Slump Flow Test Research Articles

Effects of Mica and Feldspar as partial cement replacement on the rheological, mechanical and thermal durability of self-compacting mortars

In this experimental study, the impacts of replacing cement by Mica and Feldspar on rheological, mechanical and thermal durability of self-compacting mortars (SCMs) are investigated. The cement was partially replaced by Mica and Feldspar at the substitution rates of 10%, 20% and 30%. In general, 14 mix designs of SCMs were considered in two series with w/b ratios of 0.4 and 0.3. For assessment of rheological properties, mini-cone slump flow test and mini V-funnel tests were performed. The compressive strengths after 3, 7, 28 and 90 days of curing, and the 28-day flexural strength were obtained. All mixes were subjected to water absorption and sorptivity tests. For investigating the thermal durability, residual compressive strength after high-temperature exposure at 600 °C were investigated. Also, the microstructure of specimens was assessed by using Scanning Electron Microscope (SEM) images. The results indicated that all the SCM mixes containing Mica and feldspar with different w/b ratios had acceptable rheological properties considering EFNARC criteria. Mechanical properties were slightly decreased by Mica and Feldspar replacement, and the mixes containing Feldspar showed higher mechanical properties in comparison with mixes containing Mica. Replacing the cement by Mica and Feldspar decreased the sorptivity coefficient of SCMs and remarkably improved the thermal durability. Mix designs contained 20% of Mica showed the maximum residual compressive strengths after high temperature exposure in both w/b ratios.

Influence of waste glass aggregates on the rheological properties of self-consolidated concrete

ABSTRACT Implementation of self-consolidating concrete (SCC) leads to the evaluation of more attractive, quality-controlled concrete with improved workability in the construction sector. The aim of the paper involves the determination of the rheological properties of SCC using waste glass aggregate, which affects the concrete’s rheological behaviour. In this research, the conventional coarse aggregate was substituted by the waste glass aggregate (WGA), at 10%, 20% and 30%, respectively. The consequence of adding waste glass in fresh concrete was inspected by several tests such as density, slump flow, J-ring, L-box and V-funnel test. These properties were then compared to the corresponding properties of normal-weight concrete. Test results specify that the WGA amplified the slump value of SCC thus indicates the improved workability. The decreasing density of the SCC leads it to the lightweight concrete. Subsequently, the SCC concrete shows relatively reduction in the passing ability with the addition of waste glass due to the angular shape of the glass bits. Hence, the study concludes that all of the rheological properties of self-compacting glass concrete (SCGC) made of WGA showed an impressing enhancement in the result, in comparison with the conventional SCC.

INVESTIGATION OF EFFECTS OF RECYCLED AGGREGATES AND BLAST FURNACE SLAG ON PROPERTIES OF SELF-COMPACTING CONCRETE

The effects of simultaneous use of recycled aggregates and ground blast furnace slag as a percentage of cement-constituting materials on different properties of fresh self-compacting concrete (SCC) are investigated in this study. To this end, three series of SCC mixtures with a fixed volume of cement paste equalling 380 ltr/m3 (2.36 gal/ft3) and the replacement ratio of coarse aggregates (fifty percent and one hundred percent) and total aggregates (zero percent, fifty percent and one hundred percent) were prepared. The water content ratios in the first, second and third series were 0.4, 0.45, and 0.5, respectively. The results of the compressive strength tests for 7-day, 14-day and 28-day cubic specimens and compressive strength and Brazilian test results for 28-day cylindrical specimens were used as control parameters governing the SCC resistive quality. The results of fresh SCC tests (including slump-flow and T50 tests, V-funnel test, and L-box test) showed that the negative effect of recycled fine aggregates on fresh SCC properties is significantly more than that of recycled coarse aggregate. However, recycled SCC with acceptable properties can be obtained with a slight increase in the amount of superplasticisers used in the presence of slag.

