Industrial Sand Research Articles

A “natural sand plant” at the shelf edge in the low-energy Gulf of Lions, western Mediterranean Sea

Thick sand deposits at the edge of continental shelves, sometimes covered with large bedforms, are generally considered as relict features inherited from periods of low sea level, but alternative interpretations are possible, even in zones where modern oceanic processes are moderate. Detailed investigations in the western Gulf of Lions (western Mediterranean Sea) reveal the presence of remains of Marine Isotope Stage 4 (MIS 4) and MIS 2 shelf-edge deltas at the head of canyons. The sands were then “cannibalized” by strong rising sea-level currents, forming a 20-km-long, strike-oriented sand body covered by dunes. Presently, the migration of dunes is maintained by strong storm-driven currents. The seasonal reversal of circulation is at the origin of inversion of dune morphology, thus the sand body mimics a tidal sand bank with clockwise circulation of bedforms. In the long term, dunes migrate southward with a negative angle of climb, eroding into the underlying shelf-edge deltas. Acoustic Doppler current profiles and numerical simulations indicate that the sediment is sorted, once in suspension, and is flushed to the deep sea while sand bedload contributes to bedform migration. This relative enrichment of sand without external supply is referred to as a “natural sand plant,” by analogy with industrial sand plants where sand is washed and sieved. It forms a discontinuous sand belt, 5−20 m thick, more than 110 km along-strike, connecting multiple shelf-edge deltas. The geological importance of recognizing this recycling mechanism is indicated by the preservation of similarly large buried dunes formed during the deglaciation leading to interglacial MIS 7 at ca. 240 ka (Termination III).

From waste to an added-value commodity: challenges in valorization opportunity of tin-residual sand for silica-based industry

Abstract Extensive tin mining activities produce sand piles with high silica, leaving vast environmental and economic responsibilities. The circular economy implementation can address these problems by valorizing quartz sand as industrial sand. Therefore, the study assesses the quartz sand left over from tin mining and processing activities on Bangka Island to become a valuable product within the CPQvA Framework consisting of classification (C), potential utilization (P), quantity and viability (Qv), and application (A). The criteria comprise 12 weighted questions to define the criticality indices categorized as easy, moderate, and difficult. With complex purification technology, quartz sand can be used as silica sand for ceramics, foundry mould, refractory bricks, glass, and solar cells. The quantity is large and feasible for a factory scale with expensive investment and operational costs. The product performance shows good quality from a technical aspect. Due to impurities content and its complex purification technology, the valorization of quartz sand produces a difficult criticality index for the solar cells, a moderate criticality index for the glass and ceramics industry, and an easy criticality index for the glaze, refractory brick, and foundry mold industries. Therefore, proven and efficient purification technology is crucial for further research.

Evaluation of garnet phenocrysts in volcanic rocks (Görece/İzmir – Western Türkiye) for their usability as a semi-precious gemstone by multi-analytical methods

Garnets are observed as phenocrysts in blocky rhyolites of Cumaovası Volcanites and are reddish-blackish in color, show vitreous luster, and have dodecahedron forms varying between 0.5 and 2.0 cm in size. In optical microscope investigations, they exhibit fractured structures and contain quartz, hematite, chlorite, and acicular rutile inclusions. Garnet phenocrysts are highly consistent with spessartine-type garnet end members in the Raman spectrum. This result is supported by the mineral chemistry results determined as spessartine (Sps)0.50–0.52 almandine (Alm)0.47–0.48 grossular (Grs)0.01–0.02. In the chondrite, primitive mantle, and Mid-Oceanic Ridge Basalt normalized multi element variation diagrams, garnet phenocrysts show enrichment in all elements (except Sr, K, P, and Ti). In contrast, in the upper continental crust normalized multi element variation diagram, garnet phenocrysts show depletion in large ion lithophile elements (Rb, Ba, K, and Sr) relative to high field strength elements. They exhibit slight enrichment in light rare earth elements ((La/Sm)N = 0.11–1.07) relative to heavy rare earth elements ((Sm/Yb)N=0.78–0.97). Furthermore, garnet phenocrysts have significant negative europium (Eu) ((Eu/Eu*)N = 0.01–0.02) and mildly positive cerