Sand Quarry Research Articles

The Impact of Natural Fibers on Thermal Resistance and Spalling in High-performance Concrete

This article presents an experimental approach to evaluate the effectiveness of palm fibers as a natural innovative solution to enhance the thermal resistance of high-performance concrete (HPC) under fire conditions. The utilization of palm fibers aims to promote local materials, since locally sourced materials may be more affordable due to their abundance. Four different high-performance concrete formulations were tested. The first, called HPCSF, which is composed of fibreless silica fumes, served as a reference mix. The second, HPCPSF, included the addition of polypropylene fibers to silica fume. The third, HPCDFSF, integrates date palm fibers with silica fume. Finally, the fourth, HPCPQSSF, combined polypropylene fibers with varying amounts of quarry sand and silica sand, in addition to silica fume. The results of the fire resistance tests show that the incorporation of palm fibers into the concrete mixture improves structural strength, reduces spalling, prevents crack formation under high-temperature conditions, and increases fire resistance in HPC.

Community-Based Participatory Research on Urban Environmental Conflicts: Sand Quarries in Northern Bogotá

The paper is about community-based participatory research on environmental conflicts about sand quarries in northern Bogotá. Community-based participatory research is applied to understand the environmental conflicts of mining activities. The approach was suitable for improving the relevance and acceptance of research in the local community. It invited community members to participate and uphold their views about the social conflicts and environmental impacts arising from mining activities. The findings highlight the need for participatory environmental governance, integrating local communities and power relations analysis in environmental decision-making.

Восстановление почвенного покрова на техногенной территории в условиях нижнего Дона

The article presents an analysis of the dynamics of soil cover formation in a technogenic territory. The humus content in the soil varies from 1.42 to 2.34% (Table.1), there was an increase in the humus content over the years of the study. The content of nitrate nitrogen and exchangeable potassium in the soil is very low. Organic residues are decomposing in the turf horizons, so the content of mobile phosphorus is average. The content of carbonates increases from 0.68 to 1.12% over the years of research, the quarry soils are not saline, the cationic-anionic composition of the aqueous extract is chloride-sulfate. The structural condition of the quarry soils is good. Perennial herbaceous vegetation has a beneficial effect on the structural condition of the soils. The soil cover has been radically disrupted at the abandoned sand quarry, therefore, at this stage, vegetation and soils are gradually being restored. The soils of the abandoned sand quarry are at the stage of initial soil formation. Keywords: SOIL COVER, TECHNOGENIC TERRITORY, SOIL FORMATION, SAND QUARRY, SOIL RESTORATION

Study of the effect of instant cooling with water on the resistance of concrete exposed to high temperatures

This study investigates the impact of water-cooling versus conventional air-cooling on the compressive strength of concrete after exposure to high temperatures (800C0) for 15 minutes in an electric furnace at the Libyan Iron and Steel Company. The concrete mixtures utilized fine aggregates sourced from sand quarries in the Aburoya area of Misurata City and coarse aggregates from a quarry near Bani Walid City. A total of 27 samples were prepared and subjected to a 28-day moisture treatment. The samples were categorized into three groups based on their target compressive strengths: C25, C30, and C35, with nine samples in each group. For each group, six samples were exposed to high temperatures; three were then cooled immediately with water, while the remaining three were allowed to cool gradually at room temperature. An additional three samples were maintained as reference specimens that did not undergo high-temperature exposure. Upon testing, the results indicated that the samples cooled by water exhibited lower compressive strength compared to those that were gradually cooled at room temperature. Additionally, the reference samples demonstrated the highest compressive strength. Notably, the findings revealed an inverse relationship between the cooling method and concrete strength, with higher compressive strengths corresponding to decreased overall strength due to the cooling methods applied. Keywords: High temperatures, Water cooling, Conventional air-cooling, Compressive strength, Reference samples.

Identification of Technosols formed from industrial dust in the area of Yazd city (Central Iran) by ground-based radiometry

Intensive industrial development in the form of metallurgical plants and quarries for mining of mineral resources in the vicinity of the city of Yazd resulted in significant dustiness of the ground layer of atmosphere and accumulation of industrial dust on the soil surface. At the locations of alloy steel production facilities, dust composition was dominated by particulate matter less than 1 μm (PM1), while near sand quarries, dust particles less than 10 μm (PM10) were predominant. The dust from these sources also differs in chemical composition (iron/silicon content ratio, pH). Registration with a pyranometer with a dark green filter with transmittance at a wavelength of 550 nanometers with a time interval of 20 seconds at a speed of 30 km/h during the movement along the specified routes allowed authors to identify zones with a stable increased content of particles of different sizes in the near-surface atmosphere. Sampling soil pits in these zones confirmed the presence on their surface of layers of dust deposits with a thickness of more than 5 cm, which allows them to be attributed to Technosols in accordance with the WRB soil classification. The soil map of the research area was compiled at a scale of 1 : 25 000 with the reflection of Technosols participation in the soil patterns. According to the map, more than three quarters of the study area are soil complexes including Technosols. Arid climatic conditions of the region lead to the accumulation of dust on the soil surface, which are practically not transformed and not removed from the soil, which results in their degradation and deterioration of the environmental conditions. Dust accumulation on the soil surface affects the state of vegetation cover of the region, which serves as a basis for indirect satellite indication of dusting zones. The method of revealing the dust layer on the soil surface based on the assessment of dustiness of the near-surface atmosphere using pyranometer can serve as a good complement to remote sensing methods.

Influence on impact strength and chloride permeability of concrete made with cementitious material and artificial sand

The over usage of natural sand and cement has negative social and ecological effects. To address this, by-products of industrial wastes known as pozzolanic materials, including as fly ash, GGBFS, silica fume, and metakaolin, can be utilised with the manufactured sand in place of the natural fine aggregate and cement. As a result, the current research project discussed in this article examines the viability of replacing cement in concrete with pozzolana and crushed sand. Thus, this will address two issues at once: the large-scale use of pozzolanic materials and the preservation of natural sand quarries. The main objective of this experimental investigation is to find out the impact and durability properties of concrete produced by replacing natural sand by manufactured sand in varying percentages like 0, 10, 20, 30, 40, 50, 60 70, 80, 90, 100, and 20% cement replacing with pozzolanic materials. Cylindrical disc 150 mm diameter and 65 mm thick was tested for impact strength and chloride permeability 50 mm thick and 100 mm diameter samples were cast. The 28-day impact strength and chloride permeability of concrete mixed by partially substituting cement with pozzolan and partially substituting natural fine aggregate with artificial sand were tested. For the various concrete mix proportions, the findings for impact strength and chloride permeability were examined and contrasted with standard concrete. The results of this study show that substituting 20% of the cement with silica fume and 60% of the natural fine aggregate with M-sand results in concrete that has a maximum impact strength and a minimum chloride permeability. An ANN Model was developed using the experimental values. For design of model 400 result values where used, 20% results used for testing purpose and 80% results used for ANN model training. Calculated using the product of 25 input data. The ANN model’s results offer a precise elastic prediction of the impact strength and chloride iron pass ability of concrete mixed with substituting industrial cementitious waste for cement and artificial sand with naturally occurring fine aggregate. The findings of this study help to reduce the extraction of non-renewable natural recourses and the environmental impact of industrial waste by preparing more sustainable concrete.

Evolution of Weichselian aeolian strata on a coarse-grained substrate in a rugged piedmont topography: A case study from the foothills of the eastern Sudetes Mts., Czechia

The southern margins of the northern European loess belt on the foothills of Eastern Sudetes Mountains are less explored sedimentation zones. This study provides new data about the development of aeolian silty-sandy sediments overlying the glaciofluvial succession on the rugged topography near the village of Kolnovice. The Kolnovice sand quarry (360 × 200 m), which lies at the margin of the upland plateau, is the only active-mined outcrop on the foothills of the Eastern Sudetes and is large enough to study Pleistocene (peri-)glacial sediments. To examine the origin of these sediments, we applied lithofacies analysis (both macro-description of outcrop walls and micromorphological study of thin sections) and surface analysis of quartz grains. Periglacial structures have been identified within the sediments, allowing us to further interpret the post-sedimentary evolution of the sedimentary succession. The studied sediments resulted from colluvial redeposition of aeolian sediments, which was controlled particularly by the topography, glaciofluvial substrate, and climatic conditions. The underlying glaciofluvial sediments are the most crucial source of the studied sediments, although the fine-grained material could have been transported from more distant areas.

Assessment of the physical and mechanical characteristics of sand for the production of foam concrete using the two-stage foam injection method

The article presents the results of experimental studies of the properties of quarry sand to assess their suitability for use in the production of foam concrete. The sites of quarry sand extraction in the territory of the Akmola region are analyzed and their physical and mechanical characteristics are characterized. Evaluation of the physical and mechanical characteristics of sand was made for four types of sand. The main evaluation parameters were: particle size distribution, homogeneity, shrinkage, density and moisture content of sands. The results of the study showed that the physical characteristics of sands vary depending on their type, which indicates the differences in the natural composition and properties of these materials. Evaluation of the homogeneity of the different types of sands confirms the significant differences between the types. The highest homogeneity (xmax=77.45; xmax-1=14.98; Cc=73.5%) was observed in type 1 sand, while type 4 sand shows the minimum degree of homogeneity (xmax=47.30; xmax-1=42.28; Cc=8.7%). According to the test results, the maximum values of both densities in type 2 are: ρd=1.519 g/cm2, ρw=1.951 g/cm2, and the minimum values of both densities in type 4 are: ρd=1.438 g/cm2, ρw=1.894 g/cm2. The maximum natural moisture content in Type 1 samples is vn=9.5%, while the minimum values are 7.6% and 7.2% (Type 2 and 4). The obtained private density values have a high degree of convergence because the coefficients of variation have very low values: for Type 1 sands are 0.1-0.3%; for Type 2 sands are 0.7-0.8%; for Type 3 sands are 0.5-0.7%; for Type 4 sands are 0.4-0.6% (variation of private density values of dry and wet sands, respectively). Analysis of the results of tests on the shrinkage of samples showed that the maximum shrinkage is observed for sands of type 1 equal to 15.63%, while the minimum shrinkage is characteristic of samples of type 3 and 4 (11.25% and 11.88%). Taking into account the suitability of sand for the production of foam concrete, the most preferable is Type 1 sand mined in the Eltok building sand deposit.

Evaluation of incorporation of granite waste and SnO2-NPs into coating mortar for gamma-ray shielding

This study explores the use of waste granite and tin oxide nanoparticles (SnO2 NPs) as replacements for sand in mortar composites containing Ordinary Portland Cement (OPC), Hydrated Lime (HL), and Quarry Sand (QS). Scanning electron microscopy (SEM) imaging revealed an increase in particle distribution between voids in the control mortar, enhancing photon absorption. The density of the prepared mortar samples exhibited a notable increment, with a 2.12–2.30 g/cm3 increase through the inclusion of SnO2-NPs. Additionally, the Phy-X software was employed to experimentally measure and theoretically calculate the linear attenuation coefficient (LAC), demonstrating a high degree of agreement between the two values. The LAC values were found to increase with the replacement ratio of granite waste and SnO2 nanoparticles, demonstrating the effectiveness of these materials as radiation shielding agents. This study investigates the effect of substituting waste granite and SnO2 nanoparticles for sand in mortars, resulting in an increase in LAC levels, indicating potential for improved radiation shielding capabilities, although the degree of change in LAC may be energy-dependent. The half value results (HVL) results demonstrated a significant decrease in required material thickness for radiation shielding applications with numerical values of 1.153, 0.734, 0.456, 0.351, and 0.261 cm for the control, Mor-1, Mor-2, Mor-3, and Mor-4 samples, respectively, at an energy of 0.06 MeV.

The Comminution of Chert Gravel by Microwave Irradiation

Chert, a by-product rock of sand quarrying, has historically posed economic challenges for aggregate production, resulting in significant “waste” accumulation in quarries. Our study investigates the effect of microwave irradiation on the mechanical properties of chert gravel, a mineralogically homogenous material composed of fine quartz grains. The results, which demonstrate that increased irradiation time leads to a substantial decrease in chert gravel strength (by a factor of 4–6 for 2.5 min of irradiation), underscore the potential impact of this research on comminution processes. With quenching altering the fractional content of the samples after the crushing test, reducing the Gravel-to-Sand ratio, this study is driven by the promising potential of crushed chert gravel as a pivotal aggregate within the concrete and asphalt industries, offering a practical solution to their material needs. The urgent need to rehabilitate previously utilized quarry areas, offering an environmentally beneficial solution for which we all should be responsible, motivated the present study.

