Self-Consolidating Concrete

Corrosion initiation time of embedded steel is an important service life parameter, which depends on concrete material make-up, exposure environment, and duration of exposure. Early and accurate determination of corrosion initiation time will aid in designing durable reinforced concrete, saves cost and time. This study leveraged on the power of ensemble machine learning by combining the performances of different models in estimating the corrosion initiation time of steel embedded in self compacted concrete using corrosion potential measurement. The concrete specimens were prepared with limestone powder as supplementary addition to Portland cement and was exposed to 5% sodium chloride in accordance with the requirements of ASTM C876-15 for 8 months. During the exposure, corrosion potential of the embedded steel was measured, and the recorded datasets were used in training five different machine learning models. With cement, limestone powder, coarse aggregate, fine aggregate, water and exposure period.as input variables, five different models were developed to estimate the corrosion initiation time (determined from the corrosion potential measurements) of the embedded steel. With respect to model predictive performance, the acquired results demonstrated that the random forest (RF) ensemble model amongst other trained models performed best with 85/15 dataset percentage split for the training and testing. RF ensemble performed best with CC and RMSE of 99.01% and 18.2747 mV for training, and 98.67% and 25.0298 mV for testing respectively. Hence, due to its superior and robust performance, this study proposes RF ensemble model in the estimation of corrosion initiation time of embedded steel in reinforced limestone-cement blend concrete.

The objective of this research was to develop guidelines for use of SCC in precast, prestressed bridge elements, including recommended changes to the AASHTO Load and Resistance Factor Design (LRFD) Bridge Design Specifications [2004, 2007] and LRFD Bridge Construction Specifications [1998], hereafter referred to as the AASHTO LRFD Specifications.
Such guidelines will provide highway agencies with the information necessary for considering SCC mixtures that are expected to produce a uniform product, expedite construction, and yield economic and other benefits. To accomplish this objective, the research included work to:
• Develop material properties and performance criteria for SCC used for precast, prestressed concrete bridge elements;
• Evaluate key engineering properties, durability characteristics, and structural performance of such concrete; and
• Propose relevant changes to AASHTO LRFD Specifications.

Specifically, this project:
• Developed SCC mixtures that can be produced consistently in the field;
• Identified test methods for use in SCC mix design;
• Identified test methods for use for quality control in precasting plants;
• Developed specifications and criteria for SCC mixtures for precast, prestressed concrete bridge elements;
• Determined the influence of mix parameters, such as raw materials, mixture proportioning, mixing, production, placement, and characteristics of the cast element;
• Compared performance of precast, prestressed concrete elements made with SCC with those made with conventional high-performance concrete;
• Prepared guidelines for testing, proportioning, and casting SCC bridge elements; and
• Investigated applicability of current models recommended by AASHTO LRFD Specifications
and suggested revisions whenever applicable.

The following thesis presents the results of four full scale beams tests as part of a research program conducted at McGill University. The purpose is to study the applicability of existing design provisions, in the American Association of State Highway and Transportation Officials (AASHTO) specifications, for the use of self-consolidating concrete (SCC) in precast pretensioned bridge girders.
The test specimens had an overall length of 31 ft (9.4m) with a center-to-center span of 29 ft (8.8m). They were cast in four batches with different concrete attributes: two non air-entrained SCC mixtures and two high-performance concretes. For each type, compressive strengths of 8,000 and 10,000 psi (55.2 and 69 MPa) with release strengths of 5,000 and 6,250 psi (34.5 and 43 MPa) at 18 hours, respectively, were tested. Each girder was prestressed with eight Grade 270 seven-wire low-relaxation prestressing strands of 0.6 in (15.2 mm) diameter. Six of the strands were straight and two were harped twice, 4’-11” (1.5 m) from mid-span. The specimens were supported on neoprene bearing pads at their ends, and were tested with two equal point loads located 4’-11” (1.5 m) from mid-span.
This research project demonstrated that the shear failure of the girders exceeded the predicted nominal shear resistance given by the 2004 AASHTO Specifications. The experimental flexural resistance also exceeded the predicted nominal resistance.

