Influence of bacteria on the compressive strength, water absorption and rapid chloride permeability of concrete incorporating silica fume

The present study aimed at assessing mechanical and durability characteristics of ground granulated blast furnace slag (GGBS)-based geopolymer composites at 5%, 10%, 15%, 20%, 25%, and 30% replacement proportion of silica fume at 12 molarity of NaOH. Mechanical properties were assessed using compression and tension tests, whereas durability characteristics were evaluated using ultrasonic pulse velocity test (UPV), acid test, and rapid chloride permeability test (RCPT), and water absorption (WA) test. Additionally, reduction in mass and strength were also determined due to the acid action on the developed composites. A correlation of compressive strength was also established with the splitting tensile strength, UPV, RCPT, and WA. The presence of silica fume and high NaOH concentration in GPC tends to improve the mechanical strength up toa certain level. UPV values obtained were falling in the range of medium to good category. Chloride ion penetration and water absorption values were reduced by around 23% and 26%, respectively, at 10% silica fume replacement. Mass loss and strength loss were reduced as the % of silica fume increased. A good correlation of compressive strength was obtained with tensile strength, UPV, and RCPT with a coefficient of determination of 0.9681, 0.9665, and 0.9208, respectively. Poor correlation was obtained between compressive strength and water absorption.

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Alkali-activated concretes based on fly ash and blast furnace slag: Compressive strength, water absorption and chloride permeability

Ingeniería e Investigación ◽

10.15446/ing.investig.v40n2.83893 ◽

2020 ◽

Vol 40 (2) ◽

Author(s):

Daniela Eugenia Angulo-Ramírez ◽

William Gustavo Valencia-Saavedra ◽

Ruby Mejía de Gutiérrez

Keyword(s):

Compressive Strength ◽

Blast Furnace ◽

Fly Ash ◽

Water Absorption ◽

Blast Furnace Slag ◽

Construction Materials ◽

Chloride Ion ◽

Chloride Permeability ◽

Alkaline Activator ◽

Furnace Slag

Concretes based on alkaliactivated binders have attracted considerable attention as new alternative construction materials, which can substitute Portland Cement (OPC) in several applications. These binders are obtained through the chemical reaction between an alkaline activator and reactive aluminosilicate materials, also named precursors. Commonly used precursors are fly ash (FA), blast furnace slag (GBFS), and metakaolin. The present study evaluated properties such as compressive strength, rate of water absorption (sorptivity), and chloride permeability in two types of alkaliactivated concretes (AAC): FA/GBFS 80/20 and GBFS/OPC 80/20. OPC and GBFS/OPC* concretes without alkaliactivation were used as reference materials. The highest compressive strength was observed in the FA/GBFS concrete, which reported 26,1% greater strength compared to OPC concrete after 28 days of curing. The compressive strength of alkaliactivated FA/GBFS 80/20 and GBFS/OPC 80/20 was 61 MPa and 42 MPa at 360 days of curing, respectively. These AAC showed low permeability to the chloride ion and a reduced water absorption. It is concluded that these materials have suitable properties for various applications in the construction sector.

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Compressive Strength and Water Absorption of Mortar Incorporating Silica Fume

International Journal of Civil Engineering ◽

10.14445/23488352/ijce-v6i8p106 ◽

2019 ◽

Vol 6 (8) ◽

pp. 39-43

Author(s):

Chai Teck Jung ◽

Tan Cher Siang ◽

Tang Hing Kwong ◽

KohHeng Boon

Keyword(s):

Compressive Strength ◽

Water Absorption ◽

Silica Fume

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Effect of Silica Fume as a Component of Alternative Binder on the Selected Technically Important Characteristics of Bio-Aggregate-Based Composites

Materials ◽

10.3390/ma11112153 ◽

2018 ◽

Vol 11 (11) ◽

pp. 2153 ◽

Cited By ~ 2

Author(s):

Nadezda Stevulova ◽

Jozef Junak ◽

Vojtech Vaclavik

Keyword(s):

