Effect Of Microsilica Research Articles

Analysis of the synergistic effects of micro silica on the mechanical and durability properties of geopolymer concrete incorporating phosphogypsum

Geopolymers are developed by activating aluminosilicates with alkali solutions, stand as inorganic cementitious materials. Their distinct advantages over Portland cement render them highly attractive in the pursuit of carbon neutrality. Moreover, the manufacturing of geopolymers results in notably lower CO2 emissions when contrasted with conventional cement production methods. The industrial byproducts fly ash (FA), phosphogypsum (PG) and micro silica (MS) contained the alumna and silica which can be used for the development of the geopolymer concrete (GPC). This study presents the various proportions of PG content, ranging from 8 % to 40 %, were utilized as a partial substitute for FA, along with MS proportions ranging from 2 % to 10 %, in the preparation of GPC. The alkaline solution was standardized at 12 M of NaOH, and the alkali-to-binder ratio was set at 0.45. The compressive strength, RCPT, sorptivity, water absorption and porosity tests have been conducted for the GPC. The maximum compressive strength of the GPC was 61.53 MPa obtained for FPM8. The compressive strength of the GPC rose with the increasing percentage of MS, peaking at 8 %. The porosity, sorptivity and water absorption were also resulted minimum for the mix FPM8. The scanning electron microscope (SEM) images show the presence of calcium alumino silicate hydrate (C-A-S-H) gel in the specimens, resulting in enhanced mechanical properties and heightened strength of the blended cement paste. The environment impact assessment analysis of the GPC also show that the developed specimens emit less carbon in comparison to the conventional concrete. Hence, the developed GPC from the FA, PG and MS can be used in the application of the sustainable construction work.

Synthesis а compositе containing sialon based on aluminum ferrosilicon and nanosized microsilica in the filtration combustion

A composite containing sialon (β-sialon) and nitride phases (β-Si3N4, Si2N2O) was prepared by self-propagating hightemperature synthesis from a powder mixture of aluminum ferrosilicon and microsilica. The effect of microsilica on the nitriding of aluminum ferrosilicon, the phase composition of nitrided products, and the combustion temperature was studied. The composition of the powder mixture necessary for the efficient synthesis of the sialon phase in the combustion mode has been determined. Ill. 5. Ref. 32.

Effects of micro silica on the compressive strength and absorption characteristics of olive biomass ash-based geopolymer

The use of alkali-activated biomass ash binders is one of the strategies being adopted to produce environmentally friendly concrete. The work presented in this paper is a comparative investigation of the compressive strength and sorptivity performance of olive biomass ash (OBA)-based alkali-activated binders. Micro silica was incorporated into the OBA/kaolin-based binder at replacement levels of 0, 5, 10, 15, and 20 wt %. Mortar specimens were prepared and cured at ambient and an elevated temperature of 60 °C for 24 h. Test results showed that the incorporation of micro silica at a 10 % replacement level led to an increase in compressive strength by 25 % for specimens cured at ambient temperature. However, the addition of 20 % micro silica lowered the compressive strength of the specimens cured at 60 °C by more than 35 %. It was also found that curing geopolymer specimens at elevated temperatures increased the sorptivity by more than 100 % compared to specimens cured at ambient temperature. The incorporation of 10 wt % micro-silica was found to further reduce the sorptivity by 25 % for ambient temperature-cured specimens. X-ray diffraction tests and scanning electron microscopy (SEM) observations were conducted on paste samples to understand the microstructural changes before and after the incorporation of micro silica.

Optimization of the synergistic effect of micro silica and fly ash on the behavior of concrete using response surface method

Abstract The impacts of different replacement levels of micro silica (MS), fly ash (FA), and the combined usage of MS and FA on the behavior of concrete were investigated. Design of experts has been used incorporating the response surface methodology to find the synergetic effect of FA and MS on fresh and hardened concrete properties. A total of 15 and 30% of the binder content were replaced by FA. As well as a total of 5 and 10% of the binder content were replaced by MS. Experimental results of concrete mixtures have been used to construct ANOVA models. These models have also been confirmed to expect the properties of concrete mixtures based on different fractions of FA ash and MS. All statistical models are significant because P-value is less than 5%, and the difference between predicted R 2 and adjusted R 2 is lower than 20%. The variation between confirmation tests for the optimized mixture and test results are lower than 5%.

Effect of Micro-Silica on Fresh and Hardened Properties of Self-Compacting Concrete Reinforced with Glass and Polyvinyl Alcohol Fibres

Self-compacting concrete (SCC) being an innovative and environmentally friendly concrete is impressively accepted in various regions of the world. SCC is a high-performance concrete that can consolidate under its own weight without the aid of mechanical vibration, filling spaces of almost any size and shape without segregation or bleeding. In this study, experimental investigations were carried out to improve the properties of self-compacting concrete by replacing cement with various percentages of Micro silica in SCC having fixed percentages of fly ash, glass, and polyvinyl alcohol fibre. Micro silica content varied from 2% to 10% by weight. Various tests like L-Box, V- funnel, Slump flow, and uniaxial compression tests were carried out on SCC, and the results have been compared with the control mix. It is observed that the hardened properties of the SCC improved with the addition of micro silica. However, the filling ability, passing ability, and resistance to segregation of fresh concrete mix with increasing micro silica content were found to reduce.

Effect of micro-silica on the physical, tensile, and load-deflection characteristics of micro fiber-reinforced high-performance concrete (HPC)

In this research, the influence of micro-silica (MS) was studied on the tensile and flexural behavior of micro-carbon fiber (MCF) reinforced HPC. For this purpose, a total of twelve concrete mixes were designed incorporating six different doses of MCF (at 0%, 0.15%, 0.25%, 0.5%, 0.75% and 1%) with and without MS.The examined properties included compressive strength, splitting tensile strength, load-deflection behavior, ultrasonic pulse velocity, and water absorption. It was found that without MS inclusion, MCF shows a nominal contribution to the mechanical properties. However, the efficiency of MCF incorporation improved phenomenally due to MS addition. The incorporation of MCF at an optimum dose (0.5–0.75% volume fraction) showed 32% and 6% net improvements in modulus of rupture with and without MS, respectively. The micro-filler and pozzolanic effect of MS particles enhanced the bond strength and efficiency of micro-filaments of MCF. MS incorporation delayed the fracture of fiber-reinforced HPC under flexural loading.

Effects of Micro Silica & Flyash on Strength & Durability Parameters of High Strength Concrete

High strength concrete is a term used to describe concrete with special properties not attributed to normal concrete. High-performance means that the concrete has one or more of the following properties: low shrinkage, low permeability, a high modulus of elasticity, or high strength. The application of nanotechnology in concrete has added a new dimension to the efforts to improve properties of High strength concrete. Nano materials, by virtue of their very small particle size can affect the concrete properties by altering the microstructure. Concrete can deteriorate for a variety of reasons, and concrete damage is often as result of combination of factors. This causes stresses in the concrete, which can eventually have resulted in cracking, delamination, and spalling. Concrete resists weathering action, chemical attack, and abrasion while maintaining its desired engineering properties throughout its lifespan. Different concretes require different degrees of durability depending on the exposure of environment and the properties desired. Durable concrete will retain its original form, quality and serviceability when exposed to its environment. The main characteristics influencing the durability of concrete is its permeability to the ingress of water, oxygen, carbon dioxide, chloride, sulphate and other deleterious substances. It became necessary to impart knowledge about durability of concrete and factors affecting durability to the society, as the wide use of concrete as a material in the constructions. This study concerns with the use of Nano silica of size 12 nm in M60 grade of concrete to improve the compressive strength of concrete and study on various durability parameters of High strength concrete. An experimental investigation is planned to carry out with different amount of Fly ash as 15% ,20%, 25%,30% and Micro silica as 5.5%,7%,8.5%,10% in concrete by weight of concrete. have been planned to carry out are workability, compressive test, flexural test, split tensile test. To study durability parameters of High strength concrete with nano silica Rapid chloride penetration test (RCPT), Water Sorptivity test, Acid attack test, Sulphate attack test are conduct. In this study it was observed that t the durability, strength and workability are increase as the percentage of fly ash & micro silica increses

