Lech Czarnecki

The paper’s topic is the role of building chemistry in shaping the public trust in construction activities. Building chemistry was defined as the applied natural science in connection with practical activities in the construction industry. The usability in construction was analysed in the context of the basic requirements for building objects. The need for sustainable construction was emphasised, along with the technical challenges posed by thermodynamic conditions. The professional responsibility of the construction engineer was underlined. The paper embeds its topic in the concept of the so-called „Promethean transformation”, which consists in finding a groundbreaking way of energy production. The future lies in activities such as the circular economy and the gradual transformation of the industry (e.g., CO2 emission reductions in cement production). The needs and necessities resulting from the development of modern building chemistry were discussed.

The aim of the present research was to empirically prove that the non-destructive ultrasonic direct method is an effective scientific tool for measuring the maturity of polymer concretes (PC). Maturity is understood as obtaining a stabilised, maximally homogeneous, and dense microstructure of the composite, which is closely related to its mechanical strength. The direct ultrasonic method was used to assess the homogeneity, and thus the quality, of the microstructure of the composites shortly (14 days) after production and after 9 and/or 9.5 years. Different values of the ultrasonic pulse velocity were computed for "young" and several-year-old composites of identical compositions. This study confirmed the authors’ thesis that particular types of PC (with vinyl-ester matrix saturated with finely ground rocks and fossil fuel combustion by-products) show maturation extended up to several years and an additional increase in mechanical strength, despite the long-standing widespread view that polymer concretes obtain their full potential within several days. This indicates the necessity of a thorough examination of the microfiller morphology before its application in PC because it may affect the curing process and strength development. This leads to the second conclusion, that the design rules for PC with microfillers with more developed specific surface areas should be revised because the designed values may be underestimated in relation to the actual values but obtained after a longer time. Graphical abstract

The microstructure of a material is a key factor in determining its properties and durability. This paper highlights key findings from microstructural investigations of concrete-like composites, with a focus on their implementation potential. It introduces a usability function and explores trends in its classification to demonstrate the potential of various microscopic techniques in addressing research questions within the field of building materials. This segment of the analysis focuses on various aggressive factors that affect the microstructures and might cause corrosion of concrete-like composites. The findings underscore that the impact of corrosive agents on Portland cement composites cannot be comprehensively assessed without a detailed investigation of their microstructure, emphasizing the pivotal role of microscopic techniques in the evaluation of concrete-based materials. Furthermore, significant advancements are anticipated in the near future as image analysis becomes increasingly supported by artificial intelligence.

With increasing concrete production, CO₂ emissions rise, and natural resources deplete, creating a need for new material solutions. This article analyzes the feasibility of using green materials, like recycled aggregate (RA) from construction and demolition waste (CDW) to be incorporated into concrete (RAC). The objective of this paper is to determine that the use of RA ensures receiving sustainable concrete in comparison with NA and LA. The sustainability assessment was conducted based on an analysis of the life cycle in terms of the environmental, economic, and public perception aspects. Additionally, the analysis was extended to include two newly introduced indicators: quality of aggregates and concrete performance. A proprietary scoring method based on ideal aggregate characteristics was used, which was enhanced by innovative multidimensional analysis, with credits assigned based on a literature review conducted using artificial intelligence (AI) statistical tools to partially assist in the selection of items. The results could even show that RA outperformed natural aggregates (NA) and artificial (light) aggregates (LA) in the environmental (over 80% of the results) results as well as the economic (over 65%) and public perception categories (over 80%). However, RA ranked second behind NA in terms of quality aggregates and concrete performance, with LA scoring lowest. The results highlight RAC as a satisfactory sustainable option compared with NAC, supporting the circular economy by reducing waste, emissions, and resource consumption. The best solution would be hybrid concrete containing a partial substitute for natural aggregates in the form of recycled aggregates, enabling the advantages of both types of aggregates to complement each other and offset their limitations.

In less than a century, concrete has become the most commonly used construction material worldwide. Today, it is difficult to imagine concrete entirely devoid of polymers. The implantation of polymers into concrete has taken effect in the form of Concrete Polymer Composite [C-PC = PMC + PCC + PIC + PC]. Several milestones are recognised in the development of C-PC. They are discussed here with particular emphasis on the innovative milestones that shaped the use of polymers in concrete. As the difference between polymer cement concrete and ordinary concrete diminishes, the question: “What should the paradigm of C-PC development be?” arises.

The repairs of building structures are inevitable and indispensable. Repairs are used to restore or maintain the usability of existing facilities, often contributing to the extension of their expected service life, increasing the sustainability of building resources. Given that conservation rules are observed, repairs are also used to save monuments. The concept of repair durability brings to the foreground the durability of the repaired structure (after repair): what service life has been obtained/recovered as a result of the repair. Based on the available data (limited set), a generalised distribution function of repair durability was developed, with a disappointing course. This, however, applies (necessarily) to the past. Significant progress was shown to have been achieved in the theoretical and technical fundamentals of technical repair measures. In this situation, a prognostic distribution function was also designed for future repairs according to EN 1504. A rule of thumb called estimating concrete repair durability, CRD was proposed. The risk associated with estimating the durability of repairs was indicated. A reason for optimism is that proactive monitoring of the condition of the structure and, consequently, management of the repair strategy allows to reach the designed life of the structure.

The paper presents pursuits of the truth in building materials engineering. Some definitions of “what truth is” were presented. Partial truths were specified: the truth of scientific reasoning, the truth of scientific assessment, the truth of development directions and the splendour of scientific truth. All categories are addressed to the building materials engineering. In the chapter “Load capacity and stability vs entropy” definitions of entropy and exergy were presented followed by their influence on building construction, illustrated by the “Seneca cliff” and “Energy pyramid”. Chapter 3 presents the truth of scientific reasoning was presented. Three partial truths were indicated: the truth of experimental fact, the truth of scientific reasoning and the truth of scientific presentation. In the chapter “Truth of scientific assessment” two main assessment methods were presented: peer review and a bibliometric parametric assessment as well as their impact on the results and authors. The risks associated with the sole parametric assessment were shown as the two basic factors of a parametric assessment – citation number and Hirsch index – need time to "mature". Additionally, the influence of digitalisation of the assessment of a scientist and a scientific unit on the commoditisation and dehumanisation of science was outlined. In the chapter “Truth of development directions: defined past – fuzzy future” the megatrends observed in technology in the last few decades years were indicated along with new possible trends. Milestones in the development of C-PCs (Concrete-Polymer Composites) were presented. The new paradigm for the new development cycle was proposed.

The laboratory testing of the construction materials and elements is a subset of activities inherent in sustainable building materials engineering. Two questions arise regarding test methods used: the relation between test results and material behavior in actual conditions on the one hand, and the variability of results related to uncertainty on the other. The paper presents the analysis of the results and uncertainties of the simple two independent test examples (bond strength and tensile strength) in order to demonstrate discrepancies related to the ambiguous methods of estimating uncertainty and the consequences of using test methods when method suitability for conformity assessment has not been properly verified. Examples are the basis for opening discussion on the test methods development direction, which makes possible to consider them as ‘sustainable’. The authors address the negative impact of the lack of a complete test models taking into account proceeding with an uncertainty on erroneous assessment risks. Adverse effects can be minimized by creating test methods appropriate for the test’s purpose (e.g., initial or routine tests) and handling with uncontrolled uncertainty components. Sustainable test methods should ensure a balance between widely defined tests and evaluation costs and the material’s or building’s safety, reliability, and stability.