The addition of silica fume (silane-treated) to cement paste has been shown to increase the specific heat by 7% and decrease the thermal conductivity by 38% relative to the cement paste without silica fume [1]. Without the surface treatment using silane, the effects of silica fume on both specific heat and thermal conductivity are in the same ...
Improving the workability and strength of silica fume concrete by using silane-treated silica fume . × Close Log In. Log in with Facebook Log in with Google. or. Email. Password. Remember me on this computer. or reset password. Enter the email address you signed up with and we'll email you a reset link. ...
The specific heat of cement paste was increased by 12% and the thermal conductivity was decreased by 40% by using as admixtures silane-treated silica fume and silane-treated carbon fibers. The specific heat was increased by the carbon fiber addition, due to fiber-matrix interface slippage. The increase was in the order: as-received fibers ...
Silane and silica fume together are effective admixtures for increasing significantly both the specific heat and the thermal conductivity of cement paste. Silica fume alone increases the specific heat but decreases the thermal conductivity. Silane provides a network of covalent coupling among the silica fume particles, thereby increasing both ...
Silane as an admix- in air at room temperature and a relative humidity of ture was found in this work to increase the thermal diffu- for 28 days. sivity of cement containing silica fume by up to 27%, The thermal conductivity (in W /m K) was given by the increase the specific heat of cement containing silica fume product of the thermal ...
The physical properties and chemical analyses of cements C1, C2, and silica fume are given in Table 1. Both cements, whose specific area is about 400 m 2 /kg, have an identical content of tricalcium silicate, yet they have a different content of tricalcium aluminate. The C2 cement, which may be used in seawater and in a sulphate water …
In this paper, we report that the silane treatment conducted on carbon fibers improves the mechanical properties of carbon fiber reinforced cement paste beyond the levels attained by using ozone-treated carbon fibers. Silica fume is commonly used along with carbon fibers in order to help the dispersion of the fibers in the cement mix [5].
Due to the addition of silica fume and amino vinil silane, Xu and Chung [7] increased the thermal capacity of cement mortars in 50% and its thermal conductivity in 38%, as well as the compressive ...
Abstract. The surface modification of silica fume was made by using a silane coupling agent. The storage modulus and the loss tangent of different cement mortars …
The specific heat of cement paste was increased by 12% and the thermal conductivity was decreased by 40% by using as admixtures silane-treated silica fume and silane-treated carbon fibers. The specific heat was increased by the carbon fiber addition, due to fiber-matrix interface slippage.
Surface modification of silica fume was made by using a silane coupling agent. The storage modulus and loss tangent of the different cement mortars after adding the silane - treated silica fume or … Expand. 8. Save. Interfacial transition zone in concrete. J. Ollivier J. Maso B. Bourdette.
Due to the large area of the interface between the silica fume and cement matrix, silica fume was able to enhance the damping capacity, i.e. extra energy dissipation caused by interface slippage. The covalent coupling silane introduced by the silane surface modification would move when the paste experienced vibration, thus providing another ...
The effects of silane treatment of the silica fume and of the use of silane as an additional admixture are also addressed. bstract">The effects of silica fume as an admixture in cement-based ...
A silane with a 5000 molar mass PEO segment [PEO(5000)-silane] was also attached to A380-fumed silica using toluene as the grafting solvent; the samples were rinsed with both toluene and methanol. The maximum amount of silane that could be covalently attached to the fumed silica was about 38%. For
This trend applies whether the silica fume is as-received or silane-treated. For any of the formulations, silane-treated silica fume gives substantially higher strength and modulus than as-received silica fume. The highest tensile strength and modulus are exhibited by cement paste with silane-treated silica fume and silane-treated fibers.
