Thus, a cationic polyvinyl alcohol (PVA) polymer, modified by glyoxal and boric acid, was discovered due to its excellence in associating with the FLA A additive for controlling the free cement-based material water amount and preventing the chelating effect of FLA A chains on the surface of the cement-based material. Glyoxal/boric acid-modified ...
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boric acid and oxygen concentrations in these systems are low, the pH is controlled at mildly alkaline conditions ... •Boric acid corrosion of containment vessel liners, concrete, and rebar is not within the scope of the guidebook •Guidebook does …
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After some decades in applying boric acid with natural isotopic abundance (natural boric acid, NBA) solution as a neutron absorber, some nuclear facilities have started to use boric acid enriched ...
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In this study, the effects of boric acid addition to pumice aggregate lightweight concrete at different ratios (Ref: 0%, 2%, 4% and 6%) were investigated.
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Boric acid (H 3 BO 3 ) or borax (Na 2 B 4 O 7 ·10H 2 O) [19, 20] can significantly regulate acid-base reactions to improve the strength or workability of an MKPC system [21]; therefore, boric ...
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When reactive magnesia is mixed with a magnesium sulfate solution, rosette-like Mg(OH) 2 is also formed in the system, decreasing the strength of MOS cement [36,37]. Various weak acids and salts, including sodium citrate [35], citric acid (CA) [39], soluble phosphates [29], phosphoric acid [29], boric acid (BA) [40], and tartaric acid [28] have been used as additives to …
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To enhance the early performance of magnesium potassium phosphate cement (MKPC) and compensate for loose of compressive strength caused by the addition of boric …
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Except for the control mixture, boric acid (BA) was used at the ratios of 0.25-1.00% of weight of cement in mortar mixtures with Portland cement. Setting times dependent on pH, EC and T changes of ...
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This research investigated the hydration process and mechanical properties of low-carbon MOS cement containing citric acid and boric acid. A boric acid-citric acid gel precursor is formed in MgSO 4 solution, ... Therefore, the MOS cement slurry with the additives shows a decrease in the initial pH value and Mg 2+ concentration (Fig. 4 a). An ...
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Table 1 shows the chemical compositions of the used MgO powder. Since the initial setting time of MPC paste is very rapid (between 30 and 240 s), boric acid (H 3 BO 3 ) is added to reduce the ...
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In this study, the effect of boric acid addition on the microstructure of gypsum plaster was investigated to determine an environmentally friendly gypsum additive that may enhance mechanical strength, fire resistance, and X-ray radiation attenuation properties. The mechanical strengths of bare gypsum and boric acid-added (0–0.5% by weight with respect to gypsum …
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Discover the impact of substituting boron compounds with glycol-based grinding aids on cement strength. Explore the use of MEG and DEG as grinding aids and borax and boric acid as boron compounds. Uncover the effects on …
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Results of boric acid added mortar samples were compared with control samples produced by using Portland cement, BAB cement and CAC cement. 2, 7, and 28 day compressive/ffexural strength of mortar ...
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OPC cements can be modified by using a range of additives. These may be defined as additives (at a level of ~5%), such as gypsum, which acts to retard hydration; replacements (at high levels up to 90%) such as BFS or PFA in blended or composite cements; or as admixtures (at levels of ~1%) such as superplasticisers. The main cement modifiers (Tables 15.7 and 15.8) include …
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Citric acid and citrates [29,30], boric acid [31,32], ferric sulfate [33], phosphoric acid and phosphates [34] are incorporated to retard the hydration process and improve the mechanical performance of MOS cement. Because these chemical additives can promote the hydration reaction of MOS cement to form 5 Mg(OH)2·MgSO4·7H2O (5 1 7) phases.
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An additive composition for incorporation in settable Portland cement compositions, said additive composition consisting essentially of from about ID to 90 weight percent of a water-soluble amine formate salt formed by the reaction of a substantially nonhydroxyl containing amine containing up to about.20 carbon atoms and formic acid, and about ...
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an additive for producing shaped gypsum articles comprises boric acid and/or salts of boric acid, tartaric acid and/or salts of tartaric acid, and cement. It can be demonstrated that the substances known per se constituted by boric acid, borates, tartaric acid, and tartrates (salts of tartaric acid) have an improved effect with regard to sag resistance when they are combined with cement.
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Belite-rich cement (BC) is an alternative type of cement, which has attracted scientific interest over the last 20 years [5], [6].BC, in contrary to conventional OPC, contains a higher percentage of belite and a lower percentage of alite which are the impure forms of dicalcium silicate (C 2 S) and tricalcium silicate (C 3 S), respectively. The different …
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Acidic additives such as citric acid [22], [23], tartaric acid [24], phosphoric acid [25], [26], and boric acid [27], [28] have been introduced in large quantities to modify MOS composites. The chelation of Mg 2+ with carboxyl groups can promote the 517 phase with high strength, resulting in improved mechanical strength and water resistance of MOS.
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In this study, different percentages of boric acid 1, 2, 3, 4 & 5% were added to the high-performance concrete (HPC) and the effects on hydration process and strength were …
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Thus, a cationic polyvinyl alcohol (PVA) polymer, modified by glyoxal and boric acid, was discovered due to its excellence in associating with the FLA A additive for controlling the free cement ...
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The main product of the reaction is boric acid, and gypsum is collected in the filters as a by-product of the boric acid production process [6][7] [8] [9][10]. Since the gypsum sludge contains ...
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The usage of boron containing wastes obtained from boric acid (H 3 BO 3) production or the enrichment process of tincal (Na 2 B 4 O 7 ·10H 2 O) as supplementary materials in cement composites enhances the properties of the cement composites. The gypsum-like composition and pozzolanic features of borogypsum, which is obtained as a by-product of …
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Currently, various retarders are used in oilwell cementing to manage the safety and flowability of the cementing operation. Conventional retarders often comprise lignosulfonate, tannin, cellulose, saccharide, tartaric acid, organic phosphine, and boric acid (Zhigang et al., 2018).However, with the increasing number of deep and ultradeep wells, most conventional …
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The aim of this work is to study the influence of boron and its compounds, boric acid and borax, on the hydration of Portland cement. The samples – cement paste modified by the addition of boron, borax and boric acid in different …
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The hydration of cement in addition to boric acid in the high-performance concrete has been studied using, X-ray diffraction, Fourier Transfer Infrared Spectrometry (FT-IR) and Field Emission ...
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The additives effects on fresh concrete. As mentioned before, it has been reported that the addition of about 1% by weight of boric acid to concrete is generally considered to be adequate for shielding purpose (Kaplan, 1989). It has been noticed in this work that boric acid has a deleterious effect on the setting of cement even at lower ratios.
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Retarders are cement additives designed to delay the thickening time of cement slurries.Top of Form The thickening time denotes the duration during which the cement slurry can be manipulated following its mixing with water. 10,11 The problem of inadequate thickening ... encompassing boric acid, phosphoric acid, hydrofluoric acid, and chromic ...
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Variation in pH of magnesium phosphate cements containing 15% retardant additive (boric acid) and 60% water.
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Cement Retarders are essential chemical additive for cementing in oil and gas well. Here, we explain its main mechanisms and common chemicals ... Another hydroxycarboxylic acid with a strong retarding effect is citric acid. …
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Boric acid is commonly used as an additive to concrete to increase its workability and setting time, and prolong its hydration (Mollamahmutoglu and Avci 2021). ...
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