Control Self-compacting Concrete Research Articles

Flexural Behaviour and Durability of Self Compacting Concrete Mixed with SN-Based Corrosion Inhibitor

The present study aimed to create a Self-Compacting Concrete (SCC) that possesses long-lasting properties and evaluate its fresh, mechanical, and durability properties by substituting 30% of the cement with class F fly ash. Furthermore, the performance of SCC that has been admixed with an SN-based corrosion inhibitor was investigated. Various factors such as the ratio of water to powder, fine aggregate, coarse aggregate (12mm downgraded), and the SN-based corrosion inhibitor were studied. The particle size distribution of the materials was analyzed using a sieve to achieve an even distribution of sizes, appropriate packing, and a lower void content. Multiple mixes were conducted, each with a unique combination of fine and coarse aggregate, as well as a water-to-powder ratio that was altered to optimize the mix percentage. Finally, controlled SCC (or mix M2) met the fresh property standards outlined in the EFNARC guidelines and specifications.The mechanical and durability properties of control SCC and SCC admixed with an SN-based corrosion inhibitor were investigated. Results showed a significant improvement in the compressive strength, split tensile strength, and flexural behavior of Reinforced Cement Concrete (RCC) beams when control SCC was utilized. Furthermore, the SCC with 2% SN demonstrated superior performance in terms of chloride penetration compared to the control SCC. The flexural strength parameters of the SCC with 2% SN were comparable to those of the control SCC. Based on the study's findings, it can be concluded that the addition of inhibitors at a weight percentage of 2% of the cement supplied increased durability properties without affecting the strength properties of SCC. Therefore, the created durable SCC can be recommended for applications such as bridges, prefabricated constructions, and deck slabs which are densely crowded with steel rebars. The study's findings could contribute to the development of SCC with enhanced properties, which would lead to more durable and sustainable construction materials.

Time-depth dependent chloride diffusion coefficients of self-compacting concrete

Chloride attack severely impacts the performance of reinforced concrete. The total and free chloride ion concentrations (CICs) of self-compacting concrete (SCC) prepared with three supplementary cementitious materials (SCMs) - fly ash (FA), blast furnace slag (BS), and silica fume (SF) – were measured through the accelerated salt immersion tests. The apparent chloride diffusion coefficients (CDCs) at any exposure time and erosion depth were calculated using the Boltzmann-Matano method. The influence of the type and content of SCMs, the water-binder ratio (W/B), and the type of salt solution on CICs and CDCs were investigated. Both introducing SCMs and reducing W/B effectively reduced the CIC. The SCM that most effectively reduced CIC was SF, followed by BS and then FA. Free CICs were reduced to a greater degree than total CICs in FA and BS concrete, but the opposite was true for SF concrete. Presence of calcium chloride in salt solution increased total CICs while reducing free CICs. Apparent free CDC dropped over exposure time and initially increased with erosion depth but eventually stabilized. A model of apparent free CDC considering the time-depth dependence was created, which shows that time reduction factors of CDC is larger in SCM-containing SCC than in control SCC.

Impact and durability properties of alccofine-based hybrid fibre-reinforced self-compacting concrete

Many research works have already been made and are still in progress on metallic fibres, as their incorporation reduces the brittleness of the concrete and improves its resistance to the impact and crack propagation. But the use of such non-metallic fibres may induce corrosion which is a major problem to be addressed from the durability aspect. To overcome this problem, in the present research work, a non-metallic hybrid fibre combination was investigated with synthetic fibres like polypropylene and abaca fibres. Also, rather than using conventional cementitious materials such as silica fume, fly ash, and ground granulated blast furnace slag, a new generation of ultra-fine material namely alccofine was used as a partial replacement for the cement by 15%. Abaca fibre was utilised in a constant addition of 0.5% and blended with polypropylene fibre in a range varying from 0% to 2% with an increment of 0.5%. The fresh properties of self-compacting concrete (SCC) in mono and hybrid fibres combinations were assessed through slump flow, J-ring, and V-funnel tests. Water absorption and sorptivity tests were conducted to ensure the durability of the prepared mix. Further, impact tests were carried out on the prepared cylinder specimens to check the capability of the mix with the non-metallic hybrid combination. The main objective here was to check whether a high-strength durable SCC could be achieved using non-metallic fibres and natural fibres. From the obtained experimental results, it was observed that 15% alccofine as a partial substitute to the cement with the addition of 0.5% of abaca fibre and 2% of polypropylene fibre to SCC performed better than the control SCC.

Properties of Self-Compacting Concrete Containing Palm Oil Fuel Ash and Rice Husk Ash

Palm fuel ash (POFA) and rice husk ash (RHA) are usually disposed to open areas and landfills without treatment, resulting in environmental problems. Both materials fulfilled the criteria as pozzolanic material, thus can be used as substitutes to cement. This paper presents the comparison in the fresh and hardened properties between self-compacting concrete (SCC) containing POFA and RHA. The SCC mixtures were produced based on water/binder ratio of 0.6. Both POFA and RHA were introduced in concrete replacing 0%, 10%, 20% and 30% of cement by weight. The fresh SCC was tested for three (3) fresh properties including filling ability, passing ability and segregation resistance. Meanwhile, the hardened properties of concrete were tested for its compressive strength. The fresh properties of SCC incorporating POFA and RHA fulfilled all the requirements of SCC which include the filling ability, passing ability and segregation resistance. Meanwhile, SCC containing RHA had higher compressive strength than the SCC containing POFA for all different replacement level. This is because RHA had higher SiO2 content than POFA, thus promote more pozzolanic reaction to improve the strength of concrete. Furthermore, the optimum replacement level of POFA and RHA in SCC are 10% and 20%, respectively. However, the compressive strength of both SCC containing POFA and RHA were still lower than the control SCC. It is suggested that the SCC containing POFA and RHA to be cured for longer period to achieve better or equivalent strength to the control SCC.

Rheological behaviour, hydration, and microstructure of self-compacting concrete incorporating ground ferronickel slag as partial cement replacement

Self-compacting concrete (SCC) is a special type of concrete which has some additional requirements beyond those of traditionally vibrated concrete, such as high flowability and consolidation by self-weight without any segregation of the ingredients. In this research, the production of SCC has been investigated by utilizing a metallurgical by-product, namely ferronickel slag (FNS) to enhance the green supply chain in concrete industry. FNS at 40% replacement of natural sand, and ground ferronickel slag (GFNS) at the rates of 0%, 20%, 35%, and 50% replacement of cement was used, and the rheological, hydration, strength, and microstructural development of SCC are presented in this paper. The fresh properties were assessed by rheology, slump flow, T50, V-funnel, J ring, L-box, U-box, and visual stability index tests. The heat of hydration was determined by isothermal calorimetry, and scanning electron microscope, energy dispersive x-ray spectroscopy, and x-ray powder diffraction techniques were used for microstructural analysis. The results were evaluated against the recommendations of the European and Japanese standards for SCC. Increases in fluidity and workability and decreases in yield stress and viscosity were observed with the increase in GFNS content. Delayed hydration heat was observed with the use of GFNS. The low calcium content of GFNS is attributed to this retardation. The 28 days compressive strength decreased from 79 MPa for the control mix by 16% due to 35% cement replacement by GFNS. This is considered reasonable due to the use of low-calcium GFNS as a cement replacement. The heterogeneous and porous morphology of the microstructure of GFNS incorporated SCC is ascribed to this decrement. Considering both fresh and hardened properties, the GFNS incorporated SCC mixtures are found comparable to the control SCC mixture. Therefore, FNS can be used as a promising alternative ingredient for SCC to strengthen the eco-friendly supply chain and sustainable waste management.

Effect of copper slag on recycled aggregate based self-compacting concrete

The present research paper investigated experimentally the effective use of copper slag (CS) in recycled aggregate based self-compacting concrete (SCC). The work is carried out in two series. In the first series SCC mixes are prepared with recycled coarse aggregate (RCA) as a replacement of natural coarse aggregate of various proportions (0%, 33%, 66% and 100%). In the second series copper slag of various proportions (0%, 20%, 40%, 60%, 80% and 100%) is incorporated as fine aggregate in SCC mix made with 33% RCA and studied the behaviour of recycled aggregate based SCC mixes. Different properties of all mixes including fresh and hardened properties were determined according to EFNARC guidelines and IS code of practice and compared with the control concrete. The morphology of various SCC mixes is examined through scanning electron micrograph to verify the strength of SCC mix. The test results revealed that, with increased in RCA content the compressive strength of SCC decreased whereas the tensile strength of SCC is found marginal and comparable to control mix. However, by incorporating copper slag to the recycled aggregate concrete the compressive and split tensile strength of SCC enhanced up to 7% and 28% respectively in comparison to control SCC mix. The cost-effective and environmental impact analysis of RCA based SCC was carried out and it is revealed that, the combined use of RCA and copper slag could cut the cost of SCC by 8–11% and the maximum reduction in CO2 emission was about 3% which enables the construction sector to develop more sustainably and make a significant contribution towards the preservation of natural resources.

Effect of granite industry waste addition on durability properties of fly ash blended self-compacting concrete

The continuous production of granite powder (GP) waste causes a deadly impact on environment and human life. This present study thus examines the impact of granite powder (GP) as substitute to natural fine aggregate (up to 60%) on compressive strength and durability properties of eco-friendly fly ash blended self-compacting concrete (SCC). Results revealed that strength enhanced on incorporation of up to 40% GP in concrete mixture than fly ash blended control mixture. Resistance against chloride, carbonation and corrosion improved for incorporation of up to 50% GP in concrete mixture than fly ash blended control mixture. Moreover, all the blended SCC mixtures, except SCC mixture containing 50% and 60% GP, showed higher compressive strength than ordinary Portland cement (OPC) based control SCC mixture at higher days of curing. Besides, all the blended SCC mixtures, except mixture containing 60% GP, showed better resistance against chloride, carbonation, drying shrinkage and corrosion than OPC based control SCC mixture. It was hence concluded that GP up to 50% as an alternative of fine aggregate could be positively incorporated in the production of eco-friendly fly ash blended SCC for the improvement of aforesaid durability properties (with little higher precaution against drying shrinkage).

Study of the properties in the fresh and hardened state of self-compacting lightweight concrete

The technology of Self-compacting Concrete (SCC) has brought great advancement to construction techniques, allowing significant growth in the use of concrete also combining with the technology of Lightweight Concrete (LWC). This study searched to demonstrate the performance of a Self-compacting Lightweight Concrete (SCLC), using expanded clay to replace conventional aggregates with structural strength that meets current Brazilian’s standards (ABNT). Two mixtures were produced: a) with total replacement of coarse aggregate and; b) with partial replacement of fine aggregate and total of coarse aggregate. The properties in the fresh and hardened states were evaluated. The SCLCs produced in this work showed a significant improvement in the properties of the fresh state, compared to the control SCCs. In the hardened state, despite the drop in resistance to mechanical stresses, it was possible to obtain a concrete with good efficiency factor, with density between 1,550 kg/m3 and 1,790 kg/m3 and compressive strengths between 25.0 and 35.0 MPa. It can also be concluded that the ratio of the modulus of elasticity by the axial compressive strength showed adequate linearity between the types of concrete evaluated.

Effect of GGBS and fly ash on mechanical strengthof self-compacting concrete containing glass fibers

