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The adhesive strength of non-structural lime-based grouts used to stabilise sensitive, detached, decorative plasters is an important mechanical property. However, it is difficult to determine it due to the lack of suitable standard test methods. The existing standard procedures are mainly aimed at testing the properties of hydraulic binders and are not suitable for injection grouts or mortar specimens based on a lime binder. In the present study, the focus is on a comparison of the pull-off results between the standardised method (EN 1015-12) performed on pre-drilled specimens on sandwich panels (PMS) and the modified method using sandwich discs (DSS). It was found that the modified method with sandwich discs (DSS) achieved an up to 58 % higher adhesive strength than the standard method with sandwich panels. In the sandwich-panel specimens, fracture occurred in the grout since pre-drilling reduced the cohesive strength of the grout. For the sandwich discs (DSS), fractures occurred predominantly at the interface between the mortar and the grout.

This paper investigates the origin of increased strength and water resistance of air lime mortar prepared by Triassic dolomite aggregate when exposed to humid or wet environments. The mortar specimens were exposed to various ageing conditions and analysed using petrographic and scanning electron microscopy equipped with X-ray microanalysis. Parallel to these analyses, X-ray powder diffraction and strength tests were performed on the specimens. It was revealed that reactions associated with the dedolomitisation process of the dolomite grains in the lime binder (hereafter alkali-carbonate reactions or ACRs) are the source of the improved strength and water resistance. An increasingly alkaline environment accelerated the ACRs substantially. Two parallel processes during the ACRs (dedolomitisation and CaCO3 dissolution/reprecipitation) were described in detail. Ageing temperature decisively influenced the kinetics of the dedolomitisation and dictated the path of the CaCO3 dissolution/reprecipitation process. After two years of ageing in a water-saturated environment at 60 °C, air lime mortar retained a great deal of its initial mechanical strength, and at 20 °C its strength was considerably increased. This somewhat unexpected observation was explained as being a result of microstructural changes and/or phase transitions.

Dry hydrated lime is an air binder often used in architectural injection grouts. This study compared the influences of three commercially available dry hydrated limes on the injection grouts’ workability and mechanical properties. The main differences between the limes were in their chemical and mineralogical composition and Blaine specific surface area. The grouts were composed of dry hydrated lime, finely ground limestone filler, water, and super plasticiser. Subsequent results obtained revealed that the Blaine specific surface area is not directly related to the fresh grout properties. Grain size distribution and shape of lime particles and their aggregates in the water suspension are key parameters influencing the following fresh grout properties: fluidity, injectability, the mixture’s stability, and water retention capacity. However, the lime injection grouts’ mechanical strengths were higher in relation to an increase in the content of portlandite and the Blaine specific surface area of the dry hydrate.

Blended cements might change the chemistry of the pore solution and subsequently affect the corrosion of steel in concrete. Pore solutions were extracted, analyzed and compared from mortars made of CEM I, CEM II, CEM III and CEM IV cements. Three combinations of carbonation and chloride states were studied, i.e., non-carbonated without chlorides, non-carbonated with chlorides and carbonated with chlorides. Different electrochemical and spectroscopic techniques were used to study the electrochemical properties, the type and the extent of the corrosion products, as well as the type and the extent of the corrosion damage. It was confirmed that the most corrosive environments were pore solutions extracted from the carbonated mortars with chlorides. In this environment the highest corrosion rate was observed for the CEM III pore solution, and the lowest for the CEM I. The extent and the type of corrosion products and the corrosion damage varied according to the environment.

Microstructure development of concrete, mortar, and paste scale of cement-based material (CBM) during the early hydration stage has a significant impact on CBM’s physical, mechanical, and durability characteristics at the high maturity state. The research was carried out using compositions with increased autogenous shrinkage and extended early age period, proposed within the RRT+ programme of the COST Action TU1404. The electrical conductivity method, used to follow the solidification process of CBM, is capable of determining the initial and final setting time, and the end of the solidification process acceleration stage for the paste and mortar scale. Simultaneous ultrasonic P- and S-wave transmission measurements revealed that the ratio of velocities VP/VS is highly dependent on the presence of aggregates—it is considerably higher for the paste scale compared to the mortar and concrete scale. The deviation from the otherwise roughly constant ratio VP/VS for each scale may indicate cracks in the material. The non-linear correlation between the dynamic and static elastic moduli valid over the three scales was confirmed. Additionally, it was found that the static E-modulus correlates very well with the square of the VS and that the VS is highly correlated to the cube compressive strength—but a separate trendline exists for each CBM scale.

