Self-consolidating Concrete Research Articles

Characterizations of self-consolidating concrete (SCC) from a physicalmechanical perspective with various additions

Self-consolidating concretes (SCC) are special concretes that have the particularity of being very fluid and have been developed over the past thirty years. They are still qualified today as "new concretes" because their use remains modest, although they have strong development potential. The specificity of SCC compared to ordinary vibrated concrete (OC) lies in the fact that it is extremely fluid and does not require vibration to be implemented. Compacting under the effect of their own weight, they can be poured in areas with a high density of reinforcement. For the formulation of self-consolidating concretes, a large volume of mineral addition is necessary so as to reduce the quantity of cement induced by the increase in the volume of paste necessary to allow the flow of the concrete. The main objective of this work was to determine the effect of different cement additions (Filler limestone (Fc), crushed dune sand (Sd), and silica fume (Fs)) by partial substitution of a certain quantity of Portland cement on the physical-mechanical properties of SCC using the capillary absorption test. The results obtained demonstrate that all self-consolidating concretes give interesting results in terms of compressive strength and water absorption.

The effect of nano-silica powder on mechanical and non-mechanical characteristics of self-consolidating concrete (SCC) and its impact on environment protection

The effect of nano-silica powder on mechanical and non-mechanical characteristics of self-consolidating concrete (SCC) and its impact on environment protection

Influence of waste foundry sand on microstructural and mechanical behavior of self consolidated concrete filled steel columns

The impacts of leftover foundry sand on steel sections filled with high strength Self-Consolidated Concrete (SCC) were investigated and addressed in this study. 24 steel sections were examined under progressive axial pressure to establish the optimal proportion of leftover foundry sand, a byproduct. 24 samples were divided into 12 columns with eight circular cross sections of 50 mm in radius and 500 mm in length, and eight additional specimens with square sections of 500 mm in length and 100 mm on each side. Additional 12 columns with eight circular specimens measuring 50 mm in radius and 1000 mm in height and eight square specimens measuring 100 mm on each side and 1000 mm in length. The twelve sections can be divided into hollow steel sections and SCC filled sections. The predicted outcome from the studies show that the capability of carrying axial loads and ductility of the SCC-filled steel sections are affected by the use of leftover foundry sand. Additionally, the steel section parts serve as external reinforcement to promote lateral stability and decrease local buckling. The square sections use 25% less steel than the circular sections. By substituting leftover foundry sand for some of the cement, SCC mixes are made. In this project, steel sections filled with self-consolidated concrete were made using varying amounts of leftover foundry sand, including 0%, 4%, 8%, 12%, 16% and 20%. According to the analysis, steel columns with leftover foundry sand have a higher ultimate load than standard concrete, which results in a 12% reduction in construction costs. The work offers a remedy for efficient byproduct management that lessens environmental risk and creates an atmosphere that is eco-friendly.

Fresh Properties of Self-Consolidating Expired Cement-Fly Ash Cold Bonded Lightweight Aggregate Concrete With Different Mineral Admixtures

The experimental program evaluated the fresh properties of self-consolidating lightweight concretes (SCLC) produced from expired cement EC cold-bonded lightweight coarse aggregates (ALA) with silica fume (SF) and fly ash (FA). Twelve mixtures of SCLC were prepared, the binder in the control mix was just Portland cement (PC), whereas other mixes included binary and ternary of (PC), 20% of (FA), and/or (10%) of (SF) with (0%, 50%, and 100%) as partial replacement of (ALA) with coarse natural aggregates. Fresh features of (SCLC) were evaluated by measuring their slump flow diameter, T500 slump flow time, V-funnel flow time L-box height ratio, and column segregation, (SCLC) with and without mineral admixtures have their fresh characteristics compared. It was found that increasing the quantity of ALA replacement resulted in a reduction in the amount of superplasticizer required to obtain a constant slump flow diameter of SCLC. Combining (SF) and/or (FA) lowered both the V-funnel flow time and the slump flow time, whereas the L-box height ratio increased from (0.82) to (0.86) with the addition of fly ash for reference mix. With the combined action of mineral admixtures, the percentage of column segregation decreases by (16.7%) compared with the reference mix. The maximum slump flow was (792) mm with a mix of (M6).