In the era of building engineering the intensification of Self Compacting Concrete (SCC) is world-shattering magnetism. It has lot of rewards over ordinary concrete i.e., enrichment in production, cutback in manpower, brilliant retort to load and vibration along with improved durability. In the present study, the mechanical strength of CM-2 (SCC containing 10% of rice husk ash (RHA) as cement replacement and 600 grams of glass fibers per cubic meter) was investigated at various dosages of cement replacement by fly ash (FA) and GGBS. A total of 17 SCC mixtures including two control SCC mixtures (CM-1 and CM-2) were developed for investigating fresh and hardened properties in which, ten ternary cementitious blends of SCC by blending OPC+RHA+FA, OPC+RHA+GGBS and five quaternary cementitious blends (OPC+RHA+FA+GGBS) at different replacement dosages of FA and GGBS were developed with reference to CM-2. For constant water-cement ratio (0.42) and dosage of SP (2.5%), the addition of glass fibers (600 grams/m3) in CM-1 i.e., CM-2 shows lower workability but higher mechanical strength. While fly ash based ternary blends (OPC+RHA+FA) show better workability but lower mechanical strength as FA content increases in comparison to GGBS based ternary blends (OPC+RHA+GGBS) on increasing GGBS content. The pattern for mixtures appeared to exhibit higher workablity as that of the concentration of FA+GGBS rises in quaternary blends (OPC+RHA+FA+GGBS). A decrease in compressive strength at 7-days was noticed with an increase in the percentage of FA and GGBS as cement replacement in ternary and quaternary blended mixtures with respect to CM-2. The highest 28-days compressive strength (41.92 MPa) was observed for mix QM-3 and the lowest (33.18 MPa) for mix QM-5.

Performance of ternary blend SCC with ground granulated blast furnace slag and metakaolin

Self Compacting Concrete (SCC) is of immense use in the concrete industry where access was restricted for concreting and building components with congested reinforcements. In this paper, a sincere attempt was made to develop SCC using the ternary mix. Industrial waste namely Ground Granulated Blast furnace Slag (GGBS) (from 30 to 50%) and the other material Metakaolin (MK) (from 5 to 15%) was used as a replacement to cement in different combinations to produce SCC with better performance. In this present research paper, studies on X-ray diffraction, rheological and mechanical properties were studied for ternary SCC mix containing MK and GGBS. The ternary SCC mix (S1) containing 5% MK and 30% GGBS had shown improved compressive strength characteristics among ternary SCC mixes, control SCC and conventional vibrated concrete mixes. The ternary SCC mix (S7) also had higher tensile strength characteristics concerning control SCC and conventional vibrated concrete mixes.

Effect of Combined Supplementary Cementitious Materials on the Fresh and Mechanical Properties of Eco-Efficient Self-Compacting Concrete

Global concrete demand is causing depletion of natural resources at an alarming rate. Self-compacting concrete (SCC) is an innovative solution as it uses less aggregates; however, the drawback of SCC is that high cement content is required compared to conventional concrete. Considering that cement production emits 7% of carbon dioxide (CO2) gas emissions, the use of high content of cement in SCC production is concerning. Though the high powder content of SCC may be of a concern, however, it allows the opportunity to substitute the cement content with supplementary cementitious materials. This experimental work was therefore conducted to reduce the cement content by substituting it with waste materials, such as eggshell powder (ESP) and palm oil fuel ash (POFA), and develop an eco-efficient SCC. The cement content was partially substituted by 0 to 5% ESP and 0 to 15% POFA by weight of total binder. A total of 90 cubes of 100 mm and 60 cylinders of 100 × 200 mm dimension were prepared to evaluate the compressive and splitting tensile strengths, modulus of elasticity, and Poisson’s ratio. Furthermore, the environmental impact assessment was conducted to assess the embodied CO2 and eco-strength efficiency of the developed eco-efficient SCC. It was found that the combination of POFA and ESP increased pozzolanic reactivity, developing additional calcium silicate hydrate gels, thus increasing strength. The combination of 2.5% ESP and 5% POFA (a total of 7.5% cement substitution) was deemed to be the optimal combination as it provided better strength in SCC after 28 days of curing, which leads to 9.66% higher compressive strength than the control SCC. Furthermore, the developed SCC was observed to be eco-friendly as it reduced embodied carbon ranging from 3.86 to 15.33% and eco-efficiency ranging from 2.38 to 15.48% on 28 days compared to the control SCC.