Workability, fiber distribution, and mechanical properties of UHPC with hooked end steel macro-fibers

Ultra high-performance concrete (UHPC) has superior mechanical and durability performance, which has motivated researchers and engineers to extensively explore its applications in civil engineering. While straight steel micro-fibers are frequently adopted to reinforce UHPC in existing engineering applications, studies have reported that deformed steel macro-fibers outperform straight steel micro-fibers in terms of enhancing the post-peak response and ductility of UHPC, which is of critical importance in seismic resistant design and applications. However, there lingers a major concern regarding the workability of deformed steel macro-fiber reinforced UHPC. Therefore, a thorough investigation was performed in this study to address this issue. A series of tests were carried out to study the effect of silica sand and fiber contents on the performance of fresh UHPC, including restricted and non-restricted deformability, filling ability, horizontal and vertical velocities, passing ability, and fiber distribution. In addition to the workability, the influences of silica sand and fiber contents on the compressive and tensile behavior of UHPC with deformed steel macro-fibers at 28 and 90 days were investigated. The results indicated that although a higher silica sand content led to an improved workability for UHPC, it reduced the homogeneity of fiber distribution. Furthermore, the inclusion of a 1% volume fraction of deformed steel macro-fibers was found to improve the workability of UHPC but reduced the compressive strength, which was contrary to the effect of straight steel micro-fibers at the same volume fraction. Increasing the fiber content from 1% to 2% increased the plastic viscosity of UHPC, which improved the fiber distribution and alleviated the blocking effect of steel bars. The use of the standard slump flow test with the criteria suggested by ACI 237R was a feasible approach to evaluate the fiber distribution and passing ability of UHPC with hooked end steel macro-fibers. Overall, the UHPC reinforced with a 2% volume fraction of deformed steel macro-fibers had good workability and fiber distribution when its plastic viscosity was adequately controlled.

Comparative Fracture Properties of Four Fibre Reinforced High Performance Cementitious Composites.

This study investigates the fracture properties of high performance cementitious composites (HPCC) with four different types of fibres and with volume fraction content 3%. The four fibres are steel hooked end (S), polypropylene crimped (PP), basalt chopped (B), and glass (G) fibres. The tests were carried out in accordance with the RILEM recommendations. In order to examine the fresh properties of HPCC the slump flow tests were performed. Twelve fibre reinforced HPCC beam specimens with notch were cast and tested using central point loading experiments. In addition, experimental tests of the compressive strength and splitting tensile strength were carried out. The test results made it possible to obtain representative fracture parameters, such as the equivalent strengths, residual strengths, and fracture energy of fibre reinforced HPCC. The S fibre specimens showed the best performance in terms of workability, compressive strength, tensile splitting strength, and fracture energy at large deflection. On the other hand, G fibre specimens exhibited the best performance in terms of flexural strength, equivalent flexural strength at higher deflection, and residual flexural strength at lower deflection. In terms of equivalent flexural strength at lower deflection and residual flexural strength at higher deflection, basalt fibre specimens performed the best. On the contrary, polypropylene fibre reinforced beam specimens revealed the highest deflection capacity.

Farklı Mineral Katkılı Kendiliğinden Yerleşen Betonların Taze ve Sertleşmiş Özellikleri

Self-compacting concrete (SCC) is developed with the idea of improved flowability of the fresh concrete mixture. The new technology in plasticizing agents and special mix design of concrete has given this opportunity without any segregation and bleeding. In addition to ease of placement, reduction in the construction time, labor costs and construction noise are the other benefits of SCC. The aim of this study is to investigate the fine mineral additive effect on the fresh and hardened properties of the SCC. For this reason, ground granulated blast furnace slag, fly ash, Bilecik marble powder and calcareous aggregate crushing powder is used as fine powder source in SCC mix designs. Fresh properties of the SCC mixtures are evaluated by performing fresh unit weight, slump flow, V-funnel, and L-box tests. The hardened properties of the prepared SCC are evaluated with the unit weight, ultrasound pulse velocity and compressive strength tests on the 150x150x150 mm cubic specimens at the end of the 3, 7 and 28 days of curing periods. The experimental work showed that ground granulated blast furnace slag and fly ash are more effective on the consistency of the fresh SCC properties. Especially the passing ability of the SCC is improved by using fly ash as a powder in the mix design. The compressive strength of the SCC is developed by using ground granulated blast furnace slag in the mixture. The marble dust is also effective and beneficial for the cohesion and cost of the SCC.

