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The performed investigations were focused on analysing the variability of geological-engineering properties in clay soils from central-eastern Europe with regard to microstructures. Thirty-nine soils differing in origin, lithology and microstructure type were selected for analysis. Results of studies on lithological and physical and mechanical parameters were analysed, coupled with quantitative microstructural parameters based on microstructure images. The relationships between lithological, physical and mechanical and pore space parameters were determined with regard to microstructure types. Sediment origin and diagenesis, and soil microstructure and pore space parameters had influence on the geological-engineering properties. Such approach allows for predicting engineering parameters based on soil microstructure types and their pore space parameters.

The paper presents the basic problem related with practical application of carbonate rocks in construction: are carbonate aggregates produced from such rocks favorable for building engineering, particularly for road design and construction? To resolve this problem, (1) the geological-engineering properties of aggregates are presented, (2) the correlation between petrographic and engineering parameters is shown, and (3) a strict correlation between the geological-engineering properties and the freezing-thawing and crushing resistance is recognized. This knowledge has allowed to assess the usefulness of asphalt concrete (AC) made from dolomite and limestone aggregates in the design and construction of road surface structures. The petrography was characterized using optical microscopy and scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscope (EDS). Engineering properties were determined in accordance with European and Polish norms and guidelines. Statistical and design calculations were performed using dedicated software. The petrographic properties, and selected physical and mechanical parameters of the aggregates, were tested to show their influence on the freezing–thawing and crushing resistance. Strong functional relationships between the water adsorption, and the freezing–thawing and crushing resistance have been observed. Aggregate strength decreased after saturation with increasing concentrations of salt solutions. Calculations of AC fatigue durability and deformation allow for reducing the thickness of the road surface structure by about 20% in comparison to normative solutions. This conclusion has impact on the economy of road design and construction, and allows for a rational utilization of rock resources, which contributes to sustainable development of the construction industry.

Cemented stabilized rammed earth (CSRE) is a building material used to build load bearing walls from locally available soil. The article analyzes the influence of soil mineral composition on CSRE compressive strength. Compression tests of CSRE samples of various mineral compositions, but the same particle size distribution, water content, and cement content were conducted. Based on the compression strength results and analyzed SEM images, it was observed that even small changes in the mineral composition significantly affected the CSRE compressive strength. From the comparison of CSRE compressive strength result sets, one can draw general qualitative conclusions that montmorillonite lowered the compressive strength the most, beidellite also lowered it, but to a lesser extent. Kaolinite lightly increased the compressive strength.

The paper presents the results of swell index, swelling pressure and soil suction tests carried out on Neogene clays from Warsaw, depending on the water content, clay fraction, liquid limit, plasticity index, cation exchange capacity, and content of clay minerals and beidellite. These clays are considered expansive soils in Poland, as they are vulnerable to water content variations in the active zone, which result in their volume change and, in consequence, cause damage of foundations and other construction elements. A number of physical, chemical and mineral properties were determined for these clays. The swelling tests were carried out on samples precompacted in Proctor apparatus, at various initial values of water content. The analyses have shown exponential relation of swell index, swelling pressure and suction versus water content. In addition, the investigated relationship between the suction and swell characteristics of tested clays shows good correlation as a power function between these parameters. In addition, validity of correlations between fitting parameters of obtained relationships and soil index properties, such as clay fraction, liquid limit, plasticity index, cation exchange capacity, and content of clay minerals and beidellite, have been demonstrated. The empirical relations are characterized by high values of the correlation coefficient. A very high fit has also been found for a proposed relationship between the swell index and swelling pressure for tested clays

The paper presents the results of swell measurements of Neogene clays (Posnanian clay) from the Mazovia region with different grain size distribution and mineral composition. The study was conducted with model soil with initial moisture contents of 15%, 20%, 25% and 30%. The basic physical properties of clays, their mineral composition and swelling parameters such as free swelling index and swelling pressure were determined. Free swell index was correlated to liquid limit, plasticity index, clay content and water content. A very high fit was found for a proposed relationship between the free swell index and swell pressure which offers an inexpensive method of predicting swell pressure in the preliminary stages of site investigation.