Properties Of SCC Research Articles

Use of Fiber-Reinforced Self-Consolidating Concrete to Enhance Serviceability Performance of Damaged Beams

The use of fiber-reinforced self-consolidating concrete (FR-SCC) in repairing damaged concrete beams has been evaluated. An experimental program was conducted to design and test key fresh and hardened properties of SCC and FR-SCC mixtures. The designed FR-SCC mixtures included two types of supplementary cementitious materials (silica fume (SF) and slag (SL)) and two types of fibers (steel fiber (STF) and polypropylene fiber (PPF)) were used. To ensure good workability to repair congested areas, the optimized volume fractions of the STF were 0.25% and 0.50% compared with 0.10%, 0.15%, and 0.20% for the PPF. In addition, the flexural behavior of 10 beam specimens was investigated. The main reinforcement for the control beams consisted of #5 reinforcing bars, while the main reinforcement for the repaired beams was either #4 or #3 reinforcing bars that were introduced to simulate 35% and 65% reduction of the bar areas, respectively, due to corrosion. The results demonstrate that the optimized FR-SCC mixtures are effective repair materials and can develop adequate bond strength to existing concrete. The flexural test results showed that the repair mixtures were able to increase the cracking load for the repaired beams compared with the control beams. Such an increase is expected to contribute to extending the life of the damaged member or structure at the service load level. This paper also presents a comparison of the predicted values for the first-crack load strength using the ACI 544 code equation with the experimental data. Results showed that the code equation provides safe prediction.

An Experimental investigation by utilizing Plastic waste and Alccofine in Self-Compacting Concrete

Background/Objective: This study aimed to investigate in properties of Self Compacting Concrete (Fresh & Hardened properties) by utilizing Alccofine and PET fibers as a replacement of cement and fine aggregate respectively, for enhancing the workability and durability of SCC. Methods/Statistical Analysis: The Mix design was done by Nan-Su method. In this investigation an experimental program carried out for M30 grade of concrete in SCC mixes with various percentage of plastic waste from 0.5% up to 1.25% as replacement of fine aggregate and 10% Alccofine as cement replacement. Different tests in fresh properties of SCC conducted for evaluation of workability such as (slump flow, V funnel, L box and U box) and in hardened properties of SCC (compressive, flexural, tensile strength, sulfate attack, abrasion resistance, XRD, SEM & EDS) were performed for evaluating the strength and durability of SCC. Finding: From the test results it observed that utilizing of 1% plastic waste and 10% Alccofine have best performance in workability and strength of self compacting concrete and it increase the durability of SCC. Applications/Improvement: Combination of Alccofine and PET fibers can be used in SCC as a strength and durability enhancer for having a suitable concrete and sustainable construction. Keywords: Alccofine, Durability, Plastic Waste, Self-Compacting Concrete, Workability

Experimental Study on Self Compacted Concrete Mix Using Admixtures and Accessing its Performance By Comparing with Conventional Concrete (M25)

The self compacted concrete is an innovative product in civil engineering field of India. The necessity of this product was felt by civil engineers to overcome in the issue of workmanship, in structural concreting of heavily reinforced sections in execution of concrete. The introduction of SCC in the precast concrete industry was successful, with regard to application in situ; the development is slower because of the sensitivity of the product.The development of concrete that can be compacted in to every corner of a formwork by means of its own weight and without vibration is reviewed.SSC was developed to achieve durable concrete structures.This type of concrete has used by large construction companies.In recent years SSC has gained wide use for placement In reinforced concrete structures with difficult casting conditions. Sludge is a major issue since the they are the obtained from sewage and industrial waste where it causes many problems, so it can be used as admixture to the concrete because it attains more strength. In this paper, the mechanical properties of SCC in comparison to conventional concrete and concrete using sludge were discussed. The compressive strength results of hardened concrete showed that SCC gained strength slowly compared to theconventional cement concrete due to the presence of admixture and it’s 28 days strength was lower than conventional cement concrete ,but SCC eventually had potentials of higher strength beyond 90 days. Finally the effect of water cement ratio on the plastic properties of SCC was quite negligible compared to conventional method.