This study evaluates the effect of waste polyethylene terephthalate (PET) granules on the fresh, mechanical and absorption characteristics of self-consolidating concretes (SCCs). Fine aggregates were replaced with different percentages (from 0% to 8%) of PET granules obtained by crushing waste PET bottles. The fresh properties of SCC containing PET granules were determined using slump flow and V-funnel flow time tests. Mechanical properties (compressive strength and splitting tensile strength tests) and absorption properties (sorptivity and water absorption tests) were evaluated. The results indicated that utilization of waste PET granules in production of SCC could be an effective way for recycling purpose. The maximum amount of PET replacement should be limited to 5%. Exceeding 5% of PET content may result in an increase of V-funnel flow time to overpass the limiting value, decrease in compressive strength, reduction in sorptivity and increase in the water absorption. The production of high performance SCC containing 5% PET granules satisfies all the requirements for SCC with satisfactory outputs.

The concurrent effects of recycled concrete aggregate (RCA) and polypropylene fibers (PPF) on workability of self-consolidating concrete (SCC) are not quantified in literature. Different SCC series containing 25% to 100% RCA and 0.25% to 1.75% PPF are investigated in this study; the water-to-binder ratio varied from 0.38 to 0.5, while high-range water reducer adjusted to maintain slump flow at 700 ± 25 mm. Flowability, cohesiveness, passing ability, and segregation resistance were evaluated and compared with the limitations specified by the European Guidelines for SCC. Test results have shown that SCC rheological properties and passing ability dramatically curtailed with PPF inclusions, especially when mixtures are proportioned with higher RCA replacement rates. This was attributed to combined effects of fiber additions that hinder the cement matrix deformation together with increased RCA surface roughness that accentuates internal friction and resistance to flow. Mixtures containing increased RCA and PPF concentrations exhibited better stability, reflected by reduced aggregate segregation. Series of regression models were proposed to predict the coupled effects of RCA and PPF additions on SCC workability responses.

Properly designed self-consolidating concrete (SCC) should have high deformability while maintaining high stability to secure homogeneous properties of hardened concrete. This paper aims at correlating the stability characteristics to material performance of self-consolidating concrete-equivalent-mortars (SCCEMs) made with various binary and ternary cement blends of fly ash (FA) and metakaolin (MK). The stability characteristics of the mixtures were determined using mini-column segregation, mini V-funnel flow time, visual stability index (VSI), and hardened visual stability index (HVSI) to assess both static and dynamic stability. A response surface method (RSM) was conducted to mathematically evaluate the level of significance of mixture parameters and their coupled interactions on the performance of SCCEMs. Trade-off contour diagrams between investigated mixture constituents and the modeled responses were illustrated.

Test results indicate that binder composition have substantial influence on dynamic and static stability. Based on the established correlation between stability and overall performance, SCCEMs with a higher segregation index (SI) values are expected to have lower fresh and hardened properties. A ternary combination of 25% FA and 25% MK with a SI value of 5 achieved the highest overall material performance among the tested binary and ternary cementitious systems. The slump flow and V-funnel flow time tests are shown to be an efficient tool for controlling static segregation of mixtures. Mixtures with higher level of fluidity and lower flow time exhibited lower segregation resistance.

This paper presents an assessment of the challenges faced and lessons learned during the transfer from the laboratory development to mass production for field implementation of High-strength Self-consolidated Lightweight Concrete (HSSCLWC).The evaluation included mechanical properties, workability, Rapid Chloride Penetration testing, and Scanning Electron Microscope images. Due to the difference in material performance depicted by the difference in microstructural features and durability aspects, structural performance of elements casted will not necessarily follow predicted behavior although they have the same compressive strength. Moreover, although the λ factor is introduced to realize the reduction of tensile properties of lightweight concrete compared to normal weight concrete, it was found that due to the difference in handling and mix preparation, the λ factorbecomes more inexact at capturing actual performance.

