scholarly journals Effect of nano-silica on Portland cement matrix

2019 ◽  
Vol 12 (6) ◽  
pp. 1383-1389 ◽  
Author(s):  
T. M. MENDES ◽  
W. L. REPETTE
Keyword(s):  
Portland Cement ◽  
Size Distribution ◽  
Mechanical Performance ◽  
Current Trend ◽  
Pozzolanic Reaction ◽  
High Specific Surface Area ◽  
Nano Particles ◽  
Cement Matrix ◽  
Nano Silica ◽  
Main Effects

Abstract The use of nano-particles is a current trend that may play an important role for improving the mechanical performance of Portland cement. The aim of this study is to evaluate the effect of nano-silica on Portland cement matrix. The particle size distribution of Portland cement matrix was modified by the incorporation of 11, 6.2, 3.1, 1.7, 0.85 and 0.42 wt.% of nano-silica. The water demand and the consumption of dispersant were adjusted, and the rheological properties of suspensions were analyzed through rotational rheometry. The mechanical performance of studied mixtures was evaluated by the compressive strength. The pore size distribution was measured by mercury intrusion porosimetry (MIP), and the hydration was analyzed through X-ray diffractometry. The rheological behavior presented a considerable changed, as a consequence of high specific surface area of nano-particles. The optimum content of nano-silica, or the smaller quantity of nano-particles, that leads to the maximum strength gain, varied according to the water to solids ratio. An increasing on the hydration and a pore refinement were obtained due to the use of silica nanoparticles. The particle’s packing and the pozzolanic reaction were the two main effects of nano-silica on the microstructure of Portland cement matrix.

scholarly journals Effect of nano-silica on Portland cement matrices containing supplementary cementitious materials

2021 ◽  
Vol 14 (4) ◽  
Author(s):  
Thiago Melanda Mendes ◽  
Wellington Longuini Repette
Keyword(s):  
Portland Cement ◽  
Mechanical Performance ◽  
Mercury Porosimetry ◽  
Cementitious Materials ◽  
Nano Particles ◽  
Supplementary Cementitious Materials ◽  
Nano Silica ◽  
Fixed Amount ◽  
Cement Pastes ◽  
Cement Matrices

abstract: For a controlled granulometry, this study evaluates the effect of nano-silica on mechanical and rheological properties, as well in the microstructure of Portland cement matrices containing a fixed amount of supplementary cementitious materials and three different types of cements. The rheological behavior of cement pastes was evaluated by rotational rheometry and mechanical performance was measured througth the compressive strength. The microstructure was analyzed by intrusion mercury porosimetry and scanning electron microscopy. There was an increasing on the viscosity of the cementitious matrices, as a consequence of the reduction in the inter particle separation of these suspensions. The optimum content of nano-silica varied according to Ca/Si ratio of Portland cement matrices containing supplementary cementitious materials. The use of nano-silica allowed to modify the pore size distribution of cementitious matrices. And the structure of nano-silica in cementitious matrices has occurred in layers or agglomerates of nano-particles covered by hydration products.

Mechanism of Cement Paste with Different Particle Sizes of Bottom Ash as Partial Replacement in Portland Cement

2017 ◽  
Vol 68 (10) ◽  
pp. 2367-2372 ◽  
Author(s):  
Ng Hooi Jun ◽  
Mirabela Georgiana Minciuna ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Tan Soo Jin ◽  
Andrei Victor Sandu ◽  
...  
Keyword(s):  
Portland Cement ◽  
Construction Material ◽  
Bottom Ash ◽  
High Volume ◽  
Cement Composite ◽  
Pozzolanic Reaction ◽  
High Specific Surface Area ◽  
Partial Replacement ◽  
Natural Aggregates ◽  
Pozzolanic Properties

Manufacturing of Portland cement consists of high volume of natural aggregates which depleted rapidly in today construction field. New substitutable material such as bottom ash replace and target for comparable properties with hydraulic or pozzolanic properties as Portland cement. This study investigates the replacement of different sizes of bottom ash into Portland cement by reducing the content of Portland cement and examined the mechanism between bottom ash (BA) and Portland cement. A cement composite developed by 10% replacement with 1, 7, 14, and 28 days of curing and exhibited excellent mechanical strength on day 28 (34.23 MPa) with 63 mm BA. The porous structure of BA results in lower density as the fineness particles size contains high specific surface area and consume high quantity of water. The morphology, mineralogical, and ternary phase analysis showed that pozzolanic reaction of bottom ash does not alter but complements and integrates the cement hydration process which facilitate effectively the potential of bottom ash to act as construction material.