Strength of Self-Compacting Concrete Containing Metakaolin and Nylon Fiber

In Malaysia, issue to attain durable concrete structures has risen due to shortage of skilled labours. Besides pollution due to construction activities, safety and health of the workers is also a major concern. Self-compacting concrete is able to overcome the problems through its execution. Moreover, properties of SCC can be further improved via incorporation with other materials. Thus, this study was conducted to investigate the strengths and water absorption of SCC containing metakaolin (MK) and nylon fiber (NF) besides determining the effects of MK and NF in SCC. Four mixes (100%C, 95%C 5%MK, 100%C 0.5%NF, 95%C 5%MK 0.5%NF) were being carried out with w/c ratio 0.4 and 1.5% super-plasticizer (SP). Fresh concrete were tested with slump flow, T500 and segregation resistance test whereas hardened concrete were tested with compressive, tensile and flexural strength test. The results of fresh SCC were consistent as all mixes mostly falls in the same class for each respective test. Based on compressive strength test, all mix proportions were able to reach at least 80% of targeted strength, 50MPa. SCC (95%C 5%MK) had the highest compressive, split tensile and flexural strength. While SCC (95%C 5%MK0.5 %NF had better testing results compare to 100%C 0.5%NF.

Fresh State and Mechanical Properties of SCC-POFA-CF Mixture

This paper presents the fresh state and mechanical properties of self-compacting concrete (SCC) with addition of coir fiber (CF) as filler in range of 0.2% to 0.6% and replacing the cement in 10% with palm oil fuel ash (POFA). The workability test such as slump flow and J-ring test were used on the fresh SCC-POFA-CF mixture. The mechanical properties of SCC- POFA-CF in form of compressive, tensile and flexural strength were determine using the compressive test on cube, split tensile test on cylinder and four-point bending test on prism respectively. The increasing amount of CF in mixture resulting the decreasing of workability of SCC-POFA-CF. The SCC mixture with 0.2% CF was selected as optimum as the strength reached the allowable limit of strength. The less crack was occurred on SCC-POFA-CF compared to the control specimen. Therefore, the propagation of crack in prism of SCC was control by coir fiber.

슬럼프 플로 시험을 이용한 고유동 콘크리트의 항복응력과 소성점도 평가

고유동 콘크리트의 레올로지 거동은 빙햄모델로 가정하여, 항복응력과 소성점도로 표현할 수 있다. 항복응력과 소성점도는 회전식 레오미터를 사용하여 측정하는데, 약 20 L 이상의 콘크리트 샘플이 필요하고 복잡한 측정 방법 및 분석 알고리즘으로 인해 현장에서의 사용이 매우 제한적이다. 이 논문에서는 현장에서 콘크리트 품질관리를 위해 필수적으로 적용하고 있는 슬럼프 플로 시험의 결과를 이용하여, 항복응력과 소성점도를 산정하는 모델을 제안하였다. 다양한 배합에 대한 콘크리트 레오미터를 사용한 측정값과 제안된 모델의 산정값을 비교분석하여, 모델의 신뢰성을 검증하였다. 이를 통해, 제안된 모델이 슬럼프 플로의 증가에 따른 항복응력의 감소, T50(지름 500 ㎜에 도달하는 시간)의 증가에 따른 소성점도의 증가하는 일반적인 경향을 적절히 표현함을 확인하였다.

Mechanical properties of self-compacting concrete incorporated with high volume fly ash

Self-compacting concrete (SCC) is beneficial in concrete casting process as it does not need any tools for consolidation process. In addition, the utilization of High content fly ash in has proven in improving mechanical properties of concrete although the slow strength development is an issue to coop with. This paper presented an experimental program on the mechanical properties test of high strength self-compacting concrete incorporated with high content fly ash. The mix proportion for the concrete was prepared based on ACI high strength concrete with the design strength of 45 MPa. The mechanical properties test consists of slump flow test, compressive strength test development, flexural strength test and water absorption test of concrete. The slump flow test was tested for fresh concrete and the strength development test was tested at the age of 14, 28 and 56 days. In addition, test for flexural strength specimen and absorption specimens were tested at the curing age of 56 days. Moreover, the high strength normal concrete specimen was prepared as control mix design. The result shows, less water was need to reach design flowability for Self-Compacting Concrete High content fly ash concrete and it gives impact to lower water absorption for the type of concrete. In addition, at the curing age of 56 days the compressive strength of high strength high content fly ash-self compacting concrete was comparable to the normal concrete.

