76 Vol.39 S iin et al: Preparation of a-High Strength Gypsum from Flue Gas Desul... 3, and the highest absolute dry compressive strength reached 25.3 MPa. And after 8 cycles of mother liquor recycling, high-strength α-CSH crystals could still be prepared[12]. Jia et al reported that trace NaCl and Na
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The EMC of a building material thus spans from an absolute dry state of zero moisture content to its vacuum saturation moisture content, as the partial pressure of water vapor varies from zero to full saturation value for a given temperature. But the path that connects these two extremes is often not unique. This is due to a phenomenon called
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crystals [3]; hence β-H requires more water than the α-H does in order to obtain a paste of standard consistency because it has much higher specific surface area.
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Phosphorus building gypsum [6, 7] is the dried product obtained after ... The compressive strength and flexural strength of the phosphogypsum specimens can be determined following the standard Gypsum plasters - Determination of mechanical properties (GB/T 17 669.3–1999). ... the PBG's dry flexural strength and dry compressive strength show a ...
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As can be seen from Figure 1, under different mass ratios of material to ball and milling speed, the absolute dry flexural strength of phosphorus building gypsum first increased and then decreased ...
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unconfined compressive strength test results were found in the gypsum content of 0% and curing for 0 days of 3.8667 kg / cm2. While, the largest found in the gypsum content of 8% with 28 days of 14.2 kg / cm2. Curing increases the strength of soil. The addition of gypsum is effective for stabilization of clay soil. Keywords
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The fired gypsum is used as a dry, powdered product, for example, as a binder in plaster or screed. Before processing, these dry products are mixed again with water. Gypsum, plaster and gypsum screed, and gypsum plasterboard consist essentially of …
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When the content was 1%, the strengthening effect reached the optimum, with the absolute dry flexural strength and absolute dry compressive strength being increased to 8.1 MPa and 20.5 MPa, respectively, which were 50% and 24% higher than those of the blank group; when the content was 1.5%, the water absorption was 0.22, which was 33% lower ...
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According to the research results, under the same mass ratio of material to ball and ball-milling speed, the absolute dry flexural strength and absolute dry compressive …
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The NSGM (1,4) model established in this paper could effectively simulate and predict the absolute dry flexural strength and the absolute dry compressive strength of the ball-milling-modified phosphorus building gypsum; the average relative simulation errors were 12.38% and 13.77%, and the average relative prediction errors were 6.30% and 12.47%.
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tive called gypsum retarder is usually used to prolong the setting time of building gypsum, maintain the plas-ticity of building gypsum for a longer period of time to improve the construction performance[7,8]. Unfortunate-ly, the retarder is negative to the mechanical strength of hardened gypsum. Moreover, the type and addition
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Zhi et al. used alpha-grade high strength building gypsum to prepare gypsum-based self-leveling ... and next, the middle portions of the pastes were soaked in absolute alcohol for 48 h to stop further hydration. ... two series of mortar prisms sized 40 mm × 40 mm × 160 mm were prepared for the determination of the 1-day strength and dry ...
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dry compressive strength of phosphorus building gypsum were compared under different mass ratios of material to ball, ball-milling speed, and ball-milling time, and the NSGM (1,4) model …
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The 2 h flexural strength and absolute dry compressive strength of α-HHs with different modifiers all increased by comparation with the blank sample, and met the requirements of α30 in 《α-High strength gypsum plaster》(JC/T 2038–2010) [29]. The decrease of normal consistency and the increase of the well-crystallized crystals was the ...
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In this experiment, the strength, water absorption and softening coefficient of gypsum test blocks were measured under different admixture conditions using desulphurised building gypsum with …
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Download scientific diagram | The prediction results of absolute dry compressive strength. from publication: Strength Prediction of Ball-Milling-Modified Phosphorus Building Gypsum Based on NSGM ...
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Two groups of the same gypsum samples were prepared. some of them were used for the dry strength (f 1), and the others were soaked in water for the wet strength at 20 ± 2 °C for 24 h (f 2). What' more, the absolute dry mass (m 1) was measured before the absolute dry strength was tested. Thus, the softening coefficient was defined as the ...
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GSL. Traditionally, β -hemihydrate gypsum is commonly blended with cement, α -hemihydrate gypsum or anhydrite to improve its strength (Ma et al. 2018; Jin et al. 2020). Peng et al. (Peng et al. 2012) suggested that 24-hour absolute dry exure and …
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b-gypsum has a significantly lower strength than a-gypsum, it is usually preferred for industrial purposes because the technology of its production is much simpler and more economical [1, 2]. From the chemical point of view, both these types of calcined gypsum are similar. However, they differ in the size of crystals and specific
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the absolute dry flexural strength and absolute dry compressive strength of phosphorus building gypsum firstly increased and then decreased with the increase in milling time. The NSGM (1,4) model established in this paper could effectively simulate and predict the absolute dry flexural strength and the absolute dry compressive strength of ...
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The compressive strength and flexural strength were assessed under the international standard 'Gypsum plasters—Determination of Mechanical Properties' (ISO 3051:1974). It would be advisable to store the specimens, which have a size of 40 mm × 40 mm × 160 mm, in a closed climate chamber immediately after demolding.
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Effects of Several Retarders on Setting Time and Strength of Building Gypsum[J]. Construction and Building Materials, 2020, 240: 117–927. Article ... but little effect on the absolute dry flexural strength was observed. The retarding effect of protein retarder on phosphorus building gypsum (PBG) and desulfurization building gypsum (DBG) was ...
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The paper presents an assessment of the impact of using additives on the strength of a binding material, i.e., building gypsum, and also the phase transformation that takes place in it. Microspheres, aerogel and polymer (HEMC) additives were added to a building gypsum slurry with a water to gypsum ratio of 0.75.
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Abstract. Rapid increases in the production of gypsum waste from the Flue Gas Desulphurization process necessitates that proper impoundments be built with an adequate understanding of the strength behavior of the sedimented gypsum slurry. This article presents laboratory experimental results that describe its physical characteristics and strength behavior. …
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Desulfurization building gypsum underwent production at 170–190 °C, followed by aging before use. The performance characteristics of desulfurization building gypsum are detailed in Table 1 and Figure 1. As shown in the figure, the main mineral phases of desulfurization building gypsum are hemihydrate gypsum and a small amount of anhydrous ...
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Lewry and Williamson [9] reported that the gypsum strength develops during setting via a three-stage process: first a development of an interlocking matrix of dihydrate needles, then a relief …
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The paper presents an assessment of the impact of using additives on the strength of a binding material, i.e., building gypsum, and also the phase transformation that takes place in it. Microspheres, aerogel and polymer (HEMC) additives were added to a building gypsum slurry with a water to gypsum ratio of 0.75. In order to investigate their influence on bending strength, …
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It is necessary to consider the dual problems of poor performance and low production efficiency that stem from the highly utilised water/gypsum ratios in the traditional preparation of phosphorus building gypsum (PBG)-based building materials. These problems cannot be easily overcome because that PBG tends to agglomerate at low water/gypsum …
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the optimum, with the absolute dry flexural strength and absolute dry compressive strength being increased to 8.1 MPa and 20.5 MPa, respectively, which were 50% and 24% higher than those of the
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One important way to recycle phosphogypsum is by preparing phosphorus building gypsum, but its use is limited due to inferior properties compared with cement or natural building gypsum [7, 8 ...
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