Effect of curing temperature and relative humidity on early age and hardened properties of SCC

The type and particle size of the additions used in SCC influence the setting and early hardening, modifying hydration speed and the development of initial properties. These processes are also altered by the curing temperature and relative humidity (RH) during Early age (EA) and would also affect SCC hardened properties.An experimental study was carried out to compare the effect of different curing temperatures, 10, 20 and 30 °C, and RH, 40 and 80%, on EA and hardened properties of SCC incorporating limestone filler (LF), microsilica (MS) and nanosilica (NS). It was observed that temperature modified the reaction speed and the evolution of EA properties while relative humidity affected evaporation and shrinkage at early age and hardened porosity and stiffness. SCC microstructure and pore-network formation were found to depend on the combination of curing conditions and the type and particle size of the additions.

Rheological and mechanical properties of self-compacting concrete with glass and polyvinyl alcohol fibres

The objective of this experimental work was to study the effect of glass and polyvinyl alcohol (PVA) fibres on fresh and hardened properties of SCC. For this purpose seven mixes; SCC, SCC with 0.1%, 0.2% and 0.3% of glass and PVA fibres by volume of SCC were prepared with a water-powder ratio of 0.35. Fresh properties were assessed using Slump flow, T500 time, L-box and V-funnel tests. Hardened properties assessed for all the four mixes were compressive strength, flexural strength, splitting tensile strength, modulus of elasticity and ultrasonic pulse velocity. Experiments revealed that after the addition of fibres workability properties (i.e. flow-ability, passing ability and resistance to segregation) were reduced slightly. Hardened properties were improved after the addition of fibres and this improvement was observed to be more in SCC mixtures with glass fibres.

Study on Effectiveness of Processed and Unprocessed Black Liquor pulps in improving the properties of PPC mortar, Concrete and SCC

The cost of construction materials is increasing day by day because of high demand, scarcity of raw materials and high price of energy. From the view point of energy saving and over consumption of resources, the use of alternative constituents in construction materials is now a global concern. From this, the extensive research and development works towards exploring new ingredients are required for producing sustainable and environment friendly construction materials. Bagasse pulp liquor is one such material that can be used as a chemical admixture which is obtained as a by-product of paper manufacturing process. Around 5 million tons of bagasse pulp is obtained throughout the world each year. since the material is a waste product from paper industry, this can be changed as a admixture by its effective use in concrete. In the present investigation black pulp liquor is added to fresh concrete in different dosages, the concrete is then tested for workability, compressive strength, flexural, split tensile strength and setting time. From results it is shown that 1% replacement of water with black pulp liquor increases the fresh properties of the concrete, 2% replacement of water with black pulp liquor increases the mechanical properties of the concrete and acts as a set retarder.

Workability of Hybrid Fiber Reinforced Self-Compacting Concrete

The aim of this work is to evaluate the effect of adding different types of fibers on the fresh properties of the self-compacting concrete, SCC. The used types of fibers were steel (with volume ratios of 0.75, 1.0 and 1.25 %) and polypropylene fibers (0.10 and 0.15 %) and a hybrid system of these fibers (0.65 % steel and 0.10 % polypropylene). The conducted tests in the fresh state were slump flow, T500, V-funnel and L-box. It was noticed that increasing the volume fraction of fibers would lead to decrease in the workability of SCC. According to EFNARC requirements for SCC, many test results were nonconforming. It was also concluded that polypropylene fibers have higher detrimental effect on fresh properties of SCC than steel fibers and that was attributed to the ability of polypropylene to absorb part of mixing water.