Effect of recycled materials and hybrid fibers on the properties of self-compacting concrete

Self-compacting concrete (SCC) has many properties comparing to conventional concrete and represents a good choice towards sustainability. The use of different recycled materials contributes to seize the negative impact of huge amount of waste on the ecosystem. In this study, locally available materials have been used as partially cement replacements. Such materials including ceramic waste powder (CWP) and glass powder (GP) in addition to fly ash with total cement replacement of 30%(12%CWP+8%GP+12%Fly ash) have been found to increase the compressive strength by about 7% compared to the control SCC. Normal aggregate was replaced by recycled aggregate with different recycled aggregate which are Recycled Concrete (RC), Crushed red brick (REB) and Crushed ceramic (CER.) The percentages of replacements are: 25%, 50%, 75% and 100%, for each type of aggregate. The results show that the increase of the amount of recycled aggregates decreases the strength properties of SSC and effect on workability of SSC also the result show a reduction in oven dry density. The combination of different type of recycled aggregate shows a reduction in SSC strength. The use of fibers shows better performance of SSC compared to combination aggregate mix without fiber but reduce the workability of SCC. However, the fiber content of 1.0% shows the best result of the mechanical properties, whereas, fiber content up to 1.5% affects negatively on concrete properties. The use of hybrid fiber also increases the strength properties of concrete.

Modeling of Compressive Strength of Sustainable Self-Compacting Concrete Incorporating Treated Palm Oil Fuel Ash Using Artificial Neural Network

The utilization of a high-volume of treated palm oil fuel ash (T-POFA) as a partial cement substitution is one of the solutions presented to reduce carbon dioxide emissions (CO2) and improve concrete sustainability. In this study, the Adaptive Neuro-Fuzzy Inference System (ANFIS) is adapted as an artificial neural network (ANN) modeling tool to predict the compressive strength of self-compacting concrete (SCC) containing T-POFA. The ANFIS model has been developed and validated using concrete mixtures incorporating 0%, 10 wt%, 20 wt%, 30 wt%, 50 wt%, 60 wt%, and wt 70% T-POFA as a replacement of ordinary Portland cement (OPC) at a constant water/binder (W/B) ratio of 0.35. The experimental data were divided into 70% training data and 30% testing data. The experimental results of self-compacting concrete (SCC) containing T-POFA ensured comparable or higher compressive strengths, especially at later ages, when compared to the control SCC. However, the prediction results of the compressive strength of SCC samples using the ANFIS model are very close to the experimental values. The developed ANFIS model showed a highly-efficient performance to predict the SCC compressive strength. In addition, the obtained accurate predicted results using the developed ANN model will significantly affect the current experimental protocols, especially for costly and unsafe experiments.

Transport mechanisms as indicators of the durability of precast recycled concrete

The objective of this paper was to analyze the influence of crushed precast concrete waste on the transport mechanisms as indicators of the durability of precast recycled self-compacting concrete (SCC) as an alternative to the coarse fraction of natural aggregate. The replacement percentages were 20%, 50% and 100%, by weight, of the silica gravel 2/12.5 mm. Two types of SCC were manufactured: the first with a minimum compressive strength of 30 MPa (HR-30) and the second with a minimum strength of 45 MPa (HR-45). The recycled SCC’s mechanical characteristics such as compressive strength, splitting tensile strength, flexural strength and modulus of elasticity were analyzed. Regarding the physical properties related to transport mechanisms, the influence of the recycled aggregate on the porosity, absorption, penetration of water under pressure, density of hardened concrete and ultrasonic pulse velocity was analyzed. All these properties were compared with those of a control concrete. The results of the mechanical tests provide values close to those obtained for the control SCC, while, in terms of durability the results fulfil the limit values that are considered for a good quality concrete. Therefore, it can be concluded that the use of crushed precast concrete waste with different degrees of substitution is a viable alternative in the manufacture of more sustainable SCC.