Injection-grout density is an important parameter when its additional weight leads to consolidated decorative plasters becoming damaged. This is especially evident in larger detached areas. In this study, thin-walled soda&ndash, lime&ndash, borosilicate glass microspheres were used as a density-reducing constituent in hydrated lime grout mixtures. The normal density grout composition&mdash, one volume part hydrated lime and three volume parts inert limestone filler with 0.5% of the polycarboxylate ether-based superplasticiser&mdash, was modified with partial substitution of the limestone filler with lightweight glass microspheres. The following volumetric proportions between limestone filler and glass microspheres were used: 100%:0%, 67%:33%, 50%:50%, 33%:67%, and 0%:100%. With the increase of the glass microspheres&rsquo, volume, the density of the grout is gradually reduced. Furthermore, there is a decrease in the stability and injectability of fresh grout. In its hardened state, the grout&rsquo, s strength again reduces gradually, but there is no significant change in the grout&rsquo, s water absorption and water-vapour resistance. The resistance of the grout to freezing&ndash, thawing and heating&ndash, cooling cycles using distilled water or salt solution is highly improved when the microspheres are present.

Supplementary cementitious materials are known to refine the pore structure of concrete and accelerate the carbonation progress. The combination of the two processes can have both beneficial and disadvantageous effects on corrosion, especially when chlorides are also involved. In this study the corrosion properties of multiple blended cements were evaluated in carbonated and non‑carbonated states, with chlorides introduced through cyclic ponding. The examination involved monitoring the propagation phase, determining the microstructural properties of cements, and assessing the final corrosion damage. The results showed that the steel in the blended cements initially had a relatively high corrosion activity, which later decreased compared to the OPC. This stabilisation was presumably due to the beneficial changes to the pore structure. Carbonation had a significant impact on the corrosion, with carbonated mortars revealing shallower damage over a larger surface area. This effect was more pronounced for blended cements that exhibited greater susceptibility to carbonation.

Round Robin Testing (RRT) is a well-known method for assessing the reproducibility of a test or verification of a new test procedure of almost any kind. In the EU funded network COST Action TU1404 ‘‘Towards the next generation of standards for service life of cement-based materials and structures”, an Extended Round Robin Testing program (RRT+ ) was planned as a fundamental tool to obtain input data for a range of concrete properties and validate non-standardised testing techniques. In this paper, detailed information on the planning, conduction and analysis of Phase 1 of the RRT+ is presented. The aim of Phase 1 was to define and confirm the best practice for creating a comparable reference concrete mix for RRT programmes. With a total of 45 laboratories from Europe, Japan and Canada, RRT+ was one of the most extensive round robin testing programmes targeting cement-based materials., The authors also acknowledge the financial support of EDF, France; CEVA Logistics, Austria and Germany; OeBB Infra, Austria; Staten Vegvesen, Norway and Schleibinger Gerate, Germany. The support of the research network COST TU1404 (COST Association) is also gratefully acknowledged.

The paper summarizes the results of laboratory tests that were performed on samples of extruded polystyrene foam (XPS). The aim of the investigation was to determine the mechanical characteristics which are essential for the seismic analysis of modern low-energy building structures, where XPS boards are used as a thermal insulation layer beneath the building's foundations. As well as this, the shear behaviour of differently composed thermal insulation (TI) foundation sets was investigated, and their friction capacity estimated. The results showed that, in general, XPS material with higher compressive strength also possesses higher shear strength. Sliding between individual components of TI foundation set was revealed to be a likely failure mechanism in the case of building structures that are founded on a TI layer when subjected to strong earthquake loadings.

U radu se prikazuje usporedba reoloških parametara 26 različitih svježih betona mjerenih pomoću dva koaksijalna cilindrična reometra ConTec Viscometer 5 i ICAR Rheometer. Provedeno je i mjerenje konzistencije slijeganjem i konzistencije rasprostiranjem. Statističke analize dobivenih rezultata pokazuju dobru korelaciju između dva reometra za granicu tečenja i plastičnu viskoznost. Provedenim istraživanjem ustanovljena je jaka korelacija između granice tečenja i obradivosti te slaba korelacija između obradivosti i plastične viskoznosti., The comparison of rheological parameters for 26 different types of fresh concrete, measured with two co-axial cylinder rheometers ConTec Viscometer 5 and ICAR Rheometer, is presented in the paper. The consistency by slump test and flow table test was also measured. Statistical analyses of results show good correlation between the two rheometers for the yield stress and plastic viscosity. During this study, a strong correlation was established between the yield stress and workability, while the correlation is weak between the workability and plastic viscosity.

