The influence of a complex application of both plasticizing and air-entraining effects on concrete with polycarboxylate ether superplasticizer (PCE), air-entraining admixture (AIR), or an anti-foaming agent (AF) is analyzed in this paper with considerations for on the air content, workability, flexural and compressive strength, and freezing–thawing resistance of hardened cement mixtures. The effect of the complex behavior of PCE, AIR, and AF on the porosity of hardened cement mortar (HCM) and freezing–thawing resistance was investigated; freezing–thawing resistance prediction methodology for plasticized mortar was also evaluated. The results presented in the article demonstrate the beneficial influence of entrained air content on consistency and stability of cement mortar, closed porosity, and durability of concrete. Freezing–thawing factor K_F depending on porosity parameters can be used for freezing–thawing resistance prediction. With both plasticizing (decrease in the water–cement ratio) and air-entraining effects (increase in the amount of entrained air content), the frost resistance of concrete increases, scaling decreases exponentially, and it is possible to obtain great frost resistance for cement-based material.

The rheological properties and stability of cement‐based materials determine the technological properties of concrete mixtures and significantly influence concrete properties. Polycarboxylate ether (PCE) and other plasticizing admixtures are widely used in construction practice to plasticize concrete mixtures. Experimental research on the rheological characteristics of cement mortar modified with PCE and air‐entraining admixtures (AIRs) was carried out with a rotation rheometer with coaxial cylinders and water bleeding tests. Herschel–Buckley or modified Bingham models were used to approximate experimental flow curves and assess rheological parameters such as yield stress, plastic viscosity, and shear thinning/thickening index. The rheological test was carried out at 5 and 90 min after mixing the cement mortar. The rheological test established that the modification of cement mortar by PCE in a dosage of 0.2% (in dry material) leads to a decrease in plastic viscosity of 25.0% with a reduction in water demand of 18% for the same workability. Modification of cement mortar by AIR in 0.3% dosage leads to a decrease in yield stress by 37.7% and a decrease in plastic viscosity by 35.4% compared to the control specimen without PCE. The combined modification by PCE and AIR admixtures shows a synergistic effect. It leads to a significant decrease in yield stress of cement mortar by 92.2% and a decrease in plastic viscosity to about 0 Pa·s. In addition, there is a significant coefficient of water bleeding reduction up to 0%, when additional water reduction was carried out in the mixture while maintaining the same workability. The cement mortar, with or without PCE and AIR, exhibited shear‐thinning characteristics for up to 90 min after mixing. The solid, liquid, and gas (air) phases’ influence yield stress and plastic viscosity in the analysis mixtures are presented in this paper. It has been established that a modified exponential Mooney dependency can be used to predict the yield stress and plastic viscosity of the modified cement mortar (both plasticized and air‐entrained).

This article explores the durability and cracking defects associated with 3D‐printed concrete, a rapidly emerging technology in construction. As the demand for innovative building techniques grows, understanding the long‐term performance of 3D‐printed structures becomes crucial. The most important properties of these products are the resistance to freezing and thawing and the possibility of cracking during maintenance. A fine‐grained concrete mixture with expanded perlite additive was tested on strength, freezing–thawing resistance, and the reasons for cracking were analyzed during maintenance. Some differences between the results from standard concrete specimens and the results from 3D‐printed concrete were obtained experimentally. During the research, 3D‐printed concrete specimens were produced with industrial equipment, the density and compressive strength were determined, the mass loss of concrete specimens after freeze/thaw cycles was tested. By reducing the water‐to‐cement ratio to 11%, the strength of concrete with expanded perlite additive increased from 68.2 to 71.1 MPa. For concrete with W/C equal to 0.47 after 28 freeze/thaw cycles, the mass loss of 3D‐printed specimens reaches 2.09 and 56 freeze/thaw cycles 9.17 kg/m ² , and large surface defects were obtained. An analysis of the origin and recommendations for preventing cracks from occurring in 3D‐printed products were carried out. The findings underscore the need for optimized mix designs and printing parameters to enhance durability.