Palm oil fuel ash (POFA) has previously been used as a partial cement replacement in concrete. However, limited research has been undertaken to utilize POFA in high volume in concrete. This paper presents a study on the treatment and utilization of POFA in high volume of up to 50% by weight of cement in self-consolidating high strength concrete (SCHSC). POFA was treated via heat treatment to reduce the content of unburned carbon. Ordinary Portland cement was substituted with 0%, 10%, 20%, 30%, and 50% treated POFA in SCHSC. Tests have been conducted on the fresh properties, such as filling ability, passing ability and segregation resistance, as well as compressive strength, drying shrinkage and acid attack resistance to check the effect of high volume treated POFA on SCHSC. The results revealed that compared to the control concrete mix, the fresh properties, compressive strength, drying shrinkage, and resistance against acid attack have been significantly improved. Conclusively, treated POFA can be used in high volume as a cement replacement to produce SCHSC with an improvement in its properties.

Link to full text journal articles :
http://www.mdpi.com/1996-1944/8/5/2154/pdf

The use of self-consolidating concrete (SCC) containing recycled concrete aggregate (RCA) considerably increased in sustainable structural applications and civil engineering works. However, current literature and construction practices are not clear regarding the influence of RCA additions and presence of steel reinforcement on formwork pressure exerted by the plastic concrete. This paper reports experimental data obtained from 32 SCC mixtures possessing different stability levels and cast in 1.6-m high formwork containing various combinations of vertical and transverse steel bars. Test results have shown that mixtures incorporating recycled aggregates exhibited reduced initial maximum pressure, given the higher RCA surface roughness that promotes internal friction and material build-up at rest. The decrease in pressure was particularly accentuated in presence of steel bars, suggesting that the reinforcement cage confines the plastic concrete and carries part of its load. The transverse steel was around 1.5-times more influential than vertical steel in reducing the formwork pressure. The rates of pressure drop over time were not altered because of steel, implying that pressure decay is governed by the concrete intrinsic properties such as thixotropy, RCA friction, and cement hydration. Special emphasis was placed to develop regression models and examine suitability of existing ones to predict lateral pressure of RCA-modified SCC cast in formworks containing reinforcing bars.

This paper reports the composition and properties of highly flowable selfconsolidating concrete (SCC) mixtures made of high proportions of cement replacement materials such as fly ash and pulverized limestone instead of high dosage of a plasticizing agent or viscosity-modifying chemical admixtures. Self-consolidating concrete mixtures

Systematic, well-designed research provides the most effective approach to the solution of many problems facing highway administrators and engineers. Often, highway problems are of local interest and can best be studied by highway departments individually or in cooperation with their state universities and others. However, the accelerating growth of highway transportation develops increasingly complex problems of wide interest to highway authorities. These problems are best studied through a coordinated program of cooperative research. In recognition of these needs, the highway administrators of the American Association of State Highway and Transportation Officials initiated in 1962 an objective national highway research program employing modern scientific techniques. This program is supported on a continuing basis by funds from participating member states of the Association and it receives the full cooperation and support of the Federal Highway Administration, United States Department of Transportation. The Transportation Research Board of the National Academies was requested by the Association to administer the research program because of the Board's recognized objectivity and understanding of modern research practices. The Board is uniquely suited for this purpose as it maintains an extensive committee structure from which authorities on any highway transportation subject may be drawn; it possesses avenues of communications and cooperation with federal, state and local governmental agencies, universities, and industry; its relationship to the National Research Council is an insurance of objectivity; it maintains a full-time research correlation staff of specialists in highway transportation matters to bring the findings of research directly to those who are in a position to use them. The program is developed on the basis of research needs identified by chief administrators of the highway and transportation departments and by committees of AASHTO. Each year, specific areas of research needs to be included in the program are proposed to the National Research Council and the Board by the American Association of State Highway and Transportation Officials. Research projects to fulfill these needs are defined by the Board, and qualified research agencies are selected from those that have submitted proposals. Administration and surveillance of research contracts are the responsibilities of the National Research Council and the Transportation Research Board. The needs for highway research are many, and the National Cooperative Highway Research Program can make significant contributions to the solution of highway transportation problems of mutual concern to many responsible groups. The program, however, is intended to complement rather than to substitute for or duplicate other highway research programs.