In this paper, the applicability of the ultrasonic wave transmission method to estimate the initial setting time of an arbitrary cement paste is discussed. Ultrasonic pulse velocity measurements were fully automated and measured continuously. The Vicar Needle Test was used in order to determine the initial setting time of cement pastes. Different cement pastes were prepared in order to check the influence of the water/cement ratio, type of cement, curing temperature, cement fineness, and some clinker compositions, on the relationship between the initial setting time and ultrasonic pulse velocity. It was found that the initial setting time of an arbitrary cement paste can be estimated very accurately by the time the first inflection point appears on the ultrasonic pulse velocity curve. Moreover, it can be estimated quite accurately by the time the ultrasonic pulse velocity reaches a fixed value, close to the value of the ultrasonic pulse velocity in water.

Este artigo apresenta experiencias obtidas no decorrer da aplicacao e teste de diferentes fachadas em cal pura que poderao vir a ser usadas com sucesso no restauro de edificios historicos na Eslovenia. Cada fachada de cal e composta por uma camada de revestimento (argamassa grosseira), uma camada de acabamento (argamassa fina) e uma camada protectora de agua de cal. Para a concepcao das argamassas foram escolhidos diferentes tipos de cal, de producao industrial e tradicional, com base em estudos preliminares dos autores e em experiencias de uma pequena empresa (SE) envolvida no estudo. As camadas que compoem as fachadas foram aplicadas na parede norte - a mais problematica - de uma capela historica em alvenaria de pedra ordinaria. Esta capela pertence ao castelo de Crnelo, construido no final do seculo XVII em Turnse, uma vila nao muito distante de Liubliana, capital da Eslovenia. As fachadas foram efectuadas por trabalhadores habilitados da SE, com um intervalo de cerca de um ano entre a aplicacao das camadas de revestimento e de acabamento, e com a camada protectora de agua de cal pigmentada aplicada um a tres dias apos a execucao das camadas de acabamento. Previamente a aplicacao das camadas de acabamento, foram conduzidas inspeccao visual, medicoes de absorcao de agua e determinacao da profundidade de carbonatacao nas camadas de revestimento. Identicos testes in-situ foram subsequentemente conduzidos nas camadas de acabamento. Ate agora, paralelamente aos testes in-situ, foram efectuados em laboratorio testes de resistencia a compressao e de absorcao de agua sobre prismas preparados com as argamassas grosseiras.

Injektiranje je jedan od najdjelotvornijih, a često i najprikladnijih postupaka za ojačanje zidova starih zidanih građevina. Da bi se ocijenio utjecaj raznih vrsta injekcijskih smjesa na mehanička svojstva zidanih građevina, obavljeno je ispitivanje in situ postojeće zidane građevine. Dobiveni rezultati korišteni su za ocjenu seizmičke otpornosti građevine pomoću metode postupnog guranja, uz primjenu pristupa katnog mehanizma i mehanizma globalnog odziva. Prihvatljivije vrste injekcijskih smjesa usporedive su s cementnim injekcijskim smjesama. Dobiveno je da se pristupom globalnog odziva postižu realniji rezultati čak i kod niskih zidanih građevina., Grout injection is one of the most effective and often most appropriate techniques for strengthening of old stone masonry walls. In order to assess the influence of different types of injection grouts on the mechanical properties of masonry, an actual stone masonry building was tested in-situ using various testing methods. The results obtained were used to evaluate seismic resistance of a building using the pushover method, and considering the storey mechanism approach and the global response mechanism. More compatible types of grouts can match cement grouts. The results show that the global response approach provides more realistic results even for low-rise masonry buildings.

Injektiranje je jedan od najdjelotvornijih, a cesto i najprikladnijih postupaka za pojacanje zidova starih zidanih građevina. Da bi se ocijenio utjecaj raznih vrsta injekcijskih smjesa na mehanicka svojstva zidanih građevina, obavljeno je ispitivanje in situ postojece zidane građevine. Dobiveni rezultati koristeni su za ocjenu seizmicke otpornosti građevine pomocu metode postupnog guranja, uz primjenu pristupa katnog mehanizma i mehanizma globalnog odziva. Prihvatljivije vrste injekcijskih smjesa usporedive su s cementnim injekcijskim smjesama. Dobiveno je da se pristupom globalnog odziva postižu realniji rezultati cak i kod niskih zidanih građevina

The knowledge of the structural behaviour of existing masonry requires a multilevel approach, with proper application of different diagnostic and assessment methodologies. The paper presents successful application of the results of in-situ tests on modelling the behaviour of historical structures. In order to obtain reliable material parameters for the application of different numerical models, different test methodologies a combination of Destructive Tests (DT), Minor Destructive Tests (MDT) and Non-Destructive Tests (NDT) were performed. Following this, two different models were applied for the assessment of seismic resistance of Pišece Castle – structural element model (SEM) for non-linear seismic analysis and 3D finite element model (FEM) for linear analysis by means of modal response spectrum analysis. The results of numerical analysis provided valuable information of the loadbearing capacity of structures, their seismic resistance as well as possible causes for the observed crack patterns.