Fresh and mechanical performance and freeze-thaw durability of steel fiber-reinforced rubber self-compacting concrete (SRSCC)

The self-compacting concrete (SCC) with the replacement of recycled rubber aggregates is limited for the field application due to high-performance requirements. The steel fiber was introduced to the rubberized SCC (RSCC) to enhance its performance and promote its application. The fresh and mechanical properties and durability performance of steel fiber-reinforced rubber self-compacting concrete (SRSCC) were evaluated. The SRSCC samples were prepared with replaced rubber aggregate based on fine aggregate volume percentages of 10%, 15%, and 25% and a consistent steel fiber ratio of 0.2%. The plain SCC and rubberized SCC samples were also produced for comparison. The fresh performance was evaluated with slump flow, J-ring flow, V-funnel, and U-box tests. The results showed that both filling and passing ability could be affected by the added steel fiber and rubber aggregate. However, the SRSCC could still meet most of the recommended criteria for passing and filling abilities when the rubber content is lower than 25%. Regarding the hardened properties, the compressive strength was reduced in rubber SCC samples with increased rubber contents by comparing with the control SCC samples. Nevertheless, SRSCC samples with 10% rubbers have higher splitting tensile strength than RSCC and plain SCC. Also, the SRSCC specimens showed excellent freeze-thaw resistance after 600 F-T cycles. The relative dynamic modulus of elasticity slightly increased without any dimensional expansion in SRSCC samples. In summary, the proposed SRSCC can meet required flowability, filling and passing abilities along with good mechanical and freeze-thaw performance. This study will provide lab test data for the applications of recycling waste tire aggregates in steel fiber-reinforced SCC.

Properties of steel fiber self-compacting concrete incorporating quarry dust fine powder

Self-compacting concrete (SCC) has great potentials as it offers several environmental, economic and technical benefits. Moreover, the use of fibers extends its possibilities since fibers arrest cracks and retard their propagation. Incorporation of Quarry Dust (QD) in SCC help to reduce environmental hazards during the production of QD. This study evaluated the fresh and hardened properties of steel fiber self-compacting concrete (SFSCC) incorporating QD. The optimum fiber and QD contents with no adverse effects on fresh and hardened properties were determined. A comparative study on behavior of SCC and SFSCC mixtures in terms of workability, compressive strength, compressive strength development ratio, tensile, flexural and energy absorption capacity was carried out. Test results showed that compressive strength increased with increase in QD contents at fixed fiber content by mass of Portland cement (PC) and then decreased. Strength development ratio (C28/C7) for SCC was 1.13, while it was 1.06, 1.08, 1.10 and 1.01 after reinforcing with 0.10, 0.20 and 0.30 contents of fiber. The compressive, tensile, flexural and energy absorption capacity or Toughness of SFSCC increased with the inclusion of the aforementioned contents of steel fiber up to 0.20 % volume of total binder at constant QD content and then decreased when compared with control SCC values. From these results, optimum value for the variables studied was obtained from mix QD20 + 0.2fr. Hence, steel fiber and QD could be successfully used in SCC production not minding the slight draw back on workability of SCC caused by inclusion of steel fiber, but with a modified dosage of super-plasticizer (SP), fresh and hardened properties, in accordance with specifications in relevant code(s) can be achieved.

Physical and mechanical properties of polymer modified self-compacting concrete (SCC) using natural and recycled aggregates

The study researched the effectiveness of four polymer admixtures (3%, 5%, 10%, and 15% of water weight) on the fresh and hardened properties of self-compacting concrete (SCC) cast using recycled and natural aggregates. Results show that polymer additives had positive effects on the fresh properties of SCC using recycled aggregates. Incorporating polymer additives increased the filling ability of concrete by more than four times. All polymer modified SCCs had a 100% passing ability compared to the 80% passing ability of the control samples. The compressive strength of materials at similar polymer ratios decreased by about 50% when natural aggregates were replaced with recycled aggregates. The flexural strength of SCC including recycled aggregates with 15% polymer was maintained compared to the control SCC including natural aggregates. The addition of 15% polymer to recycled aggregates concrete could improve workability and maintain flexural strength.