Flow Test of Self Compacting Concrete using V-Funnel Test

Abstract: This paper gives a review on Self Compacting Concrete (SCC) to be made using various Mineral Admixtures and Fibres. In current scenario of construction industries due to demand in the construction of large and complex structures, which often leads to difficult concreting conditions. When large quantity of heavy reinforcement is to be placed in a reinforced concrete (RC) member, it is difficult to ensure fully compacted without voids or honeycombs. Compaction by manual or by mechanical vibratos is very difficult in this situation. That leads to the invention of new type of concrete named as selfcompacting concrete (SCC). This type of concrete flows easily around the reinforcement and into all corners of the formwork. Self- compacting concrete describes a concrete with the ability to compact itself only by means of its own weight without the requirement of vibration. Self –compacting concrete also known as Self-consolidating Concrete or Self Compacting High Performance Concrete. It is very fluid and can pass around abstractions and fill all the nooks and corners without the risk of either mortar or other ingredients of concrete separating out, at the same time there are no entrapped air or rock pockets. This type of concrete mixture does not require any compaction and is saves time, labour and energy. This review paper explains the utilization of fibres and various mineral admixtures in the properties of Self Compacting Concrete. The Benefits and Uses of SSC are discussed in this paper and Self-Compacting Concrete is compared with Cement Concrete. A V-Funnel is used to measure the flowability of concrete, and cost of Manufacturing a V-Funnel using Mild steel and Stainless Steel is estimated.

Performance of Stalite lightweight SCC beam-column joints under reversed cyclic loading

This paper investigates the structural performance of Stalite lightweight self-consolidating concrete (LWSCC) beam-column joints under quasi-static reversed cyclic loading. Six beam-column joints made with different lightweight aggregate types (Stalite lightweight coarse [LC] and fine [LF] aggregates) and designed with/without joint shear reinforcement were cast and tested. The performance of tested specimens was assessed in terms of failure mode, hysteretic response, deformation, strength degradation, ductility, brittleness index, and energy dissipation capacity. The applicability and accuracy of design code provision in predicting the shear and flexural strengths of the tested joints were also investigated. The results indicated that it is possible to design Stalite LWSCC mixtures with a density ranging from 1888–1966 kg/m3, having a sufficient structural performance under cyclic loading. Properly designed LWSCC beam-column joints made with Stalite aggregates slightly reduced the load-carrying capacity by around 8.5% and ductility and dissipated energy by around 11.4% and 15.8%, respectively, compared to the normal-weight SCC (NWSCC) specimen. Despite the brittle nature of Stalite lightweight aggregates, LWSCC joints with sufficient hoops exhibited satisfactory cyclic performance and experienced ductile flexural beam failure. The results also indicated that LWSCC specimens containing Stalite fine aggregates showed better structural performance in terms of load-carrying capacity, strength degradation, ductility, brittleness index, and energy dissipation capacity compared to counterpart specimens made with Stalite coarse aggregates.

Numerical validation and optimization of hybrid composite beam hull using multiple failure criteria

The number of structurally deficient bridges continues to increase due to corrosion of steel sections and concrete rebar, therefore the replacement of decaying structures and the development of innovative systems have become of high priority to extend the life span of newly built bridges. Hybrid Composite Beam (HCB) produced by Hillman is one of those systems that use a combination of materials i.e., concrete, steel, and Glass Fiber-Reinforced Polymer (GFRP) to integrate each main advantage in a single bridge beam structure. Despite its several apparent advantages; it is not widely spread as expected within the last decade. The HCB is manufactured of self-consolidating concrete (SCC), which is poured in the shape of a traditional arch and tied at its ends by high-strength tendons. A durable FRP composite hull encapsulates the SCC arch and the high-strength tying tendons in order to create a structural beam element for bridge applications. The HCB's design aims to provide pure compressive stresses to the concrete and pure tensile stresses to the steel. The current study performs a deep numerical investigation of the FRP hull instead of other components comprehensively studied. Numerical validation is performed for the deflection results on the experimentally tested Knickerbocker HCB Bridge, the deformations are validated at four stages of HCB manufacturing and testing. Further, the FRP hull strength ratios are quantified for the worst value of four failure criteria. The results showed an excess use of FRP material, where more than 90% of FRP areas have strength ratios of 5 to 50. The FRP hull thickness is minimized using Genetic Algorithm optimization under the worst case of loading. The results achieved more than 60% decrease in FRP weight, that led to only 20% cost difference between traditional precast concrete and HCB girders. It is finally concluded that the overdesign of FRP hull contributed to the high cost of HCB usage consequently inefficient market spread.

