Materiales de Construcción

Optimization of the clinker production process in a Spanish cement factory

2025-07-05T14:04:37+02:00

With the aim of manufacturing a clinker that reduces the energy consumption in its grinding, without substantially modifying the behavior of the cement manufactured with it, a characterization methodology based on the Rietveld method has been developed. From this study we have deduced that one of the most influential factors in the specific consumption of the cement mill is the C₃S_M₁ phase. Therefore, efforts will be focused on promoting its formation in the clinker by controlling the MgO content in the kiln feed and the alumina modulus in the clinker.

Impact of ZnO and TiO₂ on C-S-H composition and its correlation with antifungal properties in cement pastes

2025-05-18T21:21:22+02:00

This study presents a self-cleaning cement incorporating zinc oxide and titanium dioxide nanoparticles, used alone or in combination. The objective is to develop high-performance materials suitable for different environments, inhibiting fungal growth while providing self-cleaning properties. In parallel, the impact of these nanoparticles on the mineralogy and structure of C-S-H was examined. Used as partial cement substitutes (0–3% by weight), the pastes were characterized after 28 days of hydration by XRD, XRF, DSC and TG to evaluate reactivity and Ca/Si ratios of the formed C-S-H. Next, a new alternative method for the indirect determination of the Ca/Si ratio of the C-S-H gel in cements is also proposed using three methods. The antimicrobial surfaces were assessed for antifungal activity against Penicillium brevicompactum, Trichoderma reesei and Aspergillus niger on Czapek-Dox agar. Results show that the addition of TiO₂ and ZnO yields fungal-resistant surfaces, promoting hygiene, sustainability and innovation in construction.

Analysis of the properties of concrete produced with solid waste from the washing of ready-mix concrete trucks

2025-07-05T14:46:56+02:00

Concrete batching plants generate various types of waste, including residual slurry from the washing of ready-mix concrete trucks. This study aimed to analyze the mechanical properties of concrete produced with partial substitution (10%, 20%, and 30%) of the binder by the solid waste generated from washing ready-mix concrete trucks. Waste was physically and chemically characterized, and its pozzolanic activity was evaluated. Tests were conducted to analyze the concrete for slump and specific gravity in the fresh state, and compressive strength, water absorption by immersion, void index, and specific gravity in the hardened state. It was concluded that substituting up to 20% of the binder with waste did not significantly compromise the mechanical properties, highlighting the reduction in cement consumption, which brought sustainability advantages. Furthermore, the chemical analysis indicated that the presence of phases such as C-S-H and Portlandite in waste could positively influence the properties of the concrete.

Mechanical characterisation of 3D printed concrete masonry units with high aggregate and mineral addition content

2025-05-18T22:05:12+02:00

The present study aims to expand the understanding of cementitious mixtures with low cement content and high levels of mineral additions and aggregates in order to assess their influence on the constructive characteristics of printing elements representative of structural masonry. The printing parameters and geometry of the pieces were defined to create a structure that can stand without internal bracing, with the goal of making the masonry construction process faster and simpler to print. In the hardened state, water absorption, the compressive and flexural strength of small pieces, as well as the compressive strength of 3DCP blocks and layer bonding, were evaluated. The results demonstrate that, for the parameters adopted in the printing system used, it is possible to construct volumetric masonry elements with mixtures that have higher aggregate content and partial cement replacement with limestone filler and metakaolin, achieving satisfactory results in buildability, mechanical strength, and efficiency.

Printability of stabilized solids for low cement consumption blocks

2024-10-19T19:05:35+02:00

This paper investigates the use of sandy silt in 3D printing by stabilizing it with Portland cement and chemical additives (metakaolin and limestone filler). The goal is to make the soil compatible with the 3D printing process and ensure pumpability. The experimental program began with a reference mixture of soil to cement in a 1:1 mass ratio to achieve a consistency suitable for the extrusion method. The study also examined the content of chemical additives, the water-to-dry material ratio, printing speed, and nozzle height conditions. The analysis included the reduction of cement in two mixtures, T15%C and T20%C, with mass proportions of 0.15:0.85:1 and 0.2:0.80:1. It was confirmed that soil-cement blocks could be successfully produced with compressive strengths of 3.1 MPa and 3.0 MPa for the T15%C and T20%C compositions, respectively, indicating a cement reduction of 87% and 82% compared to the reference mixture (REFT100).

Strength, expansion and microstructural change of fly ash geopolymer mortars containing field Para rubber latex immersed in magnesium sulfate and sulfuric acid

2025-07-16T20:50:49+02:00

Geopolymer mortar from fly ash (FA) and field Para rubber latex (FPRL) with alkaline activators was exposed to 5% magnesium sulfate and sulfuric acid for 90 days with compressive strength. Key parameters assessed include compressive strength, expansion, degradation products, and microstructural changes, analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The study focused on heat-curing time and FPRL content. Samples were cured at 80°C for 0.5, 1, 2, or 4 hours, with FPRL added at 0%, 1%, 2.5%, and 5% by the weight of fly ash. The optimal mixture 1% FPRL with heat curing for 4 hours not only yielded the highest compressive strength but also effectively mitigated the loss of compressive strength caused by exposure to magnesium sulfate and sulfuric acid. Expansion decreased with higher FPRL content and longer curing times. SEM revealed diverse textures based on composition and a porous matrix caused by sulfuric acid erosion.