Development of a 3D Printer for Concrete Structures: Laboratory Testing of Cementitious Materials

This study deals with (a) the development of a prototype 3D printer for concrete structures having a bed size of 1 × 1 × 1 m for a laboratory testing and (b) laboratory testing of cementitious materials with different design mixes to find their suitability and efficacy for the developed 3D printer. In this printer, a program with the concept of computer numerical controlled milling was adopted to control the nozzle motion using an easy graphic user interface program. The experiment was carried out to test mechanical control and proper material properties of the printer. Thus, the optimum values of water-cement ratio of cementitious materials for the 3D concrete printer were determined by experimental trials. Also, the adequate viscosity of the material for layering and dispensing is determined by a slump-flow test. The suitable size of sands for the dispensing system was found through the trials. However, shrinkage cracks occurred during the hardening process for the paste and mortar that polyvinyl alcohol fibers are added to prevent the cracking and build an improved quality 3D printed structure. After suitable and efficient mix ratio is found, compressive strength is measured for the mechanical property. The experiments demonstrated possibility of printing concrete structure using the 3D printer.

Research on shotcrete in mine using non-activated waste coal gangue aggregate

Concrete is a building material that has been widely used in many industries, including coal mines. Because of environmental influences related to traditional aggregates in the concrete industry, a more eco-friendly method of making concrete is needed. Gangue is waste rock produced by coal mine excavation that has led to many environmental and social problems. An eco-friendly way to make concrete is proposed in this paper that replaces traditional aggregates with crushed non-activated coal gangue (NACG). This concrete offers a sustainable alternative to mitigating the environmental problems related to the extraction and depletion of concrete raw materials and the disposal of coal gangue. This experimental research is conducted to study the slump, setting time, air content, compressive strength and splitting tensile strength of different mixture proportions of coal gangue concrete (CGC). The slump, setting time and air content were measured according to the regulations provided by the China National Standard (MOHURD, 2016) using the slump flow test. Hardened properties include compressive and splitting tensile strengths. Optimal mixes design of NACG aggregates were conducted to optimize the fresh and hardened properties of coal gangue concrete. As the percentage of fine NACG aggregates replacement increased, the workability and tensile strength of the coal gangue concrete decreased. Additionally, as the maximum size of coarse NACG aggregates increased, an increase was observed in the compressive strength of coal gangue concrete.

Effects of nano-TiO2, nano-Al2O3, and nano-Fe2O3 on rheology, mechanical and durability properties of self-consolidating concrete (SCC): An experimental study

The objective of this study is to assess and compare the effects of different nanoparticles, namely nano-TiO2, nano-Al2O3 and nano-Fe2O3, on the performance of self-consolidating concrete (SCC) in terms of fresh, mechanical, and durability properties through performing different experiments. TiO2, Al2O3, and Fe2O3 nanoparticles with the average diameter of 18, 15, and 14 nm were used with two different contents of 3% and 5% by weight of cement. For assessing the fresh properties of SCC, slump flow, V-funnel, L-box, and column segregation tests were conducted. For the mechanical properties, compressive strength of concrete was investigated, and for the durability properties rapid chloride migration (RCM), electrical resistivity, rapid chloride penetration (RCP), and water penetration depth tests were carried out. The result showed that the workability properties of the mixes slightly improved by 3% addition of nanoparticles while increasing this value to 5% decreased the workability. For higher content of nanoparticles, the incorporation of nanoparticles in the mixes increased the water demand and consequently caused a reduction of workability.For compressive strength, nano-Fe2O3 showed a superior effect on the enhancement of strength in comparison to nano-Al2O3 and nano-TiO2. This observation was attributed to the formation of calcium ferric hydrate (C-F-H) gel in the microstructure. Moreover, the addition of all the nanoparticles resulted in an improvement of durability properties. High surface area of nanoparticles provided nucleation sites for cement particles and expedited the hydration process development. The formation of a higher content of hydration products helped the densification of microstructure. Moreover, nanoparticles controled the growth pattern of C-S-H gel, which led to the formation of a homogenous microstructure with smaller pore sizes and consequently to lower permeability against penetration of aggressive ions i.e., chloride. It is concluded that partial replacement of cement with nanoparticles on average improved the compressive strength and durability properties of SCC, but resulted in a reduction of workability.