New insight on rheology of self-consolidating earth concrete (SCEC)

Self-consolidating earth concrete (SCEC) is a novel alternative to facilitate the earth-based construction. A new concrete-equivalent mortar (CEM) approach with constant excess-paste (EP) thickness was proposed to evaluate the rheological and thixotropic properties of various SCEC mixtures proportioned with different clay and superplasticizer types. The use of non-esterified polycarboxylate (NE-PC) and sodium polynaphtalene superplasticizer types in combination with a finer clay type led to a thixotropic behavior. Mixtures made with sodium hexametaphosphate resulted in significantly high yield stress and plastic viscosity values. The rheological properties were mainly controlled by the admixture type, followed by the type and content of clay and water-to-powder ratio (W/P). Empirical models were proposed to predict the rheology of earth-based paste, CEM, and SCEC mixtures using the governing key mixture parameters, including the fineness of the powder constituents (i.e., clay, silt, and cement), water content, EP thickness, paste volume, and packing of the granular skeleton.

Early Age Shrinkage of Self-Consolidating Concrete Incorporated with Three Shrinkage-Reducing Components

Early Age Shrinkage of Self-Consolidating Concrete Incorporated with Three Shrinkage-Reducing Components

Semi-flowable self-consolidating concrete using industrial wastes for construction of rigid pavements in India: An overview

Semi-flowable self-consolidating concrete using industrial wastes for construction of rigid pavements in India: An overview

Hygrothermal and microstructural characterization of self-consolidating earth concrete (SCEC)

The incorporation of earth-based materials offers the construction industry superior hygrothermal performance, hence ensuring significant ecological and environmental benefits. The hygrothermal and microstructural characteristics of self-consolidating earth concrete (SCEC) are investigated in this study. These traits include the sorption isotherm, permeability, heat capacity, thermal parameters (conductivity, diffusivity, and effusivity), moisture buffer value (MBV), total porosity, pores distribution, and microstructural characteristics. The sorption isotherm tests revealed that the investigated SCEC mixtures gained lower water content (around half) compared with the reference self-consolidating concrete (SCC) mixture (1.5% vs. 3.3% at 90% relative humidity). These results are comparable to those reported for clay bricks in the literature. The SCEC mixtures also showed higher permeability due to their higher porosity and connected pores. Thermal conductivity, diffusivity, and effusivity of the investigated SCEC mixtures showed lower values than those of the reference mixture. At 10 °C, the investigated SCEC mixtures exhibited lower thermal conductivity values of 0.400–0.500 W m−1 K−1 compared with those of the reference mixture (0.765 W m−1 K−1). Since the diffusivity and effusivity of the earthen materials are higher than those of wood, SCEC mixtures can offer both low diffusivity and high effusivity among different construction materials. Furthermore, the investigated SCEC mixtures exhibited lower mass losses attributed to calcium silicate hydrate (CSH), dehydroxylation of portlandite, and decarbonation than the reference mixture. The water vapor and gas permeability of SCEC were in good agreement with cumulative pore volume in the ranges of 100–200 nm and 100–300 nm, respectively. On the other hand, the drying shrinkage and compressive strength values were dependent on the cumulative pore volume of pore sizes less than 1 μm.