Study on the Erodibility and Mechanical Resistance of Mulches Prepared from Micro Silica–Cement Mixtures

Mulching is fastest strategy to control sand dune movement in arid and semiarid areas. In the present study the effect of micro silica- cement mixture was evaluated as mulch. For this purpose, an experiment was carried out as a factorial arrangement and a completely randomized design with 3 replicates. Three studied factors included 6 micro silica rates (0 as control, 0.5, 2.5, 5, 7.5 and 12.5 percent), 2 rates of mulch thickness (one and two mm layers) and 2 time series (7 and 60 days). Prepared mulches based on different mixtures of micro silica + sand (400 g) and cement were sprayed on sand trays. Then 4 parameters including shear strength, penetration resistance, threshold friction velocity and soil losses at a wind speed of 15 ms−1 were measured on the studied treatments. Results obtained from the analysis of variances revealed that the effect of micro silica rates, thickness of mulch and time on the studied properties were significant. Mean comparisons also showed that shear strength, penetration resistance and threshold friction velocity increased and soil losses of treatments significantly decreased when the micro silica rates increased. The addition of micro silica to sand- cement mixture increased shear strength and penetration resistance by 76% and 82.5% respectively and decreased soil losses by 100%. The erodibility and mechanical properties of the treatments improved by increasing the thickness of the mulch. Moreover, in all studied treatments more improvements occurred in the mentioned properties of mulches during time. The application 7.5% of micro silica after 60 days was the optimal mulch to improve the soil erodibility and to increase the mechanical resistance against wind erosion.

Effect of Micro-silica on the Fresh and Hardened Properties of Self-compacting Concrete Containing Pre-absorbed Superabsorbent Polymer

This research work focuses on the effect of micro-silica (MS) and the performance of pre-soaked superabsorbent polymer (SAP) on the fresh and hardened properties of self-compacting concrete (SCC). In this work, the MS in different proportions of 5, 10 and 15% was used to replace the cement and the pre-absorbed SAP of 0.1, 0.2, 0.3 and 0.4% to the weight of cementitious material was added in concrete as an Internal Curing Agent (ICA). To assess the fresh properties like flowing, filling and passing abilities of SCC, the workability tests such as slump flow, V-funnel and L-box were carried out. Out of several trials, the mix with the addition of 0.3% SAP and replacement of 10% MS gave a positive response in all the examined properties of SCC. The durability tests on permeability properties like water absorption, sorptivity and rapid chloride penetration test (RCPT) of SCC at 28 days and 60 days were conducted. The shrinkage test and Scanning Electron Microscope (SEM) tests were also carried out on all the optimum mixes of SCC at 28 days and 60 days. Better development of calcium silicate gel was observed in the concrete mix that contains both MS and SAP. The results of all the experimental tests exhibit better performance of internally cured concrete containing MS in SCC even at later ages. This study suggests the potential use of pre-absorbed SAP in reducing the manual curing process and utilizing the waste materials effectively in concrete.

Effect of Microsilica on Strength and Microstructure of the GGBS-based Cement composites

Cement production requires substantial energy and significantly accounts for global carbon dioxide emissions. Thus, the consumption of ordinary portland cement (OPC) must be reduced through incorporation of auxiliary materials. Also, the mechanical strength and durability of structures, in the construction industry, need to be improved for economizing the maintenance cost and increasing the service life. This study explores the effect of partial substitution of cement by granulated blast furnace slag (GGBS), and microsilica (MS), the industrial by-products. This study focuses on the use of 10% GGBS and 0-16% MS as a substituent of cement at a water binder ratio of 0.42. The fresh properties were determined to study the effect of these substituents. The compressive strength of all the mixes was determined after 3, 7, 28, and 56 days of treatment. The results were correlated through microstructural analysis. The study revealed that the cement composites with an optimal substituent dosage of 10% GGBS and 12% MS can attain adequate compressive strength and can be used for practical applications.