Thermal Conductivity ◽

Compressive Strength ◽

Water Absorption ◽

Bulk Density ◽

Silica Fume ◽

River Sand ◽

Biomass Waste ◽

The Matrix ◽

Composite Samples ◽

Hemp Hurd

This experimental study was focused on the application of an alternative binder based on MgO, and the variation of its components by the combination of two MgO products obtained by the calcinations of natural magnesite, siliceous materials (river sand and silica fume), and alkaline admixture in the mixture for a preparation of composite based on biomass waste such as hemp hurds as organic filler. This paper presents the results of the effect of an MgO binder composition on the compressive strength of the bio-aggregate-based composites. Other physical properties, such as the bulk density, thermal conductivity coefficient, and water absorption, were also investigated. The measured strength parameters of the bio-composite samples that were hardened for 28 days demonstrate that the binder consisting of optimal calcined MgO and silica fume as a total replacement for sand ensures a good binding of the matrix with hemp hurd compared to other varied compositions of alternative binder. No significant differences in bulk density and thermal conductivity values were found for these composites. However, the bio-composite specimen with an MgO–SiO2 matrix had the highest compressive strength and achieved the lowest value of water absorption. An increase in hardening time of up to 90 days led to a significant improvement of strength as well as reduction in permeability.

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Effects of Modified Metakaolin Using Nano-Silica on the Mechanical Properties and Durability of Concrete

Materials ◽

10.3390/ma12142291 ◽

2019 ◽

Vol 12 (14) ◽

pp. 2291 ◽

Cited By ~ 12

Author(s):

Nasir Shafiq ◽

Rabinder Kumar ◽

Muhammad Zahid ◽

Rana Faisal Tufail

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Statistical Analysis ◽

Second Phase ◽

Nano Silica ◽

Chloride Permeability ◽

Maximum Compressive Strength ◽

Rapid Chloride Permeability ◽

Anova Technique ◽

Durability Of Concrete

This paper discussed the effects of modified metakaolin (MK) with nano-silica (NS) on the mechanical properties and durability of concrete. In the first phase, trial mixes of concrete were prepared for achieving the desired value of the 28 days compressive strength, and the charge passed in rapid chloride permeability test (RCPT). In the second phase, statistical analysis was performed on the experimental results using the response surface method (RSM). The RSM was applied for optimizing the mix proportions for the required performance by exploiting the relationship between the mix characteristics and the corresponding test results. A blend of 10% MK + 1% NS as part of cement replacement exhibited the highest mechanical properties and durability characteristics of concrete; concrete mix showed that the 28-days compressive strength (CS) was 103 MPa, which was 15% greater than the CS of the control mix without MK or NS. The same mix showed more than 40% higher flexural and split-tensile strength than the control mix; also it resulted in a reduction of 73% in the rapid chloride permeability value. ANOVA technique was used for optimizing the nano-silica and metakaolin content for achieving maximum compressive strength and minimum RCPT value. Statistical analysis using ANOVA technique showed that the maximum compressive strength and lowest RCPT value could be achieved with a blend of 10% MK and 1.55% NS.

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Compressive strength, water absorption, water sorptivity and surface radon exhalation rate of silica fume and fly ash based mortar

Journal of Building Engineering ◽

10.1016/j.jobe.2019.01.011 ◽

2019 ◽

Vol 23 ◽

pp. 369-376 ◽

Cited By ~ 17

Author(s):

Daniel Hatungimana ◽

Caner Taşköprü ◽

Mutlu İçhedef ◽

Müslim Murat Saç ◽

Şemsi Yazıcı

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Water Absorption ◽

Silica Fume ◽

Radon Exhalation Rate ◽

Exhalation Rate ◽

Radon Exhalation ◽

Water Sorptivity

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The Effect of Pozzolanics on the Recycled Aggregates by Surface Treatment

Materials Science Forum ◽

10.4028/www.scientific.net/msf.486-487.305 ◽

2005 ◽

Vol 486-487 ◽

pp. 305-308 ◽

Cited By ~ 3

Author(s):

Jae Jun Kim ◽

Sang Heum Youn ◽

M.J. Cho ◽

H.T. Shin ◽

Jeong Bae Yoon ◽

...

Keyword(s):

Mechanical Properties ◽

Compressive Strength ◽

Surface Treatment ◽

Water Absorption ◽

Silica Fume ◽

Recycled Aggregates ◽

Cement Mortars ◽

Pozzolanic Materials ◽

Adsorption Treatment

To improve the mechanical properties of concretes containing recycled aggregates, pozzolanic materials such as Silica Fume and Meta Kaolin were used to decrease the porosity of the recycled aggregates. These pozzolanic aterials were adhered on the surface of recycled aggregates and closed the open pores so that the water absorption was decreased 1~2% as the amount of adsorption was increased. Compressive strength of cement mortars and concretes using surface treated recycled aggregates reached above 95% of the strength of its natural counterparts. Investigation of the microstructures using the scanning lectron micrographs showed the formation of dense interface after the adsorption treatment of pozzolanics to recycled aggregates.

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