Effect of W/B ratios on pozzolanic reaction of biomass ashes in Portland cement matrix

2012 ◽  
Vol 34 (1) ◽  
pp. 94-100 ◽  
Author(s):  
V. Sata ◽  
J. Tangpagasit ◽  
C. Jaturapitakkul ◽  
P. Chindaprasirt
Keyword(s):  
Portland Cement ◽  
Pozzolanic Reaction ◽  
Cement Matrix ◽  
Biomass Ashes

Silica Modified PP Fiber for Improving Crack-Resistance of Cementitious Composites

2011 ◽  
Vol 332-334 ◽  
pp. 2058-2064 ◽  
Author(s):  
Zhi Qian Yang ◽  
Jian Zhong Liu ◽  
Jia Ping Liu ◽  
Chang Feng Li ◽  
Hua Xin Zhou
Keyword(s):  
Crack Resistance ◽  
Sol Gel ◽  
Polypropylene Fiber ◽  
Chemical Deposition ◽  
Cementitious Materials ◽  
Nano Particles ◽  
Cement Matrix ◽  
Interfacial Property ◽  
Nano Silica ◽  
Fiber Matrix

To improve the interfacial bonding properties of polypropylene fiber-cement matrix, a new type of nano-silica modified polypropylene fibers was prepared by direct blend-spinning. As a comparison, Another polypropylene fiber was modified by surface chemical deposition of the silica particles by sol-gel method. The distribution of nano-particles on the fiber surface was observed with scanning electron microscope (SEM). This paper focuses on the effects on crack-resistance properties of fiber reinforced mortar(FRM) and present the mechanism of improving fiber-matrix interfacial properties, especially. The results demonstrate that the modified fiber with well-distributed of nano-silica has excellent mechanical properties, and crack resistance. The interfacial property of fiber-matrix is improved because of silica’s hydration activity. As the use of two kinds of modified fiber, the cementitious materials crack area is significantly decreased. In conclusion, the modified fiber by chemical deposition method which has slightly better overall performance.

scholarly journals Effects of nano-silica on mechanical performance and microstructure of ultra-high performance concrete

Cerâmica ◽  
2017 ◽  
Vol 63 (367) ◽  
pp. 387-394 ◽  
Author(s):  
T. M. Mendes ◽  
W. L. Repette ◽  
P. J. Reis
Keyword(s):  
High Performance ◽  
Mechanical Performance ◽  
High Performance Concrete ◽  
Raw Materials ◽  
Microstructural Analysis ◽  
Cementitious Materials ◽  
Pozzolanic Reaction ◽  
X Ray Diffraction ◽  
Nano Silica ◽  
X Ray

Abstract The use of nanoparticles in ultra-high strength concretes can result in a positive effect on mechanical performance of these cementitious materials. This study evaluated mixtures containing 10 and 20 wt% of silica fume, for which the optimum nano-silica content was determined, i.e. the quantity of nano-silica that resulted on the higher gain of strength. The physical characterization of raw materials was done in terms of particle size distribution, density and specific surface area. Chemical and mineralogical compositions of materials were obtained through fluorescence and X-ray diffraction. The mechanical performance was evaluated by compressive strength, flexural strength and dynamic elastic modulus measurements. The microstructural analysis of mixtures containing nano-silica was performed by X-ray diffraction, thermogravimetry, mercury intrusion porosimetry and scanning electron microscopy. Obtained results indicate an optimum content of nano-silica of 0.62 wt%, considering compressive and flexural strengths. This performance improvement was directly related to two important microstructural aspects: the packing effect and pozzolanic reaction of nano-silica.