Experimental investigation of the effect of Micro Silica on roller compacted concrete pavement made of recycled asphalt pavement materials

ABSTRACT In this study, a total of four different mixes were prepared by partially replacing natural aggregates by Recycled Asphalt Pavement (RAP) in different proportions. The results showed that adding RAP to the mixture reduced the mechanical strength of the Roller Compacted Concrete (RCC) mixture. The best mechanical strength was obtained at 50% RAP replacement. To increase the mechanical strength of RCC made with 50% RAP, Micro Silica (MS) with partial replacement of cement at 3%, 6%, 9%, and 12% was used. Increasing the MS content from 3 to 12% caused the mechanical strength of all mixtures to increase. The results showed that RCC7 with 50% RAP and 9% MS had about 20% more compressive strength. Also, the increase in tensile splitting and flexural strength was 6 and 2%, respectively. The statistical analysis indicates that there was a strong relationship (R 2 > 0.98) between flexural strength values estimated from the regression model and the measured laboratory values (this relationship was about 0.84 for compressive strength and tensile splitting strength). The estimation of tensile splitting strength and flexural strength with respect to compressive strength showed that there was a strong (R 2 > 0.98) and good relationship (R 2 > 0.75) between them, respectively.

Effect of micro silica on fiber-reinforced self-compacting composites containing ceramic waste

This paper aims to evaluate the impact of ceramic waste powder (CWP), micro silica (MS) and steel fiber (SF) on self-compacting mortar. CWP at ratios of 10 and 20%, and MS at 1 and 5% by weight of cement were replaced the cement. Beside, SF was added at ratios of 0.5 and 1% of cement. Mini slump flow diameter and mini V-funnel flow time tests were carried out to determine the workability of fresh composites. Compressive strength, flexural strength, water absorption, electrical resistivity and drying shrinkage tests were performed on hardened mortars. Scanning electron microscope (SEM) technique was employed to assess the microstructure. The results indicated that CWP reduced the mechanical properties by about 20% and increased permeability by about 14%. However, inclusion of micro silica particles improved the properties outstandingly. Compressive strength increased about 30% by inclusion of MS. It was also observed that the addition of fibers from 0.5% to 1% increased the flexural strength. This improvement was more obvious in samples with higher contents of micro silica. It can be reported that by including the both micro silica and steel fibers, the bonding between the cement paste and fibers was developed. Replacement of micro silica led to increase of electrical resistivity by about 99% in samples containing 20% ceramic waste powder. The microstructure studies confirmed the significant increase of density and uniformity of the hydration products in the presence of micro silica particles.

Effect of micro silica and ground granulated blast furnace slag on performance of rubberized mortar

Mortar is a cement based paste widely used for constructing masonry structures. It is made by mixing cement and fine aggregate with adequate water cement ratio. Mortar is evenly applied on the wall structures to give a smooth surface finish and it also serves as a joint when applied between bricks. In the present world, Construction industry is facing much difficulty in collecting river sand as there are lot of restrictions imposed by the Government. Recent studies revealed that the waste rubber tire powder can be used instead of river sand. It is also well known fact that the cement manufacture industry causes environmental pollution and so it is better to use alternative eco-friendly material for cement. Micro silica (MS) and ground granulated blast furnace slag (GGBS) are industrial discarded goods and can be utilized as cement alternatives. In this study, Rubberized mortar is prepared by replacing sand with chemically treated rubber tire powder at 5%, 10%, 15% and 20% replacement levels and also replacing cement by MS and GGBS collectively. MS is replaced at 10% and 20% for cement whereas GGBS is replaced constantly at 10% for cement. The study analyses the performance of the rubberized mortar with combined effects of GGBS as well as MS and finally the ideal replacement level of each material is determined. It is found that 10% rubber tire powder for sand, 20% of MS and 10% of GGBS collectively for cement gives better performance than other replacement levels.