Review of Sustainability in Self-compacting Concrete: the Use of Waste and Mineral Additives as Supplementary Cementitious Materials and Aggregates

Concrete is one of the commonly used construction materials, but there is a need to develop a new and sustainable technology to make concrete more affordable. With the advancement in technology, concrete was no longer seen as a three entity (binder, aggregate, and water). The unique workability properties of SCC make it unique in the concrete industry. This review assessed the materials, strength, rheological properties of agricultural waste, industrial waste and mineral additives in SCC production. The effect of the utilization of these additives and replacements on structural, mechanical and rheological properties of SCC was espoused. The review revealed that the use of both industrial and agricultural waste enhances the strength properties of SCC. Additionally, the use of agricultural waste improves the rheological properties of fresh concrete. The utilization of expansive material should be discouraged in SCC production. The review revealed that SCC developments ensure a good balance between deformability and stability. It was therefore recommended that SCC should be utilized in pavement construction, particularly when high axle load is expected.

Effect on Mechanical Properties of M25 SCC with Variation of Class - F Fly Ash and GGBS

Effect on Mechanical Properties of M25 SCC with Variation of Class - F Fly Ash and GGBS

Properties and Thermal Stress Analysis of Blended Cement Self-Compacting Concrete

Self-Compacting concrete is a concrete that is able to flow and consolidate under its own weight, completely fill the formwork even in the presence of dense reinforcement, whilst maintaining homogeneity and without the need for any additional compaction. Self-Compacting concrete is achieved by using high proportions of powder content and super?plasticizers. Due to this, pronounced thermal cracking is anticipated. Thermal cracking in concrete structures is of great concern. The objective of this research is to carry out experiments and investigate fresh and hardened properties of SCC developed using a blend of ordinary Portland cement and ground granulated blast furnace slag (GGBFS), to evaluate the applicability of Japan Concrete Institute (JCI) model?equations and?to find out any similarities and differences between Self-?Compacting concrete and normal vibrated concrete—Portland blast furnace slag concrete class B. Thermal stress analysis of the proposed Self-Compacting concrete and normal vibrated concretes were investigated by simulation using 3D FEM analysis. To carry out these objectives, concrete properties such as autogenous shrinkage, adiabatic temperature rise, drying shrinkage, modulus of elasticity, splitting tensile strength and compressive strength were determined through experiments. From experimental results, it was observed that except for the fresh properties, the hardened properties of Self-Compacting exhibit similar characteristics to those of normal vibrated concrete at almost similar water to binder ratios. It was also established that Self-Compacting concrete at W/B of 32% with a 50% replacement of ground granulated blast furnace slag has better thermal cracking resistance than SCC with 30% GGBFS replacement. It is also found that provided the relevant constants are derived from experimental data, JCI model equations can be applied successfully to evaluate hardened properties of Self-Compacting concrete.

Modelling fresh properties of self-compacting concrete using Neural network technique

The purpose of this paper is to investigate the feasibility of using artificial neural network programming for the prediction of the fresh properties of self-compacting concrete. The input parameters of the neural network were the mix composition influencing the fresh properties of self-compacting concrete namely, the cement content, the dosages of limestone powder and water, fine aggregate, coarse aggregate, and superplasticizer, and other parameter of time of testing (5, 30 and 60 minutes after addition of water). The model is based on a multilayer feed forward neural network. The details of the proposed ANN with its architecture, training and validation are presented in this paper. Six outputs of the ANN models related to the fresh properties were the slump flow, T50, T60, V-funnel flow time, Orimet flow time, and blocking ratio (L-box). The effectiveness of the trained ANN is evaluated by comparing its responses with the experimental data that were used in the training process. The dosage of water was varied from 188 to 208 L/m3, the dosage of SP from 3.8 to 5.8 kg/m3, and the volume of coarse aggregates from 220 to 360 L/m3 (587 to 961 kg/m3). In total twenty mixes were used to measure the fresh properties with different mix compositions. ANN performed well and provided very good correlation coefficients (R2) above 0.957 for slump flow, T50, V-funnel flow time, Orimet flow time, and L-box blocking ratio. The predicting results for T60 was slightly lower (R2=0.823). With the calculated models these properties of new mixes within the practical range of the input variables used in the training can be predicted with an absolute error for slump flow, T50, T60, V-funnel flow time, Orimet flow time, and L-box ratio of 3.3%, 13%, 16%, 14%, 15%, and 22%, respectively. The results show that the ANN model can predict accurately the fresh properties of SCC.

Nonlinear optical properties of sodium copper chlorophyllin in aqueous solution.

BackgroundSodium copper chlorophyllin (SCC), as one of the derivatives of chlorophyll – with its inherent green features; good stability for heat, light, acids and alkalies; unique antimicrobial capability; and particular deodorization performance – is widely applied in some fields such as the food industry, medicine and health care, daily cosmetic industry etc. SCC, as one of the metal porphyrins, has attracted much attention because of its unique electronic band structure and photon conversion performance. To promote the application of SCC in materials science; energy research and photonics, such as fast optical communications; and its use in nonlinear optical materials, solar photovoltaic cells, all-optical switches, optical limiters and saturable absorbers, great efforts should be dedicated to studying its nonlinear optical (NLO) properties.MethodsIn this study, the absorption spectra and NLO properties of SCC in aqueous solution at different concentrations were measured. The Z-scan technique was used to determine NLO properties.ResultsThe results indicated that the absorption spectra of SCC exhibit 2 characteristic absorption peaks located at the wavelengths 405 and 630 nm, and the values of the peaks increase with increasing SCC concentration. The results also showed that SCC exhibits reverse saturation absorption and negative nonlinear refraction (self-defocusing).ConclusionsIt can be seen that SCC has good optical nonlinearity which will be convenient for applications in materials science, energy research and photonics.

Characterization of Self-Compacting Concrete

This paper evaluates the rheological and mechanical properties of SCC with various dosages of viscosity modifying admixture (VMA). The rheology of fresh SCC is primarily described by its yield point and plastic viscosity. The yield point defines the force required to make the concrete flow. The speed of flow of SCC is associated to its plastic viscosity which describes the resistance of SCC to flow under external stress. For this purpose, four SCC mixtures were produced with the equal water-powder ratio and other constituents, but with different dosages of VMA. The study shows that yield point and plastic viscosity of SCC increased with the dose of VMA. Mechanical properties (compressive and splitting tensile strength, modulus of elasticity) and ultrasonic pulse velocities (UPV) were improved upto a VMA dosage 0.4% and were reduced when this dose was increased to 0.6% by weight of binder. Results of mechanical properties and UPV show a good agreement when compared with the results of other researchers.

Rheological Optimization of Self Compacting Concrete with Sodium Lignosulfate Based Accelerant Using Hybrid Neural Network-Genetic Algorithm

One of the most useful innovations in concrete technology is Self Compacting Concrete that has the ability to flow efficiently and maintain material homogeneity. The rapid change in the behavior of concrete due to accelerating admixtures can significantly affect the workability properties of the mixture and reduce its ability to flow efficiently. To describe the influence of superplasticizers blended with accelerant on the rheological properties of SCC, several mixtures were tested for Slump Flow, L-Box, and Screen Stability tests. Artificial neural network was used to obtain a model describing the constitutive relationships between the material components and workability parameters of SCC and was optimized using Genetic Algorithm. Results showed that ANN was able to establish the relationship of rheology to the concrete material components and GA derived the optimum proportion for best rheological performance. Most of the design samples of SCC with blended superplasticizer and sodium lignosulfate accelerant were not able to perform well in the flowing ability due to inefficiency of the fresh SCC to flow. The increasing dosage of accelerant however rendered strong stability between the concrete particles allowing the SCC samples to resist segregation and maintain material homogeneity.

Insights on the structural and electronic properties of ScC n + , YC n + , LaC n + (n = 3–6) systems

The nature of the chemical bonds in the EC3 +, EC4 +, EC5 +, and EC6 + species (E = Sc, Y and La) has been examined in depth using a combination of different theoretical strategies. Firstly, exhaustive explorations of the relevant potential energy surfaces using a combination of stochastic and gradient-based search procedures provide us with fan-like structures in singlet and triplet spin states as the most energetically stable configurations. Secondly, the chemical bonding analysis, using natural bond orbital theory, energy decomposition analysis, quantum theory of atoms in molecules, and the adaptive natural density partitioning analysis, indicate that metal–carbon interaction in these species is best described as an intermediate point between ionic and covalent.

A Study on Durability Properties of Scc And Conventional Concrete with Recycled Coarse Aggregate

A Study on Durability Properties of Scc And Conventional Concrete with Recycled Coarse Aggregate

Effect of Steel Fibers, Polypropylene Fibers and/ or Nanosilica on Mechanical Properties of Self-Consolidating Concrete

This research concerned studying the combined effect of using nano-silica and/ or hybrid fibers on key mechanical properties of self-consolidating concrete SCC. A comprehensive experimental work has been carried out, using steel fiber (SF) with volume fraction (0, 0.5% and 1.5%), polypropylene fiber (PPF) (0%, 0.05% and 0.15%) and SiO2 nanoparticles (0%, 2% and 4%) by weight of powdered material (silica fume- Sf ) with constant w/c ratio (0.48) to produce eleven different mixtures and tested at different ages (7, 28 and 90 days). Results showed that adding fibers adversely affect SCC workability and thus more dosage of super plasticizer (SP) should be added to stay within the standard limits. comparable to conventional concretes, the presence of steel fibers with SCC provide slight increase in compressive strength at 28 days, (up to 11%), while significant enhancement in tensile properties were observed (up to 24% and 32% for splitting and flexural strength respectively). Polypropylene or hybrid fibers however, provide lower enhancement compared with steel fibers. In contrast, implementation of nanosilica leads to significant improvement in concrete strengths particularly at 4% dosage. Combined effect of 4% nanosilica and 1.5% of steel fibers provide the superior hardening effect on the flexural performance compared with softening effect provided by other added dosages. Scanning Electron Micrograph (SEM) images confirm the matrix densification effect due to nanosilica adding. Flexural strength of SCCs without nanosilica was generally higher than splitting testing results. This fact does not change even with the presence of nanosilica and/ or fibers.

STUDY ON THE MECHANICAL PROPERTIES AND FRACTURE BEHAVIOR OF CHOPPED STEEL FIBER REINFORCED SELF COMPACTING CONCRETE

The growth of Self Compacting Concrete is revolutionary landmark in the history of construction industry resulting in predominant usage of SCC worldwide nowadays. It has many advantages over normal concrete in terms of enhancement in productivity, reduction in labor and overall cost, excellent finished product with excellent mechanical response and durability. Incorporation of fibers further enhances its properties specially related to post crack behavior of SCC. Hence the aim of the present work is to make a comparative study of mechanical pr operties of selfconsolidating concrete, reinforced with different types of fibers. The variables involve in the study are type and different percentage of fibers. The basic properties of fresh SCC and mechanical properties, toughness, fracture energy and sorptivity were studied. Microstructure study of various mixes is done through scanning electron microscope to study the hydrated structure and bond development between fiber and mix. The fibers used in the study are 12 mm long chopped glass fiber, carbon fiber and basalt fiber. The volume fraction of fiber taken are 0.0%,0.1%,0.15%,0.2%,0.25% ,0.3%. The project comprised of two stages. First stage consisted of development of SCC mix design of M30 grade and in the second stage, different fibers like Glass, basalt and carbon Fibers are added to the SCC mixes and their fresh and hardened properties were determined and compared. The study showed remarkable improvements in all properties of self-compacting concrete by adding fibers of different types and volume fractions. Carbon FRSCC exhibited best performance followed by basalt FRSCC and glass FRSCC in hardened state whereas poorest in fresh state owing to its high water absorption. Glass FRSCC exhibited best performance in fresh state. The present study concludes that in terms of overall performances, optimum dosage and cost Basalt Fiber is the best option in improving overall quality of self-compacting concrete.

PROPERTIES OF SELF COMPACTING CONCRETE WITH METAKAOLIN REPLACING SAND WITH GBFS

After Agriculture Industry in India. Construction sector contribute 11% to the GDP. Hence construction Industry plays a crucial role in economic development for any construction. Sand is the major material for preparation of mortar and self compacting concrete. But the problem here is sand is largest basic consumer non-renewable resource. Hence it is our responsibility to safeguard the sand for future generation. Today this is an almost scarcity of national sand and due to continuous excavation of river beds there is some serious effect on ecology ever. It’s the time to think for alternate material to replace the river sand and for any mix design of self compacting concrete higher %age of powder content & sand is required. In the present paper we have put an effort to replace the sand with GBFS by–product of steel and iron manufacturing plant. Test result of GBFS meets the national standard of fine aggregates (IS 38 3 1970) GBFS does not contain material that may affect the strength and durability of concrete such as chlorides, organics impurities. It is free from emission of Co2. In the present paper M40 grade of SCC was considered with different replacement of sand with G.B.F.S. Further it is studied that the effect of MetaKaolin on the properties of GBFS self compacting concrete, the studies include the effect of GBFS and MetaKaolin on the fresh and hardened mechanical properties of SCC made with GBFS and MetaKaolin. The observation made that river sand can be replaced up to 60% with constant W/C ratio 0.38% the only problem with GBFS, it takes long time to gain strength. If we add the admixtures METAKAOLIN by 10%, then quick setting & early strength is possible. The GBFS is free from Co2, Alkalis and silt, Co2.The fresh properties & compressive strength of SCC increases with the increase in the percentage of GBFS. But limited to 60% replacement provided by adding 10% MetaKaolin. It is found that 70% replacement not reached satisfactory results. It is economical when compared with natural sand and also reliable alternative material in terms of workability, strength and durability. As there is broader slope for advancement in construction Industry. Therefore there is an immense necessity to know for alternative to natural river sand, this paper further detail about the fresh and hardened properties chemical properties briefly in full length submission. The fresh properties and compressive strength of self compacting concrete is improved as percentage of GBFS increases with constant MetaKaolin (%). The study has revealed that using MetaKaolin in the replacement f river sand with GBFS gives better flow properties and compressive strength in comparison to only GBFS

Modelling the fresh properties of self-compacting concrete using support vector machine approach

The main objective of the study presented in this paper was to investigate the feasibility using support vector machines (SVM) for the prediction of the fresh properties of self-compacting concrete. The radial basis function (RBF) and polynomial kernels were used to predict these properties as a function of the content of mix components. The fresh properties were assessed with the slump flow, T50, T60, V-funnel time, Orimet time, and blocking ratio (L-box). The retention of these tests was also measured at 30 and 60min after adding the first water. The water dosage varied from 188 to 208L/m3, the dosage of superplasticiser (SP) from 3.8 to 5.8kg/m3, and the volume of coarse aggregates from 220 to 360L/m3. In total, twenty mixes were used to measure the fresh state properties with different mixture compositions. RBF kernel was more accurate compared to polynomial kernel based support vector machines with a root mean square error (RMSE) of 26.9 (correlation coefficient of R2=0.974) for slump flow prediction, a RMSE of 0.55 (R2=0.910) for T50 (s) prediction, a RMSE of 1.71 (R2=0.812) for T60 (s) prediction, a RMSE of 0.1517 (R2=0.990) for V-funnel time prediction, a RMSE of 3.99 (R2=0.976) for Orimet time prediction, and a RMSE of 0.042 (R2=0.988) for L-box ratio prediction, respectively. A sensitivity analysis was performed to evaluate the effects of the dosage of cement and limestone powder, the water content, the volumes of coarse aggregate and sand, the dosage of SP and the testing time on the predicted test responses. The analysis indicates that the proposed SVM RBF model can gain a high precision, which provides an alternative method for predicting the fresh properties of SCC.