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Właściwości mechaniczne cementu fosforanowo-magnezowego z dodatkiem włókien bazaltowych

Pehlivan Ahmet Onur

Cement Wapno Beton

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2021

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R. 26, nr 3

233--241

PL

W pracy badano wpływ włókien bazaltowych na właściwości mechaniczne cementu fosforanowo-magnezowego [CFM]. Mierzono wytrzymałość na ściskanie, wytrzymałość na rozciąganie przy rozłupywaniu, wytrzymałość na zginanie i moduł sprężystości. Stwierdzono, że właściwości mechaniczne ulegają znacznej poprawie wraz z dodatkiem pyłu krzemionkowego, a szczególnie wytrzymałość na rozciąganie przy rozłupywaniu i zginanie, zwiększa się wraz ze wzrostem zawartości włókien bazaltowych. W przypadku mieszanek bez dodatku pyłu krzemionkowego duża zawartość włókien wpływała niekorzystnie na właściwości mechaniczne. Stwierdzono, że dodatek pyłu krzemionkowego wyraźnie zwiększa wiązanie włókien bazaltowych z matrycą CFM. W związku z tym, łączne zastosowanie pyłu krzemionkowego i włókien bazaltowych, okazało się skuteczne. Stwierdzono, że w mieszankach bez pyłu krzemionkowego stosunek molowy magnezji do diwodorofosforanu amonu wynoszący 8, daje lepsze wyniki w porównaniu ze stosunkiem masowym 6. Różnica ta nie była zbyt widoczna po dodaniu do obu mieszanek pyłu krzemionkowego.

EN

In this experimental study, the effect of basalt fibers on the mechanical properties of magnesium phosphate cement [MPC] was investigated. Compressive strength, splitting tensile strength, flexural strength and modulus of elasticity, were introduced. It was observed that mechanical properties were significantly enhanced with the addition of silica fume, especially splitting tensile and flexural strength were enhanced with the increase of basalt fibers. However, for mixtures without silica fume addition, high content of fibers adversely affected the mechanical properties. Silica fume addition was found to be significant in increasing the bonding mechanism between basalt fibers and the MPC matrix. Thus, combined usage of silica fume and basalt fibers was found to be effective. A molar ratio of magnesia to ammonium dihydrogen phosphate of 8 was observed to have better results with respect to a molar ratio of 6, however, this distinction was not very apparent, when silica fume was added to both mixtures.

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Effect of silica fume and calcium carbonate whisker on interfacial behavior of near-surface-mounted FRP with magnesium phosphate cement

Zhang Liwen, Geng Tao, Liu Zhouqiang, Zhang Wenhua, Shang Qinghu

Archives of Civil and Mechanical Engineering

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2020

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Vol. 20, no. 1

14--29

EN

Magnesium phosphate cement (MPC) is a potential substitute of epoxy as an adhesive material due to its advantages in setting time, early strength, and good fire and corrosion resistance. In this study, silica fume (SF) and calcium carbonate whisker (CCW) were employed to improve bond capacity of MPC which were used instead of epoxy in near-surface-mounted (NSM) fiber-reinforced polymer (FRP) systems. A direct pull-out test (DPT) was carried out to investigate bond performances of FRP–concrete interface after incorporating SF and CCW. According to the mix proportion of the MPC, a total of twenty-seven specimens in nine sets were divided into four groups: one group without additive, one group with SF alone, one group with CCW alone, and the last group with SF and CCW combination. Results showed that SF or CCW alone could improve MPC bond capacity, but their excess application would reduce it. SF and CCW combination, however, did not improve bond capacity as effectively as SF or CCW alone. Moreover, the addition of CCW would improve MPC’s bond ductility, with or without the adding of SF, but with the increase in CCW concentration, this improvement effect would decrease. Meanwhile, SF alone lowered its bond ductility.

3

Physicochemical properties of the novel biphasic hydroxyapatite–magnesium phosphate biomaterial

Pijocha D., Zima A., Paszkiewicz Z., Ślósarczyk A.

Acta of Bioengineering and Biomechanics

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2013

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Vol. 15, no. 3

53--63

EN

Besides high-temperature calcium phosphates (CaPs), low-temperature calcium phosphate bone cements (CPCs), due to excellent biological properties: bioactivity, biocompability and osteoconductivity, are successfully used as bone substitutes. However, some disadvantages, related mainly to their low resorption rate and poor mechanical properties result in limited range of applications of these implant materials to non-loaded places in the skeletal system. To overcome this problem, magnesium phosphate cements (MPCs) with high strength have been considered as biomaterials. The main disadvantage of MPCs is that the acid-base setting reaction is an exothermic process that must be strictly controlled to avoid tissue necrosis. In this work, a new composite bone substitute (Hydroxyapatite Magnesium Phosphate Material – HMPM) based on hydroxyapatite (HA) and magnesium phosphate cement (MPC) with sodium pyrophosphate applied as a retardant of setting reaction was obtained. Its setting time was adequate for clinical applications. Combining properties of HA and MPC has made it possible to obtain microporous (showing bimodal pore size distribution in the range of 0.005–1.700 micrometers) potential implant material showing good surgical handiness and sufficient mechanical strength. Effectiveness of sodium pyrophosphate as a retardant of exothermic setting reaction of the new cement formulation was confirmed. After setting and hardening, the material consisted of hydroxyapatite and struvite as crystalline phases. Unreacted magnesium oxide was not detected.