The effects of coarse recycled concrete aggregate on freeze-thaw resistance, mechanical performance and transport properties of self-consolidating concrete (SCC) were investigated. Recycled concrete aggregate (RCA) was substituted for crushed coarse limestone aggregate as 0, 20, 40 and 60 wt% of limestone aggregate. Mixtures having three different water/binder (w/b) ratios (0.43, 0.48 and 0.53) were prepared. The properties of fresh concrete were determined by using the slump-flow, V-funnel and L-box tests. Compressive and splitting tensile strength, ultrasonic pulse velocity (UPV), water absorption, water sorptivity, chloride-ion penetration and freeze-thaw resistance of hardened concrete were determined. Test results indicate that in RCA containing mixtures, the viscosity of the SCC mixtures increased significantly. The compressive strength of SCC mixtures improved slightly with increasing the coarse RCA content up to 40%. In addition, water absorption and chloride-ion penetration of SCC mixtures increased slightly by the incorporation of RCA. On the other hand, the splitting tensile strength, unit weight, UPV, water sorptivity and freeze-thaw resistance of concrete decreased in RCA containing mixtures.

The effects of coarse recycled concrete aggregate on freeze–thaw resistance, mechanical performance and
transport properties of self-consolidating concrete (SCC) were investigated. Recycled concrete aggregate
(RCA) was substituted for crushed coarse limestone aggregate as 0, 20, 40 and 60 wt% of limestone aggregate.
Mixtures having three different water/binder (w/b) ratios (0.43, 0.48 and 0.53) were prepared. The
properties of fresh concrete were determined by using the slump-flow, V-funnel and L-box tests. Compressive
and splitting tensile strength, ultrasonic pulse velocity (UPV), water absorption, water sorptivity,
chloride-ion penetration and freeze–thaw resistance of hardened concrete were determined. Test results
indicate that in RCA containing mixtures, the viscosity of the SCC mixtures increased significantly. The
compressive strength of SCC mixtures improved slightly with increasing the coarse RCA content up to
40%. In addition, water absorption and chloride-ion penetration of SCC mixtures increased slightly by
the incorporation of RCA. On the other hand, the splitting tensile strength, unit weight, UPV, water sorptivity
and freeze–thaw resistance of concrete decreased in RCA containing mixtures.

This paper reports the composition and properties of highly flowable selfconsolidating concrete (SCC) mixtures made of high proportions of cement replacement materials such as fly ash and pulverized limestone instead of high dosage of a plasticizing agent or viscosity-modifying chemical admixtures. Self-consolidating concrete mixtures

Abstract Using glass powder to manufacture eco-friendly self-consolidating concrete (SCC) has been developed and improved in recent years. While researchers have determined the effect of glass powder on rheological properties of the green concretes, the sensitivity of SCC to this powder content yet remains to be investigated. This study introduced the concepts of insensitive design, and subsequently, the ranges of water to powder ratio, sodium lignosulfonate plasticizer (LS), and glass powder were determined and optimized by the artificial neural network and particle swarm optimization, respectively. The results showed the possibility of producing SCC with the least possible sensitivity to water, glass powder, and plasticizer variations. The best water to cement ratio to design an insensitive SCC derived between 0.33 and 0.34, but the reduction in the compressive strength was inevitable for the augmented water-to-cement ratio. The effect of glass powder on alkali-silica reactions (ASR) and compressive strength was also investigated to clear the way for the incorporation of glass powder in SCC. The results indicated that the ASR reduced to 52% by substituting 30% glass powder.

Concrete cylinders measuring 100 mm in diameter and 200 mm in height with a centrally placed 20 mm diameter reinforcing bar were used to study the effects of the corrosive environment on bond behavior of embedded reinforcements in SCLWC-based concrete mixtures included Metakaolin (MK) at the low volumes (2% and 4% by weight of total cementitious materials) together with Fly Ash (FA) (12% and 10%, respectively). 5% NaCl solution was used as a corrosive environment. For the duration of testing, 0.05 A of direct current was applied for accelerated corrosion.