Investigation of SCC characterizations incorporating supplementary cementitious materials

An experimental study was performed to assess the effect of metakaolin (MK) as supplementary cementitious material (SCM) and limestone powder (LP) and nano-titanium dioxide (nano-TiO2; NT) as mineral admixtures on the pore structure, mechanical and durability of self-compacting concrete (SCC). The fresh-state performance was evaluated by slump flow, T 50, V-funnel and L-box tests, and hardened-state parameters were analyzed through compressive strength, water absorption, density and electrical resistivity. Furthermore, permeability was analyzed by means of the rapid chloride permeability test and mercury intrusion porosimetry. Using additives resulted in improvement of rheological properties and compressive strength. Additionally, the density and electrical resistivity of SCC mixes containing SCMs and NT were higher than those of the control SCC mixes. Low absorption and permeability values were obtained for the mixes containing 5% NT. The results herein reported suggest that replacement ratios of 15% MK, 10% LP and 5% NT can be considered as optimal from a cost–benefit point of view in terms of fresh- and hardened-state performance. Predictive models for the hardened properties analyzed have been obtained using artificial neural networks (ANNs). ANNs have been proven an appropriate alternative method for predicting the hardened properties of SCC mixes.

Strength properties and microstructural analysis of self-compacting concrete incorporating waste foundry sand

Waste Foundry Sand (WFS) is a solid waste generated from the metal casting industry. Globally, casting production is about 105 million metric tons per year, about 0.60 ton of WFS is produced per 1 ton of cast steel production. Hence, the yearly production of WFS is approximately 62.64 million metric tons. Therefore, disposal of WFS generated from the casting industry poses serious environmental problems. On the other hand, continuous extraction of natural resources is depleting the environment at a rapid pace increasing the cost of production due to an insufficiency of natural resources.This paper presents the results of an experimental investigation on the influence of waste foundry sand (WFS) as a fine aggregate replacement on the fresh, strength and micro-structural properties of self-compacting concrete (SCC). Initially, control SCC was designed and then, fine aggregates were replaced with 5, 10, 15, 20, 25 and 30% of WFS by volume. The fresh state properties of SCC were evaluated using slump flow, T500, V-funnel-box, and U-box test. Strength and microstructural investigations were carried up to the age of 365 days. Tests results indicate all concrete mixes exhibited the properties of fresh state SCC. The 28-day compressive strength of control SCC was 58 MPa. There was 6.38–18.76% reduction in the strength of SCC with the use of 5–30% WFS at 28 days. Micro-structural results of XRD and SEM validate the experimental results. Hence, WFS could be suitably used in the manufacturing of SCC.

Performance of self-compacting concrete comprising granite cutting waste as fine aggregate

Continuous stockpiling of granite industrial by-product enforced researchers to use this waste in a sustainable manner in concrete to reduce its adverse impacts on the ecosystem. Therefore, fresh and hardened properties of self-compacting concrete (SCC) containing granite cutting waste (GCW) were assessed in this study. The GCW was used at an increased step level replacement of 20% of fine aggregate (i.e. river sand) up to 100%. Slump flow, T500 time, V-funnel, L-box, and J-ring tests were performed to assess the fresh properties of SCC mixes, whereas, compressive strength, flexural strength, ultrasonic pulse velocity, water absorption and water permeability tests were conducted for measuring the hardened properties of SCC mixes. Results of fresh properties tests for all of the mixtures were found within the satisfactory limit as per EFNARC standard except the mix prepared with 100% GCW. The incorporation of GCW in SCC mixes showed an increment in the compressive and flexural strength at 20% replacement level and decrement in both strength characteristics beyond 20% replacement. Moreover, even at 40% replacement level, the flexural strength was found to be higher with respect to the control mix. The better impermeability characteristics and higher ultrasonic pulse velocity values of granite modified SCC mixtures were found up to 40% incorporation of GCW as compared to the control SCC mix. The scanning electron microscope and X-ray diffraction analysis also validated the results of hardened characteristics. Granite modified SCC mixtures showed satisfactory performance during fresh and hardened characteristics test, it was therefore inferred that GCW could be used efficiently to engender sustainable SCC mixes.