Dosage of silica fume could effectively improve the compressive strength of UHPC, while slag had a certain negative impact on its strength. ... The main reason was that the siloxane group in the …
Silica nanoparticles, Aerosil 200, with an average primary particle size of 12 nm were chemically modified by γ-aminopropyltriethoxy silane (APS) via a two-step sol–gel process. Effects of the treatment variables including reaction temperature, water content, and silane concentration on the colloidal stability and the amount of APS grafting on the …
1. Introduction. Silica fume (SF), also known as micro-silica, is a spherical amorphous silica originally being a byproduct in the metallurgy from fume flue, captured by cyclone dust collector [1].SF is regarded as solid waste first, but later found its utilization in cement and concrete industry as ultrafine supplementary cementitious materials (SCM) …
Leung et al. found that the combined use of fly ash and silica fume is much more effective in reducing the water sorptivity and the total water absorption amount than using fly ash alone as the supplementary cementitious material [25]. ... The silane emulsion used in this study is an aqueous anionic emulsion of isooctyl triethoxysilane with ...
The compositions of silica fume are given in Table 1. The silane coupling agent used for treated silica fume was KH550 [ H2N (CH2)3 Si (OC2 H3)3] from Chemical. Agent Corporation in Shanghai of China.
Likewise, surface-treated particles via the modification of silane (i.e. silica fume [37], fly ash [38], nanoparticles (nano-SiO 2, nano-TiO 2, nano-ZnO) [39]) were also determined to attain better workability and mechanical strength for cement matrix [37], lower moisture sensitivity of asphalt concrete [38], and improvement of the ultraviolet ...
This makes the organofunctional silane be used in very wide applications, e.g. as coupling agents in inorganic filler modified polymer composites [3], [4], as steel fiber or polymer fiber modifier in fiber reinforced mortars for improvement of fiber dispersion and enhancement of the interfacial bonding [5], [6], as silica fume coating for ...
Silane-modified polycarboxylate superplasticizer (SC-PCE) Free radical co-polymerization Polycondensation Gel 1. Introduction Silica fume (SF), also known as …
The use of both that attained by using untreated silica fume alone, but still silane (0.2% by weight of cement) and untreated silica above that for plain cement paste. fume (as two admixtures, last column of Table 2) en- The ability of silica fume to enhance the damping hances the tensile strength, compressive strength and capacity is due to ...
Dispersing silica fume in cementitious materials by silane copolymerized polycarboxylate Superplasticizer: On the role of dispersion effectiveness as a function of …
Silica fume, a fine particulate, is an admixture that can be used to improve the degree of fiber dispersion [14], [16] and to improve the bond between fibers and cement matrix [17].Polymers are admixtures that can be used to improve the bond between fiber and cement matrix [16], [17], [18], [19].In this paper, we report that silane (molecular, but …
The surface of silica fume (SF) was modified with silane coupling agent KH-570 under acidic conditions.The optimum process parameters were determined by controlling the modified time and the ...
Other routes use silane or tetraiodosilane (SiI4). ... Silica fume is an efficient active admixture that can significantly improve concrete's strength, impermeability, frost resistance, and durability. The characteristics of silica fume concrete have attracted people's attention, and silica fume concrete is widely used in water conservancy and ...
In this paper, we report that the workability of silica fume mortar is greatly enhanced by using silane-treated silica fume, i.e., silica fume that has been coated …
The surface treatment of silica fume with silane coupling agent prior to incorporation in a cement mortar resulted in composites exhibiting increases in loss tangent by 5%–200% and storage ...
The silanized silica fume showed no effects on the flexural properties but caused considerably increment in the strength and modulus properties of epoxy sample.
Silane can be introduced to silica fume cement in two ways: (i) as a coating on silica fume (i.e., coating the silica fume with silane prior to using the silica fume), and (ii) …
Silane can be introduced to silica fume cement in two ways: (i) as a coating on silica fume (i.e., coating the silica fume with silane prior to using the silica fume), …
Silica fume-Silica loading (10, 20, 30, 40, 50 phr) Curing Characteristic The cure time of all the reinforced composites increased with the increase in silica fume loading Tensile Strength and Modulus Composite added with 20 phr silica showed improved tensile strength. The tensile strength dropped slightly with further increase of silica fume ...