Rheological Properties and Strength of Polypropylene Fiber-Reinforced Self-compacting Lightweight Concrete Produced with Ground Limestone

In this study, self-compacting lightweight concrete (SCLC) was prepared using crushed limestone dust, and the effects of different types of polypropylene fibers and chemical admixtures on the rheological properties of SCLC were investigated. The workability of SCLC was assessed by conducting slump flow, J-Ring, and V-funnel tests, and the compressive strength of the cubic specimens was measured at the ages of 2, 7, and 28 days. Overall, specimens containing fibers displayed lower workability than the control mix; however, a simple adjustment of the dosages of the superplasticizer and viscosity-modifying admixture remedied this problem. The results reveal that the maximum fiber content is 4 kg/m3 for microfibers and 6 kg/m3 for macrofibers. Producing SCLC containing 33% limestone powder by weight as cementitious material satisfied self-compacting concrete requirements and exhibited compressive strength greater than 55 MPa at the age of 28 days.

Effect of silica fume on the compressive strength and modulus elasticity of self-compacting high strength concrete

Self-compacting high strength concrete is one of the concrete that is needed in a green construction of building. In order to improve the workability of self compacting high strength concrete with silica fume which can be applied on the green construction building is needed. This study is aimed to get the optimum percentage substitution of silica fume by 0%, 5%, 10%, 15%, and 20% of cement on the self-compacting high strength concrete. The workability of the concrete will be tested using slump flow test and L-shaped box test then compared to EFNARC requirement for self-compacting concrete. The results show that the slump flow test and L-shaped box test of the concrete comply with the EFBARC requirement. The compressive strength of the concrete tested at 28 days with substitution of silica fume of 0%; 5%; 10%; 15%; and 20% were 34.33 MPa, 36.78 MPa, 50.98 MPa, 52.82 MPa, and 36.78 MPa, respectively. While the modulus elasticity of the concrete tested at 28 days with substitution of silica fume of 0%, 5%, 10%, 15%, and 20% were 21883 MPa, 22410 MPa, 22590 MPa, 22680 MPa, and 21874 MPa, respectively. So the optimum substitution of silica fume in self-compacting high strength concrete using local quartz sand and quartz powder is 10% up to 15%.

Manufacturing of cast in situ ultra high performance fibre reinforced concrete (uhpfrc) - Workability, Tensile and Compressive Strength

The aim of this article is to share on the manufacturing process of Ultra High Performance Fibre Reinforced Concrete (UHPFRC) without heat curing or steam curing, hence, it makes UHPFRC possible to be used for in situ application. The common materials used in numerous previous studies were used in this work to produce UHPFRC: Cement type CEM I, fine sand, silica fume, water and third generation high range water reducer. Three tests were conducted, i.e. Compression test and slump flow test and tensile test. The targeted slump flow is in the range of 600 mm to 750 mm, minimum targeted compressive strength and tensile strength test is 115 MPa and 10 MPa, respectively. In addition, the UHPFRC must exhibit strain hardening properties. As a result, this study proposes the mix proportion of the above mentioned material used to produce UHPFRC which is suitable to be utilized for in situ application.

Effects of steel fibers on flexural strength and impact resistance for self-consolidating concrete plates

Self-Consolidating Concrete (SCC) can be considered as a major innovative satiric expansion in the future of concrete materials and technology during the recent three decades. It has evolved to make adequate compaction with easy concrete placement in constructions, which have overcrowded the restricted zones and reinforcement. This research aims to experimentally study the effect of steel fibers volumetric ratio (Vf ) and effect of chicken wire in enhancement of the behavior of the normal strength SCC. Two types of SCC concrete mixes were prepared and cast for this purpose. One of them was normal strength SSC to serve as a reference mix, while 0.75 % of steel fibers was used in the second one. Slump-flow test, L-box, J-ring and V-funnel tests had been done to investigate the properties of fresh SCC. Compressive strength of the reference SCC was about (33.5MPa) and for 0.75% steel fibers SCC was about (39.7MPa). In addition to that, six identical plate’s specimens of (400×400×20) mm were cast and tested to study the effect of steel fibers and chicken wire on the impact load resistance and flexural load of SCC. Results show that the impact load resistance for steel fibers SCC concrete had been increased by about 60% compared with the reference normal strength SCC mix, while an increase in impact load resistance for SCC of about 50% was gained by using chicken wire mesh. It was noted that the use of 0.75% steel fibers-SCC and chicken wire-SCC plates show an increase in impact resistance and flexural strength by about 20% and 2% compared to the reference normal strength SCC, respectively. The results also indicate that using steel fibers is useful in holding up the formation of transverse cracks and providing affirmative restraint to the successive growth of cracks of plate’s specimens.