Mammal-bearing Pleistocene deposits, Vranić, southwestern Pannonian Basin System

Vranić site is a sand quarry that is located on the southern foothills of Papuk Mountain. From bottom to top of the succession, three sedimentary units have been recognized as: Unit 1 containing massive sand with scattered gravel-sized clasts, marl cobbles and boulders, and abundant marine mammal and fish fossils; Unit 2 consisting of sand intercalated with silt, clay and gravel, which may be horizontally bedded; and Unit 3, which is an erosionally-based lenticular matrix to clast-supported structureless gravel. The basal part of Unit 1 shows numerous reworked skeletal remains of Miocene marine mammals. Cosmogenic radionuclides constrain the age of burial of Unit 1 to 895 ± 211 ka, while the source area of Unit 1 had a quick denudation.The massive sands deposited on the slopes of Papuk Mountain were vulnerable to erosion due to the absence of clay. Heavy rainfall or water from snow melting created flash floods that infiltrated the sands, thereby causing slope destabilization and deformation. This process led to slumps that were transformed into a sandy debris flow. This sediment was probably deposited during the interglacial marine isotope age (MIS) 21 period when the scarce vegetation and a warmer climate favored the melting of permafrost ice and consequently triggered slope movements during MIS 22. The reworked skeletal material sampled at the Vranić site comprises fossilized fish along with mammal bones and teeth. Thus, the Vranić site represents an important site for cetacean fossil remains and serves as an important data source for marine life in the Central Paratethys.

Review on Investigating Soil Stabilized Mud Blocks with Combined C&D Waste

Buildings built by ancient civilizations like the Mesopotamians and Egyptians were made of clay and other materials, and the use of stabilized soil for construction dates to those times. On the other hand, the scientific underpinnings of soil stabilization were not established until the early 1900s. In comparison to conventional building materials, the use of stabilized soil-based construction materials, such as soil stabilized mud blocks, can offer several advantages, such as improved strength and durability, less of an adverse effect on the environment, and lower costs. The world is facing an issue that calls for the disposal of inorganic solid waste to be addressed right away. This solid waste that is produced when old buildings are demolished is frequently classified as industrial waste or C&D waste. In India alone, enormous amounts of waste are produced, very little of which is recycled. When modifying the properties of stabilized soil, this C&D waste can be used in place of soil or quarry sand. This work explores the use of a stabilizing agent in conjunction with combined C&D waste for soil sampling. The studies use combined C&D waste and soil stabilized mud blocks to test the hollow blocks' water absorption capacity and strength for various replacements. The materials needed for the study came from nearby structures that had been demolished. Using mortar, cylindrical samples for 32 different ratios of mixed construction and demolition waste with a 9% cement content were cast for various compositions. To determine whether the stabilized samples were suitable for use in construction, tests were conducted on their compressive strength and water absorption properties. Based on the least compressive values found in cylindrical samples, the C&D waste was used in ratios ranging from 0% to 100% in place of soil. Mud blocks stabilized by soil were poured and examined for durability, strength, and mechanical qualities. In this study, an effort was made to use C&D waste—that is, brick and concrete waste—in varying amounts to create cylindrical samples that could be used to create concrete and stabilized mud blocks. In order to create cylindrical samples, different ratios of brick waste, concrete waste, and brick-concrete waste were used for 23 mix proportions. Cylindrical samples were manufactured using a cement content of 9 and 12%. These samples' mechanical and physical characteristics, such as their compressive strength, water absorption capacity, and initial rate of absorption, were investigated.

