IJERT-Influence of Super Plasticizer and Time Lag on Compressive and Flexural Strength of High Performance Concrete (original) (raw)
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In recent decades, tremendous success was achieved in the advancement of chemical admixtures for Portland cement concrete. The effect of super plasticizer (SP) on the properties of fresh and hardened concrete like compressive and flexural strength is well documented. But the influence of the dosage of Super Plasticizer and time lag on the compressive and flexural strength of High Performance Concrete is yet to be determined. In this study, the effect of the dosage and time lag in placement of concrete is studied. Four grades of concrete: M20, M30, M40, M50 were chosen and cubes and beams were casted for different dosages of super plasticizer ranging from 0.5 to 1.1 percent of the cementitious material and for different time lags ranging from 0 to 4 hrs. Testing was carried out to assess the effect of the dosage of super plasticizer and the effect of time lag in the placement of concrete. The results of the experimental procedure carried out and the inference from the study are discussed.
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.
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.
Strength and Workability Characteristics of Concrete by Using Different Super Plasticizers
International Journal of Materials Engineering, 2012
Concrete, a composite material made with cement, aggregates, admixtures or super plasticizers and water comprises in quantity the largest of all man-made materials. Although aggregates make up three fourths of the volume of concrete, the active constituent of concrete is cement paste. The properties and performance of concrete are largely determined by the properties of the cement paste. Super plasticizers in concrete confer some beneficial effects such as acceleration, retardation, air entrainment, water reduction, plasticity etc., and these effects are due to their action on cement. The scientists are mainly concentrating to develop the specialized concretes, to enhance the service life of the buildings, and to provide satisfactory performance under aggressive environments. In the present experimental investigation M 30 concrete is used as control mixture with four different super plasticizers namely SNP (Sulphonated Naphthalene Polymer) 1, SNP 2, SNP 3 and SNP 4. Strength of modified concrete is compared with the normal concrete i.e. without super plasticizer. The results show that the significant improvement in the strength and workability of modified concrete.
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.
Effects of Super Plasticizing and Retarding Admixtures on Properties of Concrete
The adverse effects of elevated temperatures on the properties of the fresh concrete include increased water demand, shorter setting time and increased slump loss. Superplasticizers (SP) and retarders are important to enhance the workability and setting time of concrete under hot weather, 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 and retarder dosages of 600, 1200, 1800, and 2500 ml/100 kg of cement were prepared, together with control mix (water/cement ratio were 0.50). After casting, normal curing was carried out on the concrete samples. Properties such as compressive strength, was determined, besides determining the workability of the fresh concrete. Over dosage of SP or retarder were 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.
The adverse effects of elevated temperatures on the properties of the fresh concrete include increased water demand, shorter setting time and increased slump loss. Superplasticizer (SP) is important to enhance the workability and setting time of concrete under hot weather, hence, an experimental investigation was conducted to determine the effect of dosage of the mentioned admixture. Concrete mixes with SP dosages of 400, 600, 800, 1000 and 1200 ml/100kg of cement were prepared, together with two control mixes (water/cement ratio were 0.56 and 0.66 respectively). After casting, normal curing was carried out on the concrete samples. Properties such as compressive strength, porosity, water absorption, permeability and initial surface absorption were determined, besides determining the workability and setting time of the fresh concrete. Over dosage of SP were found to deteriorate the properties of concrete with indication of lower compressive strength and higher porosity. 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.
EFFECTS OF CHEMICALS AS SUPERPLASTICIZER ON VARIOUS PROPERTIES OF THE CONCRETE
International Journal of Creative Research Thoughts (IJCRT), 2020
The second most consumed material on earth is concrete, after water. So we need to look for ways to reduce the use of water in concrete in most economic way possible. We also want concrete to gain its ultimate strength earlier to reduce the overall requirement of water. Plasticizers and Superplasticizers are used to reduce the water requirement in the concrete. The use of these admixtures not only reduces the water content of the concrete but also gives higher early strengths and higher ultimate strengths. The available Plasticizers and Superplasticizers in the market are costly and hence cannot be used for smaller project as they will make the project uneconomical. This project work is conducted to find better alternatives to these available costly Superplasticizers. This report is about the project work which includes the study of effect of chemicals as Superplasticizers on various properties of the concrete. The study of different chemicals used as Superplasticizers for concrete and their comparison with the normal concrete. There are two different chemicals taken for the project work. The chemicals are added in different proportions of 0.25%, 0.5%, 0.75% and 1% of the weight of cement. The concrete cubes of M25 grade were prepared. The normal cubes and the cubes with the chemical admixture were tested. Then the behavior of the concrete is noticed to checks how the changes made in the properties with the addition of the different proportion of the chemicals. The reduction in water content is also checked with the addition of the different proportion of the chemical admixtures. The properties like consistency, initial setting time, slump cone test, water absorption test and compressive strength tests were tested. The project work also include the study of the properties of the chemicals used for the project work .It comprises of different tests for different building material such as sand, aggregates (coarse & fine aggregates), concrete and cement used for the completion of the project. The aim of the project is to find a better substitute to the costly super plasticizers available in the market and make the each project economical.
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.