Self-compacting concrete (SCC) which can be compacted into every corner of a formwork, purely by means of its own weight and without the need for vibrating compaction. The method for achieving self-compacting involves not only high deformability of paste or mortar, but also resistance to segregation between coarse aggregate and mortar when the concrete flows through the confined zone of reinforcing bars. Many concrete structure projects have been done in Taiwan using SCC by DMDA method, one of them is Nanggang project. DMDA method can create high density and high design strength with low water and cement content to achieve the high cement strength efficiency. With the water-to-cement ratio is higher than 0.42, water content is less than 160 kg/m3 and cement content is less than f’c/20, the stability of SCC’s volume can be controlled then the high physical density, high flowability and high homogeneity can be achieved. In 14 days after SCC making, the designed strength of 350 kgf/cm2 had been exceeded. High durability of SCC had been achieved in 365 days after making, with 4305 meter/seconds in ultrasonic test and 210 kΩ.cm in electrical resistivity.

The type and amount of filler are amongst the most important parameters influencing rheological, mechanical and durability characteristics of self consolidating concrete (SCC). Influence of using a limestone powder, the filler portion of reactive basalt filler and a type of class C fly ash on the fresh properties, alkali silica reactivity and transport properties were investigated in this study. For this purpose, six SCC mixtures having three filler types and two water/powder ratios were prepared. Alkali-silica reactivity was evaluated by conducting RILEM AAR-3 (38°C) and AAR-4 (60°C) concrete prism tests. Besides, the mixtures were exposed to permeable void content, sorptivity and chloride ion permeability tests in order to evaluate the transport properties. According to the results, using a high amount of powder from a reactive basalt in SCC mixture led to the highest expansion level and poor transport properties.

The sand is an inert element essential in the composition of concrete; its use ensures granular continuity between the cement and gravel for better cohesion of concrete. This paper presents the results of a study that investigated the influence of sand quality on the properties of fresh and hardened self-compacting concrete (SCC). The dune sands are very fine materials characterized by a high intergranular porosity, high surface area and low fineness modulus; on the other hand crushed (manufactured) sand has a high rate into thin and irregular shapes which are influencing the workability of concrete. The amount of dune sand varies from (0% 50%, to 100%) by weight of fine aggregates. The effect of additions is also treated (blast furnace slag and lime stone) The results show that the rheological properties favour the use of dune sands; however the mechanical properties support the use of crushed sand.

Abstract The type and amount of filler are amongst the most important parameters influencing rheological, mechanical and durability characteristics of self consolidating concrete (SCC). Influence of using a limestone powder, the filler portion of reactive basalt filler and a type of class C fly ash on the fresh properties, alkali–silica reactivity and transport properties were investigated in this study. For this purpose, six SCC mixtures having three filler types and two water/powder ratios were prepared. Alkali–silica reactivity was evaluated by conducting RILEM AAR-3 (38 °C) and AAR-4 (60 °C) concrete prism tests. Besides, the mixtures were exposed to permeable void content, sorptivity and chloride ion permeability tests in order to evaluate the transport properties. According to the results, using a high amount of powder from a reactive basalt in SCC mixture led to the highest expansion level and poor transport properties.

The effects of coarse recycled concrete aggregate on freeze–thaw resistance, mechanical performance and transport properties of self-consolidating concrete (SCC) were investigated. Recycled concrete aggregate (RCA) was substituted for crushed coarse limestone aggregate as 0, 20, 40 and 60 wt% of limestone aggregate. Mixtures having three different water/binder (w/b) ratios (0.43, 0.48 and 0.53) were prepared. The properties of fresh concrete were determined by using the slump-flow, V-funnel and L-box tests. Compressive and splitting tensile strength, ultrasonic pulse velocity (UPV), water absorption, water sorptivity, chloride-ion penetration and freeze–thaw resistance of hardened concrete were determined. Test results indicate that in RCA containing mixtures, the viscosity of the SCC mixtures increased significantly. The compressive strength of SCC mixtures improved slightly with increasing the coarse RCA content up to 40%. In addition, water absorption and chloride-ion penetration...