Performance Modeling of Spherical Capsules during Mixing of Self-Consolidating Concrete

Autonomous healing is a very promising technique in self-healing concrete systems. For capsules to achieve their anticipated performance, they should be able to survive the harsh mixing conditions of concrete, yet rupture upon concrete cracking. At present, there are no standard test methods, either experimental or analytical, for determining the capsule survival rate during concrete mixing. This study investigates the correlation between the capsules' shell properties, concrete rheological properties, the capsules' external forces, and capsule survival rate during concrete mixing. Finite element and statistical modeling techniques were employed to evaluate the capsule performance and predict the survival rate of capsules during concrete mixing, with 68% confidence. The results revealed that the capsules' survivability during concrete mixing is highly influenced by the capsule's radius-to-thickness ratio, the rheological properties of the fresh concrete, the average-paste-thickness (APT) of the concrete mix, the aggregate content and angularity, and the speed of the mixer. In brief, capsules with a radius-to-thickness ratio between 30 and 45 are likely to survive concrete mixing and yet still rupture upon concrete cracking.

Sustainable Design of Self-Consolidating Green Concrete with Partial Replacements for Cement through Neural-Network and Fuzzy Technique

In order to achieve a sustainable mix design, this paper evaluates self-consolidating green concrete (SCGC) properties by experimental tests and then examines the design parameters with an artificial intelligence technique. In this regard, cement was partially replaced in different contents with granulated blast furnace slag (GBFS) powder, volcanic powder, fly ash, and micro-silica. Moreover, fresh and hardened properties tests were performed on the specimens. Finally, an adaptive neuro-fuzzy inference system (ANFIS) was developed to identify the influencing parameters on the compressive strength of the specimens. For this purpose, seven ANFIS models evaluated the input parameters separately, and in terms of optimization, twenty-one models were assigned to different combinations of inputs. Experimental results were reported and discussed completely, where furnace slag represented the most effect on the hardened properties in binary mixes, and volcanic powder played an effective role in slump retention among other cement replacements. However, the combination of micro-silica and volcanic powder as a ternary mix design successfully achieved the most improvement compared to other mix designs. Furthermore, ANFIS results showed that binder content has the highest governing parameters in terms of the strength of SCGC. Finally, when compared with other additive powders, the combination of micro-silica with volcanic powder provided the most strength, which has also been verified and reported by the test results.

Mass Concrete Mixtures Optimized for Temperature Control and High Workability

Mass concrete is prone to thermal cracking, deleterious chemical reactions, and ultimate strength reduction caused by a high temperature rise. Defining mass concrete has been difficult since many factors affect the thermal behavior and the distress formation. Mass concrete is usually reinforced and may have geometric constraints that require concretes with high workability, as with self-consolidating concrete. For high workability and strength, high amounts of cementitious material are used for stability and low water–cementitious material ratios. Such amounts generally cause high water and paste contents that lead to cracking because of moisture loss and thermal contraction. In this study, a practical and useful definition of mass concrete was explored. Concretes with low cementitious material contents and high workability were investigated. To minimize the total cementitious material and paste contents, optimum aggregate gradations were considered. To achieve and maintain high workability during construction, a combination of admixtures was used that included high-range water reducing, workability-retaining, and viscosity-modifying admixtures. Laboratory testing of concretes with reduced cementitious material contents including high amounts of the supplementary cementitious materials and a combination of admixtures showed that concretes with a decreased temperature rise, high workability, and adequate strength can be obtained.

Structural Behavior of Bridge Deck Slabs Made with GFRP-Reinforced Lightweight Self-Consolidating Concrete

The use of lightweight self-consolidating concrete (LWSCC) has significantly increased due to enhanced mix designs and its projected lower overall costs than normal-weight concrete. Accelerated bridge construction (ABC) has become a common alternative to conventional construction techniques. The use of LWSCC in ABC will reduce structural loads and expedite transportation and installation of precast bridge elements. Limited research, however, has investigated LWSCC bridge elements reinforced with glass fiber–reinforced polymer (GFRP) bars. This paper reports on the performance of full-scale edge-restrained bridge deck slabs (simulating slab-on-girder bridges) fabricated with LWSCC reinforced with GFRP bars. The test specimens included three edge-restrained slabs and one unrestrained slab for comparison. The test specimens were 3,000 mm long × 2,500 mm wide × 200 mm thick and were tested up to failure under a concentrated load simulating the footprint of a standard CL-625 truck wheel load (87.5 kN) defined in current design codes. The investigated parameters were (1) reinforcement ratio; (2) top reinforcement; and (3) effect of edge-restraining. The cracking behavior, ultimate capacity, deflection, and concrete and reinforcement strains of the specimens were presented and discussed. In addition, the punching-shear capacity of the tested specimens was assessed with the currently recommended design equations. The test results indicate that the overall performance of LWSCC deck slabs reinforced with GFRP bars is similar to such structures made with normal-weight concrete.