EFFECTS OF MINERAL AND CHEMICAL ADMIXTURES ON THE RHEOLOGICAL PROPERTIES OF SELF COMPACTING CONCRETE

One of the most significant innovations on the workability of concrete that was achieved in recent years is self-compacting concrete (SCC). This desirable performance can be attained through the addition of admixtures to enhance its properties. In this study, superplasticizers were blended with fly ash and air entraining admixtures and were tested for Slump Flow, V-Funnel, L-Box, U-Box, and Screen Stability tests based on the European Federation of National Associations Representing for Concrete (EFNARC)specifications and guidelines for SSC. Based on the results of the study, Fly ash with spherical smooth texture enhances the lubrication between the concrete particles while the air-entrainer provides microscopic bubbles acting as ball bearings between aggregates. The best result was obtained in the specimens containing 5.0% superplasticizers due to its dispersibility effect and reduced flow resistance. In general, the air entraining agent blended with 3.7% superplasticizer exhibited the best performance in all workability test conducted.

New methodology to evaluate the Reynolds dilatancy of self-consolidating concrete using 3D image analysis - Coupled effect of characteristics of fine mortar and granular skeleton

The shear-induced volumetric change of 30 self-consolidating concrete (SCC) mixtures with normal and low binder contents was investigated using a coaxial-cylinders tribometer. A new methodology to evaluate the Reynolds dilatancy of SCC using 3D image analyses was proposed. This consisted in assessing the changes in elevation of the free surface of concrete before and after shearing. The flowability and passing ability of the investigated SCC mixtures were evaluated by slump flow, V-Funnel, L-Box, and J-Ring test set-ups. SCC mixtures were considered as a diphasic suspension of a visco-elastoplastic fine mortar (<1.25 mm) and coarser portion of granular skeleton (>1.25 mm).The Reynolds dilatancy measurements were found to be in good agreement with workability of SCC. The coupled effect of the shear rate, relative coarse solid packing fraction of aggregate, and visco-elastoplastic properties of fine mortar on Reynolds dilatancy values were evaluated. Furthermore, the thickness of the lubrication layer in tribology tests was estimated using the results of the proposed Reynolds dilatancy methodology.

Effects of sand/aggregate ratio on strength, durability, and microstructure of self-compacting concrete

In this study, it evaluated the effects of sand/aggregate (S/A) ratio on the flowability, strength, durability, and microstructures of self-compacting concrete (SCC). Testing was performed on specimens using five S/A ratios: 51%, 52%, 53%, 54%, and 55%. Slump flow tests, slump tests, and box tests were used to characterize the rheological properties of the concrete as well as the mechanical properties, including compressive strength, splitting strength, slant shear strength and ultrasonic pulse velocity. Durability was evaluated using tests of absorption, resistivity and initial surface absorption. Microstructures were examined using mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM). The test results indicate that a higher S/A ratio improved flowability. A greater proportion of coarse aggregate (i.e., a decrease in S/A ratio) improved the mechanical properties by 10% compared to the control specimens (S/A ratio: 52%) at 56 days. A higher S/A ratio was shown to improve bonding capacity by enhancing the roughness of the particles and thereby increasing adhesion strength. A higher S/A ratio was also shown to improve the durability of the specimens by permitting denser packing; however, a higher S/A ratio resulted in a thinner interfacial transition zone. MIP analysis did not reveal a correlation between S/A ratio and the interfacial transition zone, whereas SEM photos indicated that a lower S/A ratio reduces the size of the interfacial transition zone.