Experimental investigation and evaluation of the compactness and moisture damage of asphalt mixes incorporating dune and river sand

Road construction is mainly based on the use of raw materials that must be in compliance with the standards, thus ensuring the quality and durability of the road. The use of dune sand and river sand in road geotechnics is an interesting subject. Both types of sand can be used in road construction and maintenance for a variety of applications. Dune sand is often appreciated for its uniform grain size and drainage capacity, while river sand can offer good mechanical strength. The majority of common bituminous mixes contain fillers made of quarry sand, whose amounts are difficult to regulate because of the variety of rock deposits and the conditions under which they are manufactured. In this paper, the compactness and moisture damage of asphalt mixes with two sand types, River sand (RS) with (0/4) size was sourced from the valley in the province of Medea (Algeria) and Dune Sand (DS) with a particle size of (0/0.5) was obtained from a dune in the Algerian province of Djelfa, were examined. Furthermore, a 100% replacement rate by weight of Crushed Sand (CS) with (0/3) mm size was used (quarry sand). The investigation employed a comprehensive approach, utilizing Marshall and gyratory shear compaction tests to assess compactness, while moisture damage was evaluated through rigorous water resistance testing and compressive strength methodology. The results of the study reveal a notable disparity in the mechanical performance of asphalt mixtures containing dune and river sand, showcasing diminished compactness and heightened susceptibility to moisture-induced damage when compared to alternative mix formulations. These findings underscore the critical role of sand type selection in asphalt mix design, emphasizing the need for careful consideration to optimize performance and durability.

The Effect of Fineness Modulus of Fine Aggregate on Concrete Compressive Strength

Concrete is the major material used for most civil engineering constructions like buildings, bridges, culvert, rigid road pavement, dam spillway and so on. Concrete is made from a mixture of cement, fine aggregate (sand), coarse aggregate (granite or gravel), and water. The fineness modulus is one of the physical properties of fine aggregates (sand). The Fineness Modulus (FM) of fine aggregates (sand) is obtained from the grading size distribution test as summation of percentage cumulative retained by series of sieves and divided the sum by 100. The fineness modulus of sand differs for each sand quarry. The purpose of this research is to analyze the effect of fineness modulus of fine aggregate (sand) from three different sand quarries on concrete compressive strength. The sand for the study were taken from three quarries (Ayegun, Akufo and Awotan) in Ibadan, Oyo state, Nigeria. The specimens of concrete used in the form of the cube measuring 150x150x150 mm amounted to 36 specimens. The compressive strength of concrete (fc’) targeted is 21 N/mm2 with W/C ratio 0.5. Concrete mix ratio of 1:2:4 was batched by weight. The results showed that the fineness modulus of sand strongly influence the compressive strength of concrete. The classification of sand type is differentiated based on the results of fineness modulus test on each sand sample. Sand fineness modulus (FM) of Ayegun quarry is 2.64 called medium sand (zone 2). Sand fineness modulus of Akufo quarry is 2.35 called mild sand (zone 3), and, sand fineness modulus of Awotan quarry is 1.57 called fine sand (zone 4). Concrete compressive strength values of Ayegun, Akufo and Awotan quarries sand were 21.3 N/mm2, 22.4 N/mm2, and 20.5 N/mm2, respectively. The value of sand fineness modulus does not affect the increase in the concrete compressive strength. The best classification of fine aggregate to increase concrete compressive strength is mild sand (Akufo quarry) and all the sand samples meet the planned concrete compressive strength of 21 N/mm2.

Stabilization and Recycling of Sand in Pedestrian Walkways

The production of construction and demolition waste (CDW) in urban areas is growing rapidly. While the storage and disposal of CDW waste is costly, its recovery can help to conserve natural resources. This study investigates the characteristics of recycled sand obtained from the processing of CDW waste and the possibility of its reuse for pedestrian pathways. Physico-chemical and mineralogical characteristics of the recycled sand were investigated for its reuse. The percentage of fine particles in sand (below 0.63 μm) is 2.8%. The grain size of sand fulfills the particle size requirement of French standards. The methylene blue value of sand is 0.05 g/100 g. The GTR classification of recycled sand is D2 which is insensitive to water and suitable for road applications. A mineralogical analysis of soil shows that quartz, albite and microcline are important minerals in recycled sand. XRF analysis shows that CaO and SiO2 are major oxides in the recycled sand. The characterization of sand was followed by a manufacturing of cylindrical specimens of sand to observe the compressive strength. Samples were compacted with dynamic compaction by applying the Proctor normal energy of 600 kN·m/m3. The compressive strength testing of specimens shows that non-stabilized sand samples have compressive strength around 0.1 MPa which is considerably lower for its reuse in pedestrian pathways and road applications. Due to the low bearing capacity of sand, recycled sand was stabilized with the addition of binders such as Rolac (hydraulic binder), ground-granulated blast furnace slag (GGBS) and ECOSOIL® (slag mixes) with different percentages of the binder ranging from 0 to 7% for the optimization of the binder and for economic efficiency. The compressive strength of sand samples increases with the increasing percentage of the binder. The increase in strength is more important with a higher percentage of binders (5%, 6% and 7%). At a 7% binder addition, specimens with Rolac, GGBS and ECOSOIL binders show the compressive strength of 1.2 MPa, 0.5 MPa and 0.5 MPa. At a 7% Rolac addition, specimens have a compressive strength higher than 1 MPa and meet the strength requirement for soil reuse in the foundation and subbase layers of roads with low traffic. The experimental work shows that recycled sand can replace conventional quarry sand for road applications and pathways with the addition of a local binder, which is an eco-friendly and economical practice.

Structural Shifts in the Soil Prokaryotic Communities Marking the Podzol-Forming Process on Sand Dumps

This work describes the microbial community structure of the continuously revegetated chronosequence of a former sand quarry, which demonstrates a unique example of nearly complete soil restoration in less than 100 years. Samples were collected at five time points (0, 3, 30, 70 years and mature soil) from the entire set of soil horizons, revealing the history of pedogenesis. Real-time PCR was applied to quantitatively describe the bacterial and archaeal communities. High-throughput sequencing of the bacterial and archaeal V4 variable region of the 16S rRNA gene was used to identify abundant microbial taxa. A beta-diversity analysis revealed that the prokaryotic community structure responded strongly to the processes of organic matter accumulation and the corresponding evolution of the soil into discrete horizons. Changes in soil microbiota in the course of soil profile evolution revealed three groups of prokaryotes, which tended to accumulate in the specific soil horizons and might be associated with the certain soil-forming processes, including plant roots growth. This research showed the heuristic potential of soil horizon profiling in microbiological studies as opposed to the formal depth-dependent separation of the soil layers. The results allowed us to trace the relationship between the structure of the soil prokaryotic community and the peculiarities of the evolution of the podzolic soil profile as well as to identify the microbial indicators and drivers of primary pedogenesis.

Indicators to quantify biodiversity gains for compensation and mineland rehabilitation in the Eastern Amazon.

To connect the protection of natural resources to economic development, environmental rehabilitation is a promising way to repair and compensate for impacts on biodiversity and ecosystem services. Here, we aimed to compare and select potential indicators for the success of different rehabilitating ecosystems to quantify gains in biodiversity and ecosystem services within the Impact Mitigation Hierarchy. We sampled nine environmental variables along rehabilitation chronosequences from rehabilitating (i) iron mining waste piles, (ii) sand quarries, and (iii) compensation areas in the Carajás National Forest. From that, we computed the rehabilitation status, i.e., the proportion of environmental enhancements compared to the overall rehabilitation trajectory, and statistically validated the indicators that best described the status. With a mean rehabilitation status for the oldest rehabilitation stages from waste piles, sand quarries, and compensation areas of 52, 71, and 74%, respectively, we confirmed that rehabilitation activities were able to generate considerable gains in biodiversity. In all the cases, the Shannon diversity, phylogenetic diversity and Leaf Area Index performed better than did the other indices, encouraging the increased use of these indices for upscale monitoring activities. Consistent indicators across distinct projects highlight the importance of maximizing tree diversity and canopy closure in rehabilitation projects to increase biodiversity gains within Impact Mitigation Hierarchy.

Study and valorization of a new bituminous concrete based on natural dune sand for hot and arid environments

The trans-desert road network is exposed to enormous degradation of asphalt concrete pavements due to the high temperatures of these arid regions, which considerably accelerate asphalt ageing. Common bituminous mixes generally use quarry sand fillers, the proportions of which are poorly controlled due to the diversity of rock deposits and their manufacturing conditions. This article responds to this problem by proposing dune sand as a source of filler by grinding it and then introducing it into pure bitumen to obtain the bitumen-filler mix. In this paper, two types of analysis were carried out, one thermal and the other mechanical to study the influence of the substitution of quarry sand filler by dune sand filler in asphalt concrete. In the thermal analysis, the study evaluates the stiffening power (?TBA) of three types of fillers incorporated into a pure bitumen, namely quarry sand, dune sand and standardized filler. The results of these analyses reveal that at a normative percentage of 57% filler with 43% pure bitumen, the stiffening power (?TBA) of dune sand filler and normalized filler comply with established standards (between 8 and 16°C), unlike quarry sand filler, which does not meet standards. The mechanical analysis carried out on quarry sand filler and dune sand filler revealed an improvement in mechanical performance when dune sand filler was used, with MARSHALL stability values indicating an average increase from 3.9 to 4.9, and better resistance to water with a greater than 99% ratio for the DURIEZ test well above the 75% threshold. These results offer the potential to optimize bituminous mixes by incorporating dune sand fillers, thereby enabling Saharan roads to be built more quickly, at lower cost and, above all, to extend their lifespan, making a positive contribution to the development of road infrastructure in hot, arid environments.

Effects of Polypropylene and Date Palm Fiber Reinforcements on High Performance Concrete at Elevated Temperatures and Their Impact on Spalling Phenomena

Concrete, a widely utilized construction material, faces challenges related to thermal instability when exposed to fire-induced temperature variations. To address the issue of explosive spalling, common concerns in concrete, polypropylene fibers, recommended by Eurocode 2, are added to the mix. This study aimed to evaluate alterations in physical and mechanical properties of high-performance concrete incorporating various fibers, including polypropylene and palm tree waste as an eco-friendly alternative to conventional fibers. The incorporation of palm fibers aligns with the promotion of local materials for their potential affordability due to local abundance. The assessment involved four high-performance concrete formulations tested under high-temperature conditions: SF (silica fume without fibers), SFPP (silica fume with polypropylene fibers), SFDF (date palm fibers with silica fume), and SFPPQS (polypropylene fibers with quarry sand, siliceous sand, and silica fume). Destructive and non-destructive evaluations encompassed compressive strength, flexural strength, ultrasonic pulse velocity, and mass loss. Experimental tests were conducted at room temperature (20°C) and elevated temperatures (250°C, 450°C, and 650°C). Results revealed a decline in both compressive and flexural strength for samples exposed to temperatures above 450°C. Notably, the inclusion of date palm fibers mitigated mass losses while exhibiting a lower compressive strength.

Comparative Study of Mortars Made with Sands of Different Geological Origin

The present work is a comparative study of sand mortars from various geological origins to highlight their influence on mortar qualities. Five different sands and the cement CEM II/B–P 42.5R were used to produce mortars with similar water/cement ratios (W/C). These are the “Sanaga” sand from the Sanaga River, the “Wouri” sand from the Wouri River, the Nyambaka basalt sand, the Meiganga granite sand, and the Leboudi gneiss sand. The physical, chemical, and mineralogical features of these sands were used to characterize and classify them. They were then used to formulate mortars, which were analyzed and compared. According to the results of the mortar setting time tests, the initial setting time ranges from 195 minutes for Sanaga sand mortar (MS04) to 210 minutes for gneiss sand mortar (MGN03), passing Wouri sand mortar (MW05) with 200 minutes, basalt sand mortar (MB01) with 198 minutes, and granite sand mortar (MGR02) with 196 minutes. The final setting time ranged from 496 minutes (MGR02) to 510 minutes (MGN03), with an average of 300 minutes added to the initial setting time. The flexural strength tests of the mortars reveal that crushed sands outperform alluvial sands. They range from 1.64 to 2.18 MPa after 2 days, 3 to 3.90 MPa after 7 days, and 7 to 14.84 MPa after 28 days. The results of the compressive strength tests show that quarry sand mortars have greater average compressive strengths than alluvial sand mortars, with basalt sand providing the greatest performance. These strengths range from 6.35 to 10.83 MPa after 2 days, 7.55 to 18.96 MPa after 7 days, and 22.81 to 34.58 MPa after 28 days, with the MB01 being the best sand. These findings reveal that the geological origin of sands, which specifies certain of their physicochemical and mineralogical attributes, has an impact on the properties of mortars. This impact is also influenced by granulometry and organic matter concentration.