The efficiency of statistical and artificial neural network techniques on evaluating and predicting compressive strength of sustainable SCC with basalt fibers

This work presents the power of employing statistical and Artificial Intelligence (AI) approaches in analyzing and predicting the effect of basalt fibers on the mechanical behavior of high-strength sustainable self-consolidating concrete (SCC). To alleviate the greenhouse gas emission from the Portland cement manufacturing process, an experimental program with a concrete mix design of up to 80% of the cement content is replaced with a combination of different supplementary materials. The used cementitious materials (i.e., ground granulated blast furnace slag (GGBS), fly ash (FA), and silica fume (SF)) were employed in the design mix as binary, ternary, and quaternary blends with different proportions of cement replacement. Additionally, basalt fibers were integrated into the concrete mixtures with three dosages from the total cementitious materials weight, i.e., 0.5%, 0.75%, and 1.00%. The aim of introducing those fibers was to investigate their ability in enhancing or regaining the mechanical strength compromised with cement replacement. As the compressive strength results showed some ambiguous trends with basalt fiber mixes, analysis of variance (ANOVA) was used to determine the controlling parameter on the compressive strength behavior. The analysis elucidated that the highest contributor to the strength was cement with 58%, followed by the GGBS with 21%, while the remaining factors were 12%, 6%, and 3% for FA, SF, and basalt fibers, respectively. Further, all the experimental data were utilized in an Artificial Neural Networks (ANN) tool to predict the compressive strength of the developed SCC mixes. For maximum prediction accuracy, different network configurations for one-hidden and two-hidden layers networks were exploited. Results demonstrated that high prediction accuracy was attained through 6-28-1 and 6-25-20-1 networks with a high confidence level limited to a ±10% error margin. It was concluded that statistical, and ANN techniques to analyze, capture, and predict the effect of different additives on the concrete compressive strength are efficient despite having ambiguous behavior with the experimental results.

Comparing and evaluating influence of nylon fiber and fly ash in self compacting concrete

Self-consolidating concrete (SCC) is a special concrete that is highly flow able, non-segregating and self-expanding. Self-compacted concrete (SCC) is poured into the formwork without compaction and fills the formwork by its own weight. SCC is considered to have many advantages. Compared with conventional concrete as improved Construction quality, faster construction activity, lower cost etc. This project was carried out to evaluate the effects of addition of nylon fiber and fly ash on the fresh and hardened properties of SCC mixes. In this project, concrete mixes with nylon fiber of 0.5%, 1.5%, 2.5%, and fly ash with 0%, 15%, 30% and 45% were used to determine its permeability, flow Capacity, evaluated on the basis of and separation resistance, slump flow, L-box and V-funnel tests. After 3 days, 14 days, 28 days of curing SCC cylinders, compressive and splitting tensile strength were tested. The test results show that nylon fibers increase permeability but decrease the filling capacity and segregation resistance of SCC. Furthermore, it can be concluded that after 3 days, 14 days, 28 days of curing, the test of concrete samples showed that the addition of nylon fiber up to 2.0% of cement by volume increased the compressive strength of SCC. Strength, improves tensile strength but 2.5%. Nylon fiber reduces the compressive strength, tensile strength of hardened SCC.