The feasibility of self-consolidating concrete (SCC) containing recycled concrete aggregate (RCA) was demonstrated in structural civil engineering applications. Yet, limited information exists regarding the effect of RCA additions, especially in presence of steel reinforcement, on lateral pressure exerted on formworks. This paper reports experimental data obtained from twenty-one SCC mixtures cast in 200 × 400 × 1600-mm formwork containing up to 4.71% vertical steel (the spacing between transverse steel was set to 450 mm). Test results have shown that mixtures incorporating RCA exhibited reduced initial pressure, which was mostly attributed to higher aggregate surface roughness that increases internal friction. The decrease in pressure was accentuated with the increase in vertical steel density, suggesting that the reinforcement cage confines the plastic concrete and carries part of its load. Special emphasis was placed to develop conservative reinforcement indices for appropriate prediction of SCC pressure, as well as propose modifications for existing models to account for the effect of RCA additions and presence of vertical steel bars.

Self-consolidating concrete, also known as self-compacting concrete (SCC), is a highly flowable concrete that spreads into place and fills formwork without the need for mechanical vibration. SCC reduces the time and labor cost needed for concrete placement. This study is part of the proposed project by Tennessee Department of Transportation (TDOT) carried out by University of Tennessee at Chattanooga (UTC) to develop four new SCC mixtures (two Class P-SCC (precast) and two Class A-SCC (general use), and insure they meet the minimum strength and durability requirements for TDOT Class P and Class A mixtures. The objectives of the study are to analyze effects of visual stability index (VSI) on both fresh and hardened properties of Class P-SCC concrete under the accelerated curing condition. In addition, the relationship between VSI and fresh segregation of SCC is investigated. A total of 24 concrete mixtures varying in VSI values were produced for the study. Different sizes of coarse aggregates materials were used during the mixing process, as well as different kinds of sands. A number of fresh and hardened properties tests were performed on the concrete mixtures to assess the performance of the mixes. The SURE CURE system is used to accelerate the curing process of the concrete. Finally, the results of this study are analyzed according to the coarse aggregate sizes and evaluated to recommend performance specifications for Class P-SCC for TDOT adoption of SCC standard operating procedures of the precast elements.

This paper aim to study the improve the impact resistance of concrete by using hemp fiber with (1%, 1.5%, 2%) as volumetric percentage and also by adding 10% of the Iraqi Bauxite as a pozzolanic material as partial replacement by weight of cement. The test that included in this study was Compressive strength, flexural strength, ultrasonic pulse velocity test and Impact Resistance.
Test results showed that concrete reinforced with hemp fiber and containing bauxite as a pozzolanic material showed increase in low velocity impact resistance with increase around 506% with in age of 90 days.

The type and amount of filler are amongst
the most important parameters influencing rheological,
mechanical and durability characteristics of self consolidating
concrete (SCC). Influence of using a limestone
powder, the filler portion of reactive basalt filler
and a type of class C fly ash on the fresh properties,
alkali–silica reactivity and transport properties were
investigated in this study. For this purpose, six SCC
mixtures having three filler types and two water/
powder ratios were prepared. Alkali–silica reactivity
was evaluated by conducting RILEM AAR-3 (38 C)
and AAR-4 (60 C) concrete prism tests. Besides, the
mixtures were exposed to permeable void content,
sorptivity and chloride ion permeability tests in order
to evaluate the transport properties. According to the
results, using a high amount of powder from a reactive
basalt in SCC mixture led to the highest expansion
level and poor transport properties.

Self-compacting concrete (SCC) which can be compacted into every corner of a formwork, purely by means of its own weight and without the need for vibrating compaction. The method for achieving self-compacting involves not only high deformability of paste or mortar, but also resistance to segregation between coarse aggregate and mortar when the concrete flows through the confined zone of reinforcing bars. Many concrete structure projects have been done in Taiwan using SCC by DMDA method, one of them is Nanggang project. DMDA method can create high density and high design strength with low water and cement content to achieve the high cement strength efficiency. With the water-to-cement ratio is higher than 0.42, water content is less than 160 kg/m3 and cement content is less than f’c/20, the stability of SCC’s volume can be controlled then the high physical density, high flowability and high homogeneity can be achieved. In 14 days after SCC making, the designed strength of 350 kgf/cm2 had been exceeded. High durability of SCC had been achieved in 365 days after making, with 4305 meter/seconds in ultrasonic test and 210 kΩ.cm in electrical resistivity.