Making Nano-Porous SiO2 Insulation through Filter-Pressing of Foamed Slurry

2012 ◽  
Vol 512-515 ◽  
pp. 319-322
Author(s):  
Xing Shi ◽  
Shi Xi Ouyang ◽  
Yu Feng Chen ◽  
Mao Qiang Li ◽  
Shi Chao Zhang ◽  
...  
Keyword(s):  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Porous Silica ◽  
Nano Particles ◽  
Insulation Material ◽  
Solid Concentration ◽  
Nano Silica ◽  
Hydrophobic Sio2 ◽  
Aqueous Slurry

Nano-porous SiO2 insulation material was made from foamed aqueous slurry of nano-silica powder by filter-pressing. The foamed aqueous slurry mainly consists of hydrophobic SiO2 nano-particles, xonotlite whiskers and glass fiber. The latter two will enhance strength of the insulation material. Rheological properties of the foamed slurry with varying solid mass concentration were studied. The effect of forming pressure on the density and pore size distribution of the nano-porous silica material was investigated. It was found that the foamed slurry with solid concentration less than 17% behaves pseudoplastic as decreasing its apparent viscosity with increasing of shear rate during rheological testing. Homogeneous foamed slurry can be obtained when solid concentration in it is below 7%. Such slurry should be dewatered into solid concentration being of 10-15% before filter-pressing. Rigorously stirring of the concentrated slurry is required before pouring it into a mould, which leads to reducing the viscosity of the slurry and helps uniformly filling mould. During pressing the loading speed should be strictly controlled in order to reaching designed pore size distribution in SiO2 insulation material. The SiO2 insulation material with apparent density about 0.45g/cm3 and pore size mainly ranging from 10 to 50nm was obtained.

Evaluating Micro-Structure, Hydration and Thermal Expansions of Cement Containing Nano-Silica

GIS Business ◽  
2020 ◽  
Vol 15 (1) ◽  
pp. 158-165 ◽  
Author(s):  
Dr. Sarvesh PS Rajput
Keyword(s):  
Portland Cement ◽  
Mechanical Characteristics ◽  
Microstructural Properties ◽  
Nano Silica ◽  
Micro Structure ◽  
Microstructural Characteristics ◽  
Mechanical And Microstructural Properties

This study reported that the addition of nano-silica enhances the mechanical characteristics of concrete as its compressive, flexural and tensile split strengths are increased. As a comparison mixture to equate it along with nano-modified concrete, ordinary samples of Portland cement (OPC) have been utilized. Herein, upto 6.0 percent of OPC has been substituted by nanosilica. In fact, the introduction of nanosilica improves mechanical and microstructural characteristics of concrete by significantly (28 to 35%). The finding therefore, indicated that partly replacing OPC with up to 5 percent nanosilica increases the mechanical and microstructural properties cured up to ninety days as opposed to the standard OPC mix.

Effect of microcrystalline cellulose on geopolymer and Portland cement pastes mechanical performance

2021 ◽  
Vol 288 ◽  
pp. 123053
Author(s):  
Saulo Rocha Ferreira ◽  
Neven Ukrainczyk ◽  
Keoma Defáveri do Carmo e Silva ◽  
Luiz Eduardo Silva ◽  
Eduardo Koenders
Keyword(s):  
Portland Cement ◽  
Microcrystalline Cellulose ◽  
Mechanical Performance ◽  
Cement Pastes

scholarly journals Mechanical Properties of an Igneous Aggregate-Modified Hydraulic Concrete

2001 ◽  
Vol 10 (2) ◽  
pp. 096369350101000
Author(s):  
E. Alonso ◽  
L. Martvnez-Gomez ◽  
W. Martvnez ◽  
L. Villaseρor ◽  
V.M. Castapo
Keyword(s):  
Mechanical Properties ◽  
Portland Cement ◽  
Mechanical Testing ◽  
Mechanical Performance ◽  
Central Mexico ◽  
Natural Sources ◽  
Hydraulic Concrete ◽  
West Central ◽  
Careful Control

Portland cement concretes were prepared by adding different igneous materials from west central Mexico. The results of the mechanical testing of these materials show the feasibility of employing igneous minerals to produce concretes and mortars, provided a careful control of granulometry and the geochemistry involved is attained. The mechanical performance, as well as the workability of the slurries can be managed by the convenient use of commercial additives (i.e. water reducers and aging accelerators). These results open the attractive possibility of expanding the natural sources of concrete-forming elements.

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