Mechanical performance of a warm-mix asphalt using sodium silicate-modified asphalt and recycled concrete aggregate

2025-04-30T18:17:46+02:00

The present study evaluated the mechanical performance of a warm-mix asphalt (WMA) by partially replacing the coarse fraction of natural aggregates (NA) with recycled concrete aggregates – RCA. To manufacture the WMA, a sodium silicate (SS) was used to modify and foam the asphalt cement (AC). SS is presented as a novel additive that has not been investigated by the technical and academic community. Based on penetration and softening point tests carried out on modified AC in different proportions (SS/AC=0.25, 0.50, 0.75, 1.0, 1.25, 1.50% by mass), a content of SS/AC=1% was defined as optimum. Viscosity tests, rheological characterization, and Scanning Electron Microscope (SEM) observations were performed on the modified and unmodified AC. Marshall, Indirect Tensile Strength – ITS, resilient modulus, permanent deformation, fatigue, and Cantabro tests were carried out on the asphalt mixtures. The SS allows a 20°C reduction in the mixing temperature, generating WMA mixes that exhibit similar or even better performance compared to the Control HMA. The mixes with RCA exhibited higher resistance in the Marshall test and similar resistance to permanent deformation with respect to the Control mix, but lower resistance to indirect tension, raveling, fatigue and moisture damage.

The effect of replacing aggregates with oyster shell powder on the performance of asphalt concrete

2025-07-05T15:28:52+02:00

In response to the global trend towards achieving net zero emissions, various industries are actively promoting the circular economy. Central to this goal is the strategic utilization of alternative materials to replace virgin materials, thereby reducing carbon emissions during the production and manufacturing processes. This study uses the maximum density line in the FHWA 0.45 power curve to determine the oyster shell powder (OSP) as a substitute for 6% of the fine aggregate and filler in dense-graded asphalt concrete (DGAC). With properties similar to calcium carbonate (CaCO3) and hydrated lime, the inclusion of OSP was expected to enhance the performance of DGAC. For the Experimental Group, 6% of the fine aggregate and filler were replaced with OSP in the DGAC. The control groups used natural aggregate without hydrated lime anti-strip additive (Control Group A) and with hydrated lime anti-strip additive (Control Group B) in the DGAC. The aim was to assess the impact of replacing partial fine aggregate and filler with OSP on the performance of AC. The results indicated that while the Marshall stability, Marshall flow, and indirect tensile strength test values of the Experimental Group were lower than those of Control Group B, they were consistent with the results of Control Group A and complied with AI MS-2 7th. Subsequent evaluations, including the boil test, immersion-compression test, and tensile strength ratio, were conducted to assess moisture damage resistance. This revealed that the Experimental Group and Control Group B exhibited comparable and superior moisture damage resistance compared to Control Group A. Additionally, the Experimental Group outperforms the Control Groups in the Cantabro abrasion test. In summary, the OSP as a substitute for 6% of the fine aggregate and filler enhances the performance of AC, providing effects similar to hydrated lime anti-strip additives and increases moisture damage resistance. This study confirms that using recycled materials such as OSP to replace aggregates in AC, contributing to the goals of energy-saving and carbon reduction in road engineering.

Alkaline activated concrete with recycled asphalt pavement aggregate

2025-02-08T12:49:40+01:00

Geopolymer concrete is an eco-friendly alternative to cement concrete that reduces carbon emissions through the utilisation of industrial waste. This study enhances its sustainability by incorporating recycled asphalt pavement (RAP) aggregates as partial replacements for natural coarse aggregate at 0%, 20%, 40%, 60%, 80%, and 100%, using fly ash and dolomite as binders. The analysis revealed improvements within a specific RAP threshold, with 40% identified as the optimum proportion. Strong correlations (R2 > 0.90) were observed among compressive, flexural, split tensile strength and ultrasonic pulse velocity at 28 and 56 days. SEM-EDS analyses indicated a denser matrix, while XRD and FTIR confirmed the formation of C(N)–A–S–H type gels. These findings demonstrate the potential of RAP in geopolymer concrete, promoting sustainable construction through efficient material reuse.

Evaluation of particleboard with Pine wood particles using polyurethane resin and polyethylene terephthalate

2024-11-22T15:43:09+01:00

The use of recycled polyethylene terephthalate (PET) with pine wood shavings was analyzed in the particleboard manufacture using hot-pressing. 160 °C was considered to avoid moisture build-up in the resin structure and polymer degradation and, property losses. 50% Pine with 40% PET and 10% polyurethane resin (PUR) and 50% Pine with 50% PET and 0% PUR were studied traits. Density, thickness swelling, water absorption, modulus of rupture, modulus of elasticity, perpendicular tensile properties and scanning electron microscopy (SEM) were studied. Density was close to 1 g/cm³, classifying both traits as high-density panels according to the standard code. SEM showed that 160 °C provided an effective envelopment of wood shavings. Physical and mechanical panel properties were superior to the minimum values of standard codes in 10% PUR trait, while they were lower with 0% PUR.