This study was intended to evaluate the influence of hauling time on fresh self-consolidating concretes (SCCs) made with slump flows of 508, 635, and 711 mm (20, 25, and 28 in.). Nine different hauling times—10, 20, 30, 40, 50, 60, 70, 80, and 90 minutes—were used. Fresh performance of the selected SCCs was affected by hauling time in the form of loss in flowability and gain in flow rate and dynamic stability. A remediation technique consisting of admixture overdosing was able to revert the adverse influence of hauling time on the fresh characteristics of the selected matrices, as it produced SCCs with similar flow characteristics, dynamic stability, and passing ability to those obtained at the reference hauling time.

Abstract Using glass powder to manufacture eco-friendly self-consolidating concrete (SCC) has been developed and improved in recent years. While researchers have determined the effect of glass powder on rheological properties of the green concretes, the sensitivity of SCC to this powder content yet remains to be investigated. This study introduced the concepts of insensitive design, and subsequently, the ranges of water to powder ratio, sodium lignosulfonate plasticizer (LS), and glass powder were determined and optimized by the artificial neural network and particle swarm optimization, respectively. The results showed the possibility of producing SCC with the least possible sensitivity to water, glass powder, and plasticizer variations. The best water to cement ratio to design an insensitive SCC derived between 0.33 and 0.34, but the reduction in the compressive strength was inevitable for the augmented water-to-cement ratio. The effect of glass powder on alkali-silica reactions (ASR) and compressive strength was also investigated to clear the way for the incorporation of glass powder in SCC. The results indicated that the ASR reduced to 52% by substituting 30% glass powder.

This paper aims at investigating the phenomenon of macro-cell corrosion in the reinforcing steel of repaired chloride-contaminated self compacting concrete (SCC) patches. Self consolidating concrete because of its workability and stability is now a centre of focus among researchers and engineers working in the field of construction and repairs. Few researchers found SCC as a good repair material then ordinary concrete. But the literature and research relating to the repair of SCC concrete structures patches is limited. Therefore, thorough research has been carried in this paper to investigate the above said phenomenon. In this research, four prismatic specimens with two sets of 5 % and 3 % chloride contaminated SCC at the two ends were prepared respectively and the middle portion of these specimens was cast after 24 hours with uncontaminated SCC simulating the actual patch repair in the field; repaired due to chloride induced corrosion. From the six months experiment results of corr...

The sand is an inert element essential in the composition of concrete; its use ensures granular continuity between the cement and gravel for better cohesion of concrete. This paper presents the results of a study that investigated the influence of sand quality on the properties of fresh and hardened self-compacting concrete (SCC). The dune sands are very fine materials characterized by a high intergranular porosity, high surface area and low fineness modulus; on the other hand crushed (manufactured) sand has a high rate into thin and irregular shapes which are influencing the workability of concrete. The amount of dune sand varies from (0% 50%, to 100%) by weight of fine aggregates. The effect of additions is also treated (blast furnace slag and lime stone) The results show that the rheological properties favour the use of dune sands; however the mechanical properties support the use of crushed sand.

The sand is an inert element essential in the composition of concrete; its use ensures granular continuity between the cement and gravel for better cohesion of concrete. This paper presents the results of a study that investigated the influence of sand quality on the properties of fresh and hardened self-compacting concrete (SCC). The dune sands are very fine materials characterized by a high intergranular porosity, high surface area and low fineness modulus; on the other hand crushed (manufactured) sand has a high rate into thin and irregular shapes which are influencing the workability of concrete. The amount of dune sand varies from (0% 50%, to 100%) by weight of fine aggregates . The effect of additions is also treated ( blast furnace slag and lime stone ) The results show that the rheological properties favour the use of dune sands; however the mechanical properties support the use of crushed sand.

Self-compacting concrete (SCC) is a flowable type of concrete where minimum energy is required to form a structural component.
The high flow of SCC enables reduction in the number of workers, casting time, noise pollution and elimination of vibration.
Special mix design and the flowing nature of the concrete can change early age properties such as the lateral pressure on formwork
and shrinkage characteristics. This paper presents the background to SCC and discusses in detail the main aspects related to
formwork pressure and early age shrinkage of current SCC formulations.