Procedure for mix designing used for steel fibre reinforced self-compacting concrete

This work focuses on a methodical design process for developing self-compacting concrete (SFRSCC) using steel fibre reinforcements. The objective is to create a self-consolidating concrete that has the double advantage of self-consolidating characteristics and composite toughness. Experimental modelling involved building the mortar phase with manufactured sand (M-sand) as fine aggregate utilising a systematic mix design process based on the particle packing idea. Optimisation of aggregates was determined using the packing density idea and slump cone research. By conducting a paste consistency test, cement and ground granulated blast furnace slag (GGBFS) powder combinations were chosen. Finally, the amount of superplasticizer was determined based on Marsh cone experiments and the percentage by volume of steel fibres determined by slump flow research. The addition of steel fibre dosage impacts the workability of both standard and high strength concrete, and the fresh properties emphasised the necessity to maintain a large paste volume for increased workability. On the basis of the recommended mix design technique using M-sand, self-compacting concrete with a maximum strength of 70MPa was manufactured. On the other hand, experimental studies on the fresh and hardened properties of recommended self-compacting steel fibre concrete mixes were presented. In addition, test findings demonstrated the viability of employing M-sand as a replacement for river sand in its entirety.

External Sulfate Attack of Ambient-Cured One-Part Alkali-Activated Self-Consolidating Concrete

The mechanism of sulfate attack on alkali-activated materials, particularly the alkali-activated self-consolidating concrete (AASCC), is complex and contradictory. This could be due to the wide range of precursor and activator materials used in the production of AASCC mixtures, which has called into question the reliability and validity of existing evaluation procedures and practices. This paper presents a systematic research effort on AASCC mixtures, based on granulated blast-furnace slag, prone to various sulfate attack scenarios that are thought necessary to establish a proposed criterion. The conducted experimental design demonstrated that single-, binary-, and ternary-precursor AASCC samples, activated with 1:1 Na2CO3 and MetaNa2SiO3, partially submerged in sodium, magnesium, and mixed sulfate solutions could experience a dual sulfate attack scheme. Sulfate attack can occur in the immersed section in sulfate solutions, while physical sulfate attack can occur in the portion above the solution level. The influence of physical sulfate attack on the concrete’s characteristics was not significant given that the damage was confined to the outer surface. However, the damage was primarily monitored by the AASCC different systems’ pore structure, which resulted in the leaching of ions from samples to solutions. It was found that maintaining the pH in the sulfate solutions increased the rate of damage of AASCC mixtures. Furthermore, binary, and ternary precursor blends partially replacing slag with SF, or FA resulted in decreased porosity, surface scaling, and AASCC deterioration caused by an expansion in the volume of very small diameter pores. Finally, in all AASCC systems, gypsum and ettringite were the primary degradation products of sulfate attack.

Effect of concrete mixture on shear behavior of prestressed concrete girders

A total of six shear-critical prestressed concrete (PC) I-girder were tested to investigate the effect of concrete mixture types on the shear behavior of PC girders. The concrete mixtures examined were conventional concrete (CC), high-performance concrete (HPC), and self-consolidating concrete (SCC) with normal (specified fc′=41.4 MPa) and high (specified fc′=68.9 MPa) compressive strengths. Test results showed that the HPC girders exhibited a shear behavior similar to the CC girders, irrespective of the concrete compressive strength. The SCC girder with normal-strength concrete (SCC-N) showed a higher ultimate shear strength ratio (Vult/Vn) and higher ultimate displacement than the corresponding CC girder (CC-N). The SCC-N mixture was designed with a similar coarse aggregate amount but a reduced maximum coarse aggregate size compared with the CC-N mixture. The better performance of SCC-N may be attributed to a better filling ability of the SCC-N mixture than the CC-N mixture. The SCC girder with high-strength concrete showed a lower Vult/Vn than the corresponding CC girder (CC-H). The lower shear strength of the SCC girder may be attributed to the lower coarse aggregate amount (19% lower) than the CC-H girder. A shear test database of PC girders was established to investigate further the effect of coarse aggregate amount on the girder shear strength. Based on the statistical analysis, the Vult/Vn and coarse aggregate amount either showed a positive or insignificant correlation. For those groups of test data that showed positive correlation, the slopes of the linear regression of the test data showed that for a 100 kg/m3 decrease of coarse aggregate amount, the Vult/Vn decreased in average by 18.5%.