Using the waste materials in the production of the building materials limits the storage of the wastes, burdensome for the environment and landscape, and makes possible to manufacture the materials and products with the use of the less volume of the raw materials. Cement concretes and mortars as the basic building materials offer the broad prospects of utilization of the recyclable or waste materials. The wastes from the iron ore processing are the solid wastes resulting from the process of enrichment of the ore concentrate. The paper presents the results of testing three mortars, in which a part of fine aggregate was replaced with the iron oxide concentrate (IOC) resulting from such a process. IOC has been used as a substitute of 10%, 20% and 30% (by mass) of the fine aggregate. The effect of the concentrate on the mechanical performance of the mortars at the high temperature (up to 600 °C) was also investigated. The IOC is a neutral material, not affecting chemically the process of cement hydration. The addition of IOC slightly improves the strength of the cement mortars (by 5% to 10%). In the case of the larger amount (20–30%) of the addition, the use of superplasticizer is necessary. The IOC significantly improves the high temperature resistance of the cement mortars (300 °C). The cement mortars containing 30% of the IOC addition keep 80% of the initial flexural and compressive strength when exposed to the temperature 450 °C.

The petrographic composition and grain shape variability of beach gravels in the Pogorzelica–Dziwnów coast section (363.0 to 391.4 km of coastline), southern Baltic Sea, Poland were analyzed herein to characterize the lithodynamics and trends of seashore development. Gravels were sampled at 0.25 km intervals, in the midpart of the berm, following an early-autumn wave storm and before beach nourishment. Individual variations in petrographic groups along the shore were investigated. Gravel data were compared and related to coastal morpholithodynamics, seashore infrastructure, and geology of the study area. The contribution of crystalline rock gravels (igneous and metamorphic) was observed to increase along all coast sections, whereas the amount of less resistant components (limestones, sandstones, and shales) usually declined. This effect is explained by the greater wave crushing resistance of igneous and metamorphic components, compared with sedimentary components. Similarly, the gravel grain shape (mainly elongation or flattening) was observed to change, depending on resistance to mechanical destruction, or due to the increased chemical weathering in mainly the limestones, marbles, and sandstones. Observed increase in contribution of discoid and ellipsoid grains is a potential indicator of depositional trends along the coast sections investigated. On the other hand, increased contents of spheroidal and spindle-shaped grains may be related to erosional trends, where intensive redeposition and mechanical reworking of gravels occurs. However, due to the great number of coastal embankments, the petrographic composition and shape parameters of beach gravels do not always clearly indicate the dominant direction of longshore bedload transport. Increased amount of eroded limestone located east of Pogorzelica indicate increased erosion of glacial tills. These sediments are deposited, building the shallow foreshore, with additional redeposition of morainic material towards the shore.

This paper investigates the effects of initial porosity index and load range on the shear strength of a sand sample using direct shear tests performed with a standard direct shear apparatus under varying densities, from loose to compacted. This study focuses on the distinction between the peak $\left({\varphi }_p\right)$ and critical $\left({\varphi }_{cv}\right)$ internal friction angles and their variation with stress level and initial porosity. Results show that the internal friction angle of sand depends on the stress state and initial porosity, reaching a peak value at maximum shear stresses and a critical value at constant sample volume. Higher initial compaction increases the peak friction angle, while higher effective stresses reduce the critical porosity index. The critical state line (CSL) defines the contraction and dilation behaviour of soils, with the critical porosity index varying with average soil stress. The analysis confirmed Bolton’s empirical relationship, linking the peak friction angle with the critical state angle and the dilation angle. This study emphasizes the importance of accurately defining the internal friction angle and considering the nonlinear relationship between shear strength and normal stresses. These findings are significant for geotechnical engineering, particularly in foundation bearing capacity, earth pressure, and slope stability analysis.

Loading dock areas in industrial facilities are often located below the surrounding ground level, which under fluctuating groundwater conditions may lead to adverse hydraulic phenomena. In engineering practice, the impact of groundwater level variations is frequently underestimated, especially when simple ground conditions are assumed. This paper analyzes the causes of pavement deterioration in such zones, focusing on concrete block pavements. The study included a one-year monitoring of groundwater levels and an assessment of their influence on pavement performance. Periodic exceedance of the pavement elevation by the groundwater table was observed, resulting in increased piezometric pressure and vertical water flow through the structure. Although no hydraulic heave was identified, the flow promoted the erosion of the layers. The results highlight the need to account for groundwater fluctuations in pavement design.

Dolina Iny w między Suchaniem a Stargardem Szczecińskim została utworzona w czasie wytapiania się lądolodu z fazy pomorskiej zlodowacenia bałtyckiego. Powstała w miejscu rynny glacjalnej, która utworzyła się w miejscu kopalnych dolin rzecznych.Podczas uzupełniających badań geologicznych związanych z projektem nitki gazociągu Świnoujście – Lwówek Wielkopolski wykonano 20 otworów badawczych w odległościach od 50 do 100m w przekroju poprzecznym przez całą dolinę Iny. Głębokość otworów sięgała od 6 m w strefie krawędziowej do głębokości ponad 30 m w części środkowej doliny. Pozwoliło to na wykonanie dokładnego przekroju poprzecznego przez dolinę.W związku z tym, że w środkowej części doliny natrafiono na znaczną miąższość osadów organicznych i zastoiskowych glin pylastych wykonano sondowanie CPTU oraz pobrano próbki osadów organicznych oraz pylastych zalegających poniżej. Dla pobranych osadów wykonano standardowe badania geotechniczne a dodatkowo dla wybranych 2 próbek określono wiek TL.Wyniki badań potwierdzają istnienie zbiornika sedymentacyjnego wypełniającego dolinę w późnym plejstocenie (gliny pylaste), w którym spokojną sedymentację przerywały zmienne warunki sedymentacyjne. W holocenie osadzały się gytie, namuły a w stropie torfy). Zbiornik stanowiący dolinę Iny wypełniany osadami mineralnymi istniał w czasie funkcjonowania „Zastoiska Pyrzyckiego”.