the Admixture for Concrete Increasing the Resistance to the Freeze-Thaw Cycle

Concrete freeze-thaw resistance, along with compressive strength, is one of its basic features, which have a significant impact on the durability of structures of buildings and engineering structures. Numerous studies presented in domestic and foreign literature showed that there is a relationship between the concrete mix’s composition and the extent of frost damage. The frost durability of concrete depends on many factors. Therefore, cyclic changes of air temperature in winter conditions (over 100 freeze-thaw event cycles per year are estimated in Poland) must be taken into consideration as soon as in the phase of designing a concrete mix and structural elements. Proper designing of the concrete mix, optimal selecting of proportions and kinds of components, applying of appropriate kinds of additives and admixtures as well as proper maintenance of concrete can protect the investor against serious financial consequences. The paper discussed the influence of sub-zero temperatures effect on cement concretes properties. The requirements that are imposed on designers in terms of concretes resistance to frosts cyclic effect by the currently applicable standards were presented. The paper also presents the results of an original research programme showing the effectiveness of diamidoamine salt as an admixture for concretes that increases their resistance to the freeze-thaw cycle. Within the preliminary tests, the influence of the diamidoamine salt on early and 28-day compressive strength was marked. The air content in fresh concrete, absorbability and water permeability were also specified. The freeze-thaw resistance of concretes with the addition of the diamidoamine salt after 50 freeze-thaw cycles was determined. The conducted preliminary laboratory tests showed that applying the diamidoamine salt causes the decrease in compressive strength. This decrease is proportional to the admixture content. The applied admixture significantly decreases the absorbability, improves waterproofness and freeze-thaw resistance of the concrete.

Experimental Investigation of Self-Curing Concrete by Using Natural and Chemical Admixtures

Background/Objectives: To develop a self-curing concrete economically. Methods: To make self-curing concrete, natural and chemical admixture were used; samples were cured in room temperature (15-20°c) and outdoor condition (30-35°c). Firstly, samples were divided into fourteen trials with different percentage of wood powder 2%, 4%, 6%, 7% and 8% and polyethylene glycol 400 (PEG400) 0.5%, 1%, 1.5%, 2%, 2.5%. Finally, 6% wood powder was found as optimum trial and again made trials of constant percentage of wood powder (6%) with different combinations of PEG400 (0.5%, 1%, 1.5%, 2% and 2.5%) in room and outdoor temperature. The specimens were cured for 7 and 28 days. Findings: The results show that the uses of wood powder and PEG400 have positive effect on mechanical properties of concrete compared with conventional concrete. Improvements/Applications: A mix of 6% wood powder with 1.5% polyethylene glycol 400 (PEG400) is found optimum and economical for M30 grade of concrete in room temperature but for having a good strength of grade M30 of concrete considering economical point for outdoor temperature a mix of 6% wood powder with 2.5% polyethylene glycol 400 (PEG400) can be effective and optimum. Keywords: Outdoor Temperature, Polyethylene Glycol-400, Room Temperature, Self-Curing Concrete, Wood Powder