Fresh and Hardened Properties of Nano Self-Compacting Concrete with Micro and Nano Silica

Self-compacting concrete (SCC) has undergone a remarkable evolution recently based on the results from several studies that have indicated the chain of benefits SCC provides. Micro and nano materials used as mineral additives in SCC offer several high-performance properties, and this research studies the effects of micro silica (MS) (10%, used as a reference) and colloidal nano-silica (CNS) (2.5%, 5%, 7.5%, and 10%) on the fresh and hardened properties of SCC. All mixtures were estimated using flow, L-box, and V-funnel tests to examine workability and compressive strength, modulus of elasticity and tensile strength as hardened properties. The use of CNS increased the overall compressive strength compared to the reference mixture, with the average increase for 28 days being 41%. The discoveries of this work offer insight into the creation of volitional mineral admixtures for improving the toughness attributes of SCC, increasing enforcement, and offering a more maintainable and practical material.

Evaluation of the effects of nanomaterials on durability of engineered cementitious composites exposed to the aggressive environment

The present study was aimed to evaluate the effect of micro silica, nano silica and carbon nanotube in the engineered cementitious composites made with polyvinyl alcohol fibers. Accordingly, the compressive strength and the modulus of the samples rupture were studied to evaluate the impact of micro silica, nano silica and carbon nanotube in engineered cementitious composite. In addition, different curing conditions were considered to investigate the durability of the mixes. In this regard, the mechanical properties of the samples cured in sulphuric acid and freeze and thaw cycling were compared to those cured in water. The results indicated that the mechanical properties were reduced upon exposure to acid and freeze and thaw cycling. It was also found that the application of micro silica and nano silica made the mixtures compacted and reduced the permeability. The module of rupture was increased significantly by the addition of carbon nanotube. Moreover, the evaluation of the samples cured in the aggressive environment showed that the role of carbon nanotube was significant in increasing the durability of the mixes. Further, the scanning electron microscopy images showed that the crack width was reduced by the addition of carbon nanotube. It was also revealed from the scanning electron microscopy images that the polyvinyl alcohol fibers were completely interacted and connected to the paste.

The influence of micro silica on the compaction properties of cemented sand

In this experimental research, a series of standard Proctor compaction tests have been performed to explore the effect of micro silica on the compaction properties of cemented sand. The cement contents were 3, 5 and 7% and micro silica contents were 0, 0.25, 0.5 and 1% by weight of dry sand. The results showed that micro silica particles increase maximum dry unit weight of sand-cement mixtures and decrease their optimum moisture content. The results of Scanning Electron Microscope (SEM) images confirmed the results of compaction tests and indicated that micro silica can effectively fill the pores of sand-cement mixtures which can lead to creation of a cement-treated sand mixture with compact microstructure.

The Effect of Homogenization Procedure on Mechanical Properties of High-Performance Concrete with Partial Replacement of Cement by Supplementary Cementitious Materials

High-performance concrete is a very specific type of concrete. Its production is sensitive to both the quality of compounds used and the order of addition of particular compounds during the homogenization process. The mechanical properties were observed for four dosing procedures of each of the three tested concrete mixtures. The four dosing procedures were identical for the three mixes. The three mixes varied only in the type of supplementary cementitious material used and in water content. The water content difference was caused by variable k-value of particular additives. The water-to-binder ratio was kept constant for all the concretes. The additives used were metakaolin, fly ash and microsilica. The comparison of particular dosing procedures was carried out on the values of basic mechanical properties of concrete. The paper compares compressive strength and depth of penetration of water under pressure. Besides the comparsion of macro-mechanical properties, the effect of microsilica and fly ash additives on micro-mechanical properties was observed with the use of scanning electron microscopy (SEM) and nanoindentation data analysis. Nanoindentation was used to determine the thickness and strength of interfacial transition zone (ITZ) for different sequence of addition of cement, additive and aggregate. The thickness obtained by nanoindentation was further investigated by SEM EDS line scanning.