This article presents the results of a study on the influence of a three-level dispersed composition of the clinker component of a binder, which includes coarse, medium, and fine fractions, on the physical and mechanical properties of self-compacting concrete (SCC). One of the current challenges in SCC technology is enhancing its durability and resistance to aggressive environments while maintaining self-consolidating properties. Addressing this challenge holds significant engineering importance, especially for infrastructure under freeze–thaw cycles and chemical exposure. The work aimed to determine the optimal polyfractional composition that ensures the maximum packing density of cement binder particles and to assess the changes in the operational characteristics of SCC. A software and calculation complex featuring a three-dimensional modeling algorithm, Drop and Roll, was used to select the optimal composition. Experimental studies were conducted for mixtures with varying fraction contents, differing in average particle sizes of 12 μm, 6.6 μm, and 4.9 μm. It was found that the optimum composition, consisting of 15% of the 1500 cm²/g fraction, 75% of the 3000 cm²/g fraction, and 10% of the 4500 cm²/g fraction, contributes to an increase in compressive strength of 26%, bending strength of 10%, a times two increase in freeze-thaw resistance, a decrease in water absorption, and an improvement in chemical resistance to aggressive environments. The results confirm the effectiveness of optimizing the grain composition of the binder to enhance the durability and performance characteristics of SCC used in aggressive conditions.

The growing demand for low-carbon cementitious materials has increased interest in natural zeolite as a supplementary cementitious material capable of reducing clinker consumption while modifying cement system performance. This study presents an integrated experimental evaluation of natural zeolite-modified cementitious materials by combining rheological behavior, hydration, compressive strength, density, scanning electron microscopy (SEM), and X-ray diffraction (XRD) within a single experimental framework. Natural zeolite was used as a partial replacement for cement at dosages of 5–12.5 wt.%. The results showed that zeolite significantly affected both fresh-state and hardened-state properties. Zeolite increased the rheological resistance of fresh mixtures, shifted the exothermic hydration peak from 12 h to 8–10 h, and reduced the maximum hydration temperature by approximately 8–12%. Among the investigated compositions, the mixture containing 7.5% zeolite exhibited the highest compressive strength (44.9 MPa at 28 days) together with increased hardened density, suggesting more efficient particle packing and matrix development than the reference mixture. SEM observations indicated a more uniform distribution of hydration products in mixtures containing moderate zeolite dosages, while XRD analysis confirmed changes in the crystalline phase assemblage associated with zeolite incorporation. The results demonstrate that moderate natural zeolite replacement, particularly at 7.5%, provides an effective balance between rheological behavior, hydration characteristics, mechanical performance, and microstructural development, highlighting its potential as a sustainable supplementary cementitious material for low-carbon cement-based composites.

This study investigates the effects of waste glass (GL) and silica fume (SF) on the physical, mechanical, and microstructural properties of clay-based ceramic materials produced from low-grade calcite-rich clay loam. Waste glass and silica fume were incorporated at 10–20 wt.%, and the specimens were fired at temperatures ranging from 1050 to 1150 °C. The average density, water absorption, compressive strength, phase composition (XRD), and microstructure (SEM) were evaluated. The results showed that waste glass significantly enhanced the sintering behavior of the ceramic body through liquid-phase formation at elevated temperatures. The average density increased from approximately 1650 to 2200 kg/m³, while water absorption decreased from 6.5% to 3.2%. The optimum firing temperature was 1125 °C, at which the ceramic compositions containing 10 wt.% and 15 wt.% waste glass exhibited no visible deformation and achieved compressive strengths of 32–36 MPa. In contrast, silica fume was less effective as a fluxing additive, resulting in lower strength, increased deformation, and cracking at temperatures above 1100 °C. SEM observations confirmed the formation of a denser, more homogeneous microstructure in the waste glass-modified specimens, while XRD analysis revealed a reduction in quartz content, accompanied by enhanced formation of the diopside and anorthite phases. Among all investigated compositions, the ceramic material containing 10 wt.% waste glass and fired at 1125 °C exhibited the most balanced combination of density, water absorption, and compressive strength, demonstrating its potential for producing high-performance clay-based ceramic materials.