The primary objective of this study was to assess freeze-thaw resistance of concrete whose structure was modified by varying the water/binder ratio and ground granulated blast furnace slag content, and by air entrainment. The innovative method of the polymer microspheres-based air entrainment was used to provide a stable pore structure.Test results show that the method is very effective both in providing adequate air entrainment and in improving freeze-thaw resistance of concrete. All air-entrained concrete specimens with polymer microspheres (the spacing factor of ≤ 0.25mm) had a good resistance to the action of frost, regardless of the W/S ratio and the slag cement content

People with locomotion difficulties encounter many barriers in a pedestrian environment. Pavement quality has been shown to substantially affect pedestrian satisfaction in general, and its optimal design may contribute to reducing the stigma put on people with impairments. Our research involved a survey assessing perception and attitudes towards pavement quality and characteristics for pedestrian comfort. The classic correlation of the variables based on contingency tables was used to analyse data and to test whether respondents’ perceptions depended on certain profile features. The completion of the statistical inference was the use of advanced algorithms of the correspondence analysis method. The relationships between the variables were assessed optionally using the chi² test. The study results revealed desirable parameters and features of paving surfaces. People who use manual wheelchairs and declare limb loss prefer medium- and large-format concrete pavers with smooth finishing and no bevelling. People with skeletal abnormalities or peripheral neuropathy prefer concrete slabs and surfaces made of small- or medium-sized panels arranged in a regular pattern, made of smooth non-slip concrete with narrow joints. Further laboratory tests are necessary to investigate whether increased water permeability of pavements constructed on eco-friendly base layers can curb damage to the pavement surface and provide long-term durability.

The paper presents the results from the research on self-compacting concrete with different steel fibre type addition. The reference self-compacting concrete mix with water/binder = 0.33 was prepared, then modified with steel fibres in the amounts of 0–60 kg/m3 and air entrained with polymer microspheres (40 μm diameter). The major objective of the research was to determine the effect of steel fibre and air content on the self-compacting concrete mix properties and hardened concrete frost durability. The tests also included internal cracking and scaling resistance evaluation for concrete specimens subjected to cyclic freeze-thaw process − two beams were frozen in air and two beams were partially submerged in water and then frozen. The scaling resistance was tested using the slab method on the specimens with sawn surface and on the specimens with natural finished surface. Non-air entrained steel fibrereinforced concretes, despite their high strength class (C55/67–C60/75) and medium absorption (4.34–5.11%), showed unsatisfactory resistance to internal cracking and scaling tests. The beams partially submerged in water failed after 100 freeze-thaw cycles, which confirms a significant influence of water uptake from moist environment during freeze-thaw cycles and the acceleration of the damage process. Test results indicate that air entrainment with polymer microspheres is a very effective method and allows obtaining very good air pore structure parameters and frost resistance results. The specimens with top − finished surface exhibited less damage in the scaling resistance tests in relation to the specimens with sawn surface.

The paper aims to answer the following questions: What are the trends in streetscape design? And how can streetscape become more resilient to climate change in the coming years? Although the research questions of exploratory nature also challenge theoretical claims, this is a hypothetical study, designed to foster a discussion about the visions of the future streetscape and new technology for an urban sidewalk. It covers a description and a cross-case comparison of an experimental product – the Climate Tile, implemented in Denmark in 2018, and a theoretical solution – the Sponge Pavement – a model system based on the structural soil foundation and permeable surface, evolved as an idea in 2018 in Poland. The cases are examples of innovations selected to describe a new type of water-permeable surfaces matching the urban context. Both solutions share common features: they are in that there is no need to place heavy equipment on the project site; they match the urban context of a dense city, being smooth, resistant and easy to clean. The comparison of the Climate Tile and the Sponge Pavement allowed determining the optimal application for the given solution. It also proved the trend towards the rainwater management-oriented direction of the development of the streetscape of the future. The study results could contribute to the discussion of the streetscape of the future. We would like to focus on the idea of the Sponge Pavement for further development in laboratory tests and as the pilot project.

Conventional maturity methods estimate strength from temperature–time histories using equivalent age and apparent activation energy (Ea). However, determining Ea is time-consuming and requires extensive experimental testing. Moreover, its value depends on cement composition, mixture...

The purpose of laboratory tests was to determine the effect of sodium silicate and selected hydrophobic agents on the basic physical parameters and freeze-thaw durability of mortars made with Sorel cement in variable proportions. In order to determine the mortars’ parameters, samples of the dimensions of 4x4x16 cm and boards of the diameters of 1x4x16 cm were prepared. Parameters such as water absorption, capillary absorption, compressive and flexural strength and frost resistance were tested. Mortar supplemented with sodium silicate in the quantity of 2.6% of all components demonstrated the best properties. None of the other hydrophobic agents that were used to mitigate the negative effects of water on Sorel cement mortars demonstrated such positive properties. Flexural strength tests of all mortar batches, performed on cuboid samples and boards of the thickness of 1 cm, demonstrated a similar improvement in strength. The lowest value of compressive strength was recorded for the reference batch at 46.6 MPa, whereas the highest value was recorded for the second batch containing sodium silicate, at 49.8 MPa. During the testing of frost resistance, the lowest reduction of compressive and flexural strength was recorded for the reference mortar and for mortar with sodium silicate. All mortars were varied in the MgO/MgCl2 ratio and the total amount of water, the observed effects may be caused by other variables. However it is possible to notice the positive effect of selected hydrophobic agents.