Effect of Superplasticizers to Enhance the Properties of Concrete (original) (raw)
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Evaluation of the superplasticizer effect on the workability and strength of concrete
2020
The adverse effects of temperature on the properties of fresh concrete include increased water demand, shorter setting time and increased slump loss. Superplasticizer (SP) is important for enhancing the workability and setting time of concrete in hot weather. Hence, an expe-ri-mental investigation was conducted to determine the optimum dosage of an admixture and to study the effect of over dosing this ad-mixture. Concrete mixes with SP dosages of 0.8%, 1% and 1.2% by weight of cement were prepared along with a control mix (wa-ter/cement ratio of 0.55). After casting, the concrete samples underwent normal curing. Among the properties of fresh concrete determined were compressive strength as well as workability. The over dosage of SP appeared to degrade the properties of concrete with an indication of lower compres-sive strength. However, if the dosage levels are lower than the optimum dosage, raising the admixture dosage might help enhance the concrete characteristics.
Effect of Superplasticizer Dosage on Workability and Strength Characteristics of Concrete
The use of chemical admixtures in concrete is a common solution to achieve full compaction particularly where reinforcement congestion and shortage of skilled workers. The past researchers have been underscored the use of chemical admixtures imparts the desirable properties to concrete in both fresh and hardened state. This paper has been made an attempt to study the influence of superplasticizer dose of 400ml, 600ml, 800ml, 1000ml and 1200ml/100 kg of cement on performance of Concrete. The experimental tests for fresh and hardened properties of concrete for three mixes of 30 MPa grade are studied and the results are compared with normal concrete. The tests considered for study are, slump test, slump loss, flow table and compressive strength test The results show that for the constant water cement ratio, increase of superplasticizer dose in properties of concrete leads to gain of good workability. Moreover, there is also increase in compressive strength than that of normal concrete mix.
Influence of Superplasticizer on Strength of Concrete
This paper outlines an experimental study that measures the effects of superplasticizer admixture on proprieties of concrete. However, Superplasticizers are the most important admixtures enhancing concrete performance. The development of new superplasticizers during the last decades has determined the most important progress in the field of concrete structures. Hence, an experimental investigation was conducted to determine the optimum dosage for the admixtures and to study the effect of over dosage of the mentioned admixtures. Concrete mixes with SP dosages of 600, 800, 1000 and 1200 ml/100kg of cement were prepared, together with one control mixes. After casting, normal curing was carried out on the concrete samples. Properties such as compressive strength were determined, besides determining the workability of the fresh concrete. However, compressive strength is improved by dosage 1.0 % of SP after 28 days curing is 55 N/mm 2 , which is higher than that of control concrete, the optimum amount of admixture must be 1 %. Over dosage of SP found to deteriorate the properties of concrete with indication of lower compressive strength. However, if the dosage levels are lower than the optimum dosage, increase in admixture dosage might help to enhance the concrete characteristics.
Effect of Superplasticizer on Fresh and Hardened Properties of Concrete
In recent years, significant attention has been given to use superplasticizer as a chemical admixture on concrete. However, the use of chemical admixtures in concrete is a common solution to achieve high performance concrete. The past researchers have been underscored the use of chemical admixtures imparts the desirable properties to concrete in both fresh and hardened state. This paper has been made an attempt to study the influence of superplasticizer dose of 0.6, 0.8, 1.2, 1.8 and 2.5 percentage on performance of concrete. The experimental tests for fresh and hardened properties of concrete for M35 grade are studied and the results are compared with normal concrete. The tests considered for study are, slump test and compressive strength test The results show that the increase of superplasticizer dose in concrete leads to gain of good ability in addition to slump. Moreover, there is also slightly increase in compressive strength than that of normal concrete.
2020
Concrete is the most common building material that is used prominently in construction industry. It can be cast in any desired shape and fashion and should be workable whether on-site or in ready mix concrete production. To achieve better performance and desired proprieties of concrete, the use of chemical admixtures is priceless choice in concrete production. While, there are common problems facing to optimize superplasticzer dosage with various types of cement to produce desirable properties of fresh and hardened concrete due to lack of practices in construction industry in our country. The purpose of this research was determining optimum Superplasticizer dosage for desired workability using Marsh Cone Test at predetermined water cement ratio. It was also analysis the effect and influences of Superplasticizer dosage on concrete properties. Slump Cone test and testing machine were used to determine such properties of concrete. The first conclusion that was drawn from the research was deciding optimum dosage on cement slurry which was prepared using different types of Super plasticizer and Cements for variable water cement ratio. Secondly, the test were carried out to see effects of Superplasticizer dosage on improvement of workability and flowablity of fresh concrete in specified doses. Also, it was also noticed changes of hardened concrete properties using mechanical tests. Using 0.45 and 0.40 water-cement ratio, optimum dosage of Superplasticizer (ODS) has found out, with respect to different Superplasticzers on different brand of cement paste mix. Secondly, it also observed the effect of superplasticzer dosage for predetermined quantity (0.5%, 1.0%, 1.5% and 2.0%) on hardened concrete strength in addition to fresh concrete characteristics. Thirdly, the demand of water reduced by 20%, 23%, 27% and 30% from total mix water using 0.5%,1.0%,1.5% and 2.0% of Superplasticizer respectively in concrete mix. Generally, Superplasticzer is playing vitally role to achieve better physical properties and quality of concrete, and resolving challenges in undesirable conditions during concrete work operations. Despite these facts, over dosage of SP were found to deteriorate the properties of concrete with indication of lower compressive strength and higher porosity due to bleeding and segregation occurrences.
Effects of Superplasticizers on Fresh and Hardened Portland Cement Concrete Characteristics
Journal Article, 2016
Superplasticizer or high-range water reducer is a specific type of admixtures that is used to produce low water-cement ratio high-strength concrete with normal or enhanced workability. Therefore, by using superplasticizers, it became easier for contractors nowadays to place highly workable, durable, pumpable concrete with higher strength, and even with less cost than using other ways to produce concrete with such properties. The effects of superplasticizers on physical properties of hardened and fresh concrete have been studied in this paper by using different dosages of superplasticizer. The compressive strength tests were conducted for concrete samples of different dosages at 7 days and 28 days to determine the properties of hardened concrete, while the slump tests were conducted to determine the properties of fresh concrete as well. The results show that the highest compressive strength at 28 days was achieved at 3% dosage of superplasticizer, while the highest compressive strength at 7days achieved at 1% dosage. Whereas, using higher dosage of superplasticizer resulted in a lower compressive strength with very high slump value.
Effect of Admixtures on Concrete and Superplasticizers on Cementitious Material
International Journal for Research in Applied Science and Engineering Technology (IJRASET), 2021
Use of chemical and mineral admixtures have proved beneficial in improving quality, workability and have enhanced finish ability of concrete. They also help in maintaining the concrete during its important stages such as mixing, transporting, placing, curing and also in adverse weather conditions. Superplasticizers are super water reducers that allow 15-20% water reducion thereby increasing the workability without any change in the composition of mix.The reduction in water and cement reduces creep, shrinkage and heat of hydration. In this paper effect of different chemical and mineral admixture was studied along with sand to aggregate volume ratio ,cement content and water were analysed by preparing different concrete mixtures using water reducers and superplasticizers. A specimen of 200mm and 300mm was prepared and tested for compressive strength, split tensile strength and young's modulus. Slump test was also performed at 15 min interval. Also superplasticizers (TJ III , LIGNIN-SULPHONATE-based and NAPHTHALENE-SULPHONATE-based) were taken and their effect on the heat of hydration and induction period of cementitious material (portland cement) was studied.
Effects of Different Superplasticizers on Early Strength of Concrete
Synopsis: Four types of superplasticizers which have different functional groups and dispersion mechanisms were used in concrete mixture and cement mortar. One of them is a new generation of superplasticizer whose dispersion mechanism is by electric repulsion and steric hindrance, others have electric repulsion only. These superplasticizers were used to compare the mechanical properties and permeability resistance. The superplasticizer dosages (ranging from 0.6 to 1.5 percent, expressed as dry mass of superplasticizer per mass of cement ) were selected to produce concretes having different slumps at the same W/C . Compressive strength, flexural strength of mortar, penetration resistance, water permeability of concrete were tested. In addition, at the same W/C cement mortars have been prepared to compare mechanical properties. SEM (Scanning Electron Microscope) photos have been taken on the samples of concrete and cement mortars to obtain knowledge about their microstructures.
Cement and Concrete Composites, 2005
The use of superplasticizers in concrete manufacture was a milestone in the history of concrete, and this played a central role in the development of high strength and performance concrete. Superplasticizers are admixtures, which are added to concrete mixture in very small dosages. Their addition results in significant increase of the workability of the mixture, in reduction of water/cement ratio or even of cement quantity. Their performance depends on the type of the superplasticizer, the composition of the concrete mixture, the time of addition and the temperature conditions during mixing and concreting. Measurements of workability, slump loss, air content, as well as of strength development have been made to reach a conclusion about superplasticizers performance with the use of two kinds of aggregate: one natural (river) and one crushed limestone. Apart from this, it seems that the quantity of fines in a mixture influences the performance of superplasticizers.