Despite the many benefits associated with the utilization of superabsorbent polymers (SAPs), several drawbacks have been reported. In particular, the effect of SAPs on microstructure, together with its consequences for mechanical properties, is not fully understood yet for some composite materials. This study analyzes the role of SAPs in the formation of the microstructure of lime composites, taking into account their chemical composition. The obtained experimental results show that the particle size and cross-linking density of used SAPs are crucial parameters affecting both the microstructure and mechanical performance of the analyzed composites. Coarser SAPs with low cross-linking density in the dosage of 0.5 and 1 wt.% are found as the most suitable solution, leading even to a slight improvement of mechanical parameters. The secondary porosity formed by swelled hydrogels is identified as a very significant factor since hydrogel-filled voids do not contribute to the strength parameters. The formation of the affected zone around SAP cores depends on the chemical composition of SAPs considerably as the higher cross-linking density influences the desorption rate. Based on achieved results, utilization of SAPs in building materials should be studied at a more detailed level with particular importance on the definition of SAP-related voids and affected zone around SAP particles.

• Klíčová slova
• affected zone, lime-based plaster, mechanical strength, microstructure, secondary porosity, superabsorbent polymer,
• Publikační typ
• časopisecké články MeSH

Mechanically-activated wood-based biomass ash (WBA) was studied as a potential active admixture for design of a novel lime-pozzolan-based mortar for renovation purposes. The replacement ratio of lime hydrate in a mortar mix composition was 5%, 10%, and 15% by mass. The water/binder ratio and the sand/binder ratio were kept constant for all examined mortar mixes. Both binder constituents were characterized by their powder density, specific density, BET (Brunauer-Emmett-Teller), and Blaine specific surfaces. Their chemical composition was measured by X-ray fluorescence analysis (XRF) and mineralogical analysis was performed using X-ray diffraction (XRD). Morphology of WBA was investigated by scanning electron microscopy (SEM) and element mapping was performed using an energy dispersive spectroscopy (EDS) analyzer. The pozzolanic activity of WBA was tested by the Chapelle test and assessment of the Portlandite content used simultaneous thermal analysis (STA). For the hardened mortar samples, a complete set of structural, mechanical, hygric, and thermal parameters was experimentally determined. The mortars with WBA admixing yielded similar or better functional properties than those obtained for traditional pure lime-based plaster, pointing to their presumed application as rendering and walling renovation mortars. As the Chapelle test, STA, and mechanical test proved high pozzolanity of WBA, it was classified as an alternative eco-efficient low-cost pozzolan for use in lime blend-based building materials. The savings in CO2 emissions and energy by the use of WBA as a partial lime hydrate substitute in mortar composition were also highly appreciated with respect to the sustainability of the construction industry.

• Klíčová slova
• binder physical and chemical analyses, environmental assessment, functional properties, industrial waste, lime-pozzolan renovation mortars, pozzolanic activity, wood-based biomass ash,
• Publikační typ
• časopisecké články MeSH

This paper aims to develop recycled fiber reinforced cement plaster mortar with a good workability of fresh mixture, and insulation, mechanical and adhesive properties of the final hardened product for indoor application. The effect of the incorporation of different portions of three types of cellulose fibers from waste paper recycling into cement mortar (cement/sand ratio of 1:3) on its properties of workability, as well as other physical and mechanical parameters, was studied. The waste paper fiber (WPF) samples were characterized by their different cellulose contents, degree of polymerization, and residues from paper-making. The cement to waste paper fiber mass ratios (C/WPF) ranged from 500:1 to 3:1, and significantly influenced the consistency, bulk density, thermal conductivity, water absorption behavior, and compressive and flexural strength of the fiber-cement mortars. The workability tests of the fiber-cement mortars containing less than 2% WPF achieved optimal properties corresponding to plastic mortars (140-200 mm). The development of dry bulk density and thermal conductivity values of 28-day hardened fiber-cement mortars was favorable with a declining C/WPF ratio, while increasing the fiber content in cement mortars led to a worsening of the water absorption behavior and a lower mechanical performance of the mortars. These key findings were related to a higher porosity and weaker adhesion of fibers and cement particles at the matrix-fiber interface. The adhesion ability of fiber-cement plastering mortar based on WPF samples with the highest cellulose content as a fine filler and two types of mixed hydraulic binder (cement with finely ground granulated blast furnace slag and natural limestone) on commonly used substrates, such as brick and aerated concrete blocks, was also investigated. The adhesive strength testing of these hardened fiber-cement plaster mortars on both substrates revealed lime-cement mortar to be more suitable for fine plaster. The different behavior of fiber-cement containing finely ground slag manifested in a greater depth of the plaster layer failure, crack formation, and in greater damage to the cohesion between the substrate and mortar for the observed time.

• Klíčová slova
• adhesive strength, fiber-cement plaster mortar, granulated blast furnace slag, limestone, physical and mechanical performance, waste paper fiber,
• Publikační typ
• časopisecké články MeSH

An anthropometric measurement serves as both an objective assessment and a description of shape and size. Gypsum casts were used for the measurement, along with a statistical evaluation of results, to compare the appearance of patients with a complete unilateral or bilateral cleft lip and palate prior to corrective surgery of their secondary deformity and following this intervention. The evaluated approach was our own modification of rhinoplasty and lip correction, using the remodeling and extension of soft tissues envelope by a skin flap. That is formed from a lip scar after primary reconstruction. Both data of the studied group (n = 49), pre- and postoperative, were compared to a control group of healthy individuals (k = 19), thereby allowing the original severity of the deformity and the morphologic change after surgery to be objectively assessed. Upon correlation to healthy volunteers, we proved that the effect of surgery shifted the monitored parameters into a range found in the normal population. An anthropometric measurement on gypsum casts appeared to be simple, easy to perform, precise, easy to repeat, inexpensive, and yet of a three-dimensional nature with no burden for the patient. It is suitable for verifying the effects of new therapeutic procedures.

• MeSH
• anatomické modely MeSH
• antropometrie MeSH
• chirurgické laloky MeSH
• dospělí MeSH
• jizva chirurgie   MeSH
• kefalometrie MeSH
• lidé MeSH
• mladiství MeSH
• následné studie MeSH
• nemoci rtu chirurgie   MeSH
• nos patologie   MeSH
• ret patologie   chirurgie   MeSH
• rinoplastika MeSH
• rozštěp patra patologie   chirurgie   MeSH
• rozštěp rtu patologie   chirurgie   MeSH
• síran vápenatý MeSH
• studie případů a kontrol MeSH
• výsledek terapie MeSH
• zákroky plastické chirurgie MeSH
• získané deformity nosu chirurgie   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• srovnávací studie MeSH
• Názvy látek
• síran vápenatý MeSH