Combined effect of micro silica with clay, and gypsum as mulches on shear strength and wind erosion rate of sands

Mulching is known as one of the fastest strategies to control wind erosion and sand dunes movement. We hypothesized that mixed micro silica with clay, gypsum and clay-gypsum as mulches will increase shear strength, threshold friction velocity and decrease soil losses of drifting sands. For this purpose, mixture of micro silica rates (0, 1, 5, 10, 15 and 20%) with clay, gypsum, and clay-gypsum applied on sand surfaces. After 60 days of mulching, shear strength, the threshold friction velocity and soil losses at a wind speed of 15 m/S at the height of 20 cm for 20 min. The results of this research revealed that the addition of 10% of micro silica in combination with clay and clay-gypsum increased the shear strength up to 10.6 and 37.5% and the threshold friction velocity up to 45.2 and 48.5%, respectively and decreased soil losses up to 100% in comparison with the samples without micro silica. Adding micro silica to gypsum had no considerable effect on shear strength, threshold friction velocity and soil losses. It was concluded that no pozzolanic reaction occurred between micro silica and gypsum and it was found that improvement in mechanical property and erodibility of clay-gypsum mulch was probably due to the pozzolanic reaction between micro silica and clay. Application of 10% of micro silica in combination with clay or clay-gypsum is therefore recommended as suitable mulch.

Effect of micro silica and aggregate size on cracking of self-compacting concrete

In the evaluation of long-term serviceability leading to prevention of damage of self-compacting concrete (SCC) structures, a thorough understanding on fracture parameters and cracking performance from initial stage to hardened stage is important. This paper reports the effect of coarse aggregate size and micro silica addition on fracture characteristics and ductility of SCC. Experiments were performed by conducting three-point bending tests on notched beams as per recommendations by Rilem standards. For all mixes, the parameters are analysed by the size-effect method. The tests proved that an increase in the size of the coarse aggregates can increase the fracture energy and ductility due to changing fractal dimensions and the fracture process zone length. A 10% addition of micro silica showed better fracture properties. Equations for assessing the fracture energy and length of the fracture process zone using a statistical approach were then developed.

Coupled effect of coarse aggregate and micro-silica on the relation between strength and elasticity of high performance concrete

This paper examines the relation between strength and elastic modulus of high performance concrete (HPC) tailored from various heavy and normal weight aggregates coupled with the effect of micro-silica as a supplementary cementitious material (SCM). Elastic modulus of concrete is an important mechanical property and plays an important role for the calculation of deformations in the structural components. Experimentation was conducted in precise laboratory environment and all other parameters were kept constant in the mixtures. This investigation was prompted to supply the construction industry with appropriate information on how specific properties of HPC mixtures can be improved using local normal and heavy weight aggregates and incorporating supplementary cementitious materials. In other words, this paper will encourage the local aggregate consumption in mega projects that to be constructed for special purposes. In this investigation, dissimilar types of normal and heavy weight coarse aggregates were used. It was found that it is worthy to study experimentally the relation between strength and MOE of HPC when different types of coarse aggregates are used for an indicated HPC mixture with a corresponding combination of supplementary cementitious material. The comparison of experiment results with the ACI prediction models showed that the models should be enhanced for accurate prediction for the effect of aggregate type with and without the use of micro-silica as supplementary cementitious material. An assessment of the need for an aggregate and micro-silica based modification to the ACI models is also proposed. The experimental work conducted in this investigation confirmed that the type of aggregate and its combination with a supplementary cementitious material would have important influence on the HPC characteristics. Hence, the use of appropriate values for the strength-MOE relation for a HPC mixture based on the nature of used aggregates and SCM is recommended. However, such values might be not available in some cases, if so the experimental trend lines presented in this study can be used to calculate them.