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Rutting (i.e., depressions along the wheel path) is a distress exhibited by flexible asphalt pavements at high in-service temperatures negatively affecting ride comfort and safety. In this regard, the fine asphalt mortar (i.e., bitumen filler and fine sand) plays a key role in the rutting potential of the asphalt mixtures. Given this background, this manuscript presents a small-scale laboratory experimentation aimed at assessing the rutting-related performance of a plain bitumen combined with natural (limestone) or manufactured (steel slag) fine aggregates (size up to 0.18 mm) through advanced experimental and theoretical approaches. Specific rheological tests through dynamic shear were carried out to achieve this goal. The investigated asphalt blends came from a wider research project focused on the implementation of a pavement solar collector (a road system to harvest the solar energy irradiating the pavement). In particular, the present paper aimed at verifying the mechanical suitability of the produced asphalt mixes with respect to permanent deformation resistance. Such a small-scale investigation mainly showed that the previously selected constituent materials did not imply criticisms in terms of rutting response.

This study aims to incorporate building and demolition waste, including lime and crushed granite, as partial alternatives for cement and fine aggregates, respectively, and to devise a plan to reduce their environmental effect resulting from their extensive prevalence in substantial amounts. The use of lime in paste, mortar, and concrete has become a common practice to regulate the environment, save resources, and improve performance in various settings. The first stage of this study investigated the effects of replacing different proportions (0%, 15%, 25%, 35%, and 50%) of lime powder with cement on the physical and mechanical properties of mortar specimens over 7, 28, and 90 days. The next phase of the research examined the impacts of substituting varying quantities (ranging from 10% to 100%) of granite powder in 15 different mixes, while keeping a consistent water-to-binder ratio of 0.45. The last part of the study consisted of an examination of data from previous research on cement mortar and lime-modified cement mortar. This included testing on flowability, standard consistency, setting time, flexural strength, and compressive strength. The acquired data underwent a statistical analysis, which resulted in the development of equations that may predict the mechanical characteristics of changed cement mortar mixes. These equations also highlight the impact of certain physical qualities on compressive and flexural strength.

Steel slag is the main by-product of the steel industry and can be used to produce steel slag fine aggregate (SSFA). SSFA can be used as a fine aggregate in mortar or concrete. However, SSFA contains f-CaO, which is the main reason for the expansion damage of mortar and concrete. In this study, the carbonation treatment of SSFA was adopted to reduce the f-CaO content; the influence of the carbonation time on the content of f-CaO in the SSFA was studied; and the effects of the carbonated SSFA replacement ratio on the expansion rate, mechanical properties and carbonation depth of mortar were investigated through tests. The results showed that as the carbonation time increased, the content of f-CaO in the SSFA gradually decreased. Compared to the mortar specimens with carbonated SSFA, the specimens with uncarbonated SSFA showed faster and more severe damage and a higher expansion rate. When the replacement ratio of carbonated SSFA was less than 45%, the carbonated SSFA had an inhibitory effect on the expansion development of the specimens. The compressive strengths of the specimens with a carbonated SSFA replacement ratio of 60% and 45% were 1.29% and 6.81% higher than those of the specimens with an uncarbonated SSFA replacement ratio of 60% and 45%, respectively. Carbonation treatment could improve the replacement ratio of SSFA while ensuring the compressive strength of specimens. Compared with mortar specimens with uncarbonated SSFA, the anti-carbonation performance of mortar specimens with carbonated SSFA was reduced.

The practical use of recycled concrete aggregate produced by crushing concrete waste reduces the consumption of natural aggregate and the amount of concrete waste that ends up in landfills. This study investigated two methods used in the production of fine recycled concrete aggregate: (1) a method that produces fine as well as coarse aggregate, and (2) a method that produces only fine aggregate. Mortar specimens were tested using a variety of mix proportions to determine how the characteristics of fine recycled concrete aggregate affect the physical and mechanical properties of the resulting mortars. Our results demonstrate the superiority of mortar produced using aggregate produced using the second of the two methods. Nonetheless, far more energy is required to render concrete into fine aggregate than is required to produce coarse as well as fine aggregate simultaneously. Thus, the performance benefits of using only fine recycled concrete aggregate must be balanced against the increased impact on the environment.

The rapid expansion of construction, fueled by industry and economic and population growth, has exacerbated the challenge of managing construction waste, especially concrete waste. One promising solution lies in the utilization of recycled fine aggregate (RFA), especially in combination with the emerging geopolymer technology, an innovative alternative to traditional cement. This study systematically explores the effects of incorporating varying qualities and quantities of RFA into geopolymer mortars. By using GGBS and FA as raw materials and replacing natural aggregates (NA) with RFA at different rates (25%, 50%, 75%, and 100%), the research investigates the fresh properties, mechanical characteristics, and drying shrinkage of geopolymer mortar. Key findings reveal that RFA significantly influences the flowability of geopolymer mortar: when RFA content is above 75%, preprocessed RFA (with particles below 0.15 mm removed) has substantially improved flowability, increasing it more than 20%. The critical impact of RFA preprocessing on enhancing mechanical properties and the higher the inclusion level (above 75%), the more pronounced is the advantage in enhancing the compressive strength compared to unprocessed RFA. Additionally, RFA was found to contribute to a denser interfacial transition zone (ITZ) than natural aggregate, which helps maintain the compressive strength at increased RFA dosages. Contrary to findings in cement mortar, a positive correlation exists between pore volume and compressive strength in geopolymer mortar incorporating RFA. This study underscores the potential of refined RFA preprocessing methods in advancing sustainable construction, highlighting avenues for the broader application of RFA in geopolymer mortar.

This research investigates the viability of high-strength Recycled Concrete Aggregate (RCA) sourced from demolished structures containing high-strength concrete as a substitute for natural fine aggregates (NA) in cementitious mortar applications. Concrete specimens (40 × 40 × 160 mm) were prepared in a controlled environment with varying percentages of RCA replacing NA, ranging from 0% to 100% in 10% increments. The resulting RCA aggregates exhibited lower weight for sizes from 0.01 to 1 mm compared to NA, and for 1 to 3 mm sizes, RCA weights were 145% to 177% higher than SS aggregates. After curing for 28 days, flexural and compressive strength tests were conducted on the batches. The average compressive strength for the 0% RCA batch was 66.26 MPa, while the 50% RCA batch showed the closest average compressive strength at 63.10 MPa. Batches with varying RCA levels displayed compressive strengths between 49.52 and 58.18 MPa. The highest flexural strength was observed in the 0% RCA batch, with the closest result for a batch containing RCA being the 50% RCA batch.

This study determines the effect of spent garnet as a replacement for natural sand in 3D-printed mortar at early ages. Five mixes with different spent garnet amounts were prepared (0%, 25%, 50%, 75% and 100% by volume). The ratio of binder to aggregate remained unchanged. In all mixes the water/binder ratio was assumed as a constant value of 0.375. Tests were performed to confirm the printability of the mix (a path quality test using a gantry robot with an extruder). Determinations of key buildability properties of the mix (green strength and Young’s Modulus) during uniaxial compressive strength at 15 min, 30 min and 45 min after adding water were conducted. A hydraulic press and the GOM ARAMIS precision image analysis system were used to conduct the study. The results showed that an increase in spent garnet content caused a decrease in green strength and Young’s Modulus (up to 69.91% and 80.37%, respectively). It was found that to maintain proper buildability, the recommended maximum replacement rate of natural sand with garnet is 50%. This research contributes new knowledge in terms of using recycled waste in the 3D printing technology of cementitious materials.

Due to the global growth of the construction industry, the use of concrete has increased rapidly. Consequently, the depletion of natural aggregates, which are essential components of concrete, has emerged as a critical issue. Simultaneously, the construction of marine structures has recently increased due to population growth and climate change. This trend highlights the growing demand for durable and sustainable construction materials in aggressive environments. To address the depletion of natural aggregates, extensive research has focused on artificial lightweight aggregates produced from industrial waste. However, the high porosity and low compressive strength of artificial lightweight aggregates have limited their effectiveness in ensuring the performance of sustainable marine structures. In this study, a high-performance mortar (HPM) incorporating artificial lightweight fine aggregates (ALWFAs) was developed to address the depletion of natural aggregates and to serve as a protective layer material in marine environments. To enhance the physical properties of ALWFAs, the aggregates were coated with epoxy-TiO2 coatings applied to both their internal voids and external surfaces. The effectiveness of this enhancement was assessed by comparing the performance of mortars prepared with uncoated and coated ALWFAs. The HPM was evaluated for its porosity, compressive strength, split tensile strength, and chloride diffusion coefficient. The results showed that increases in the ALWFA replacement ratio led to a general reduction in performance. However, a comparison between uncoated and coated ALWFAs revealed that the coated aggregates led to improvements of up to 4.13%, 49.3%, 28.6%, and 52.0% in porosity, compressive strength, split tensile strength, and chloride diffusion coefficient, respectively. The study results are discussed in detail in the paper.

In this paper, the durability of cement mortar prepared with a recycled-concrete fine powder (RFP) was examined; including the analysis of a variety of aspects, such as the carbonization, sulfate attack and chloride ion erosion resistance. The results indicate that the influence of RFP on these three aspects is different. The carbonization depth after 30 days and the chloride diffusion coefficient of mortar containing 10% RFP decreased by 13.3% and 28.19%. With a further increase in the RFP content, interconnected pores formed between the RFP particles, leading to an acceleration of the penetration rate of CO2 and Cl−. When the RFP content was less than 50%, the corrosion resistance coefficient of the compressive strength of the mortar was 0.84–1.05 after 90 days of sulfate attack. But the expansion and cracking of the mortar was effectively alleviated due to decrease of the gypsum production. Scanning electron microscope (SEM) analysis has confirmed that 10% RFP contributes to the formation of a dense microstructure in the cement mortar.

Global temperatures have led to an increasing need for air conditioning systems. So, because of this fact, buildings have been improved in terms of their thermal and energy efficiency. Regarding this, the Brazilian standard ABNT NBR 15.575-4/2013 set minimum parameters for the thermal transmittance and thermal capacity of sealing elements, which allow classifying the thermal efficiency of the building. In order to comply with the requirements, the usage and study of lightweight construction materials have been in focus. An example of these materials is vermiculite. The present research reviewed articles about expanded vermiculite. The study involved the examination and comparison of various articles to analyze the properties of vermiculite and the impact of its usage on coating mortars. It was possible to verify that using vermiculite in mortars caused bad workability and a decrease in mechanical strength. However, the porosity and water absorption in mortars increased. Additionally, it reduced the specific weight and the thermal conductivity of the mortars, allowing for a better thermal insulation of the rooms. As an alternative to decreasing the negative effects of vermiculite, it is possible to use chemical admixtures, mineral additions, and mix design with a greater consumption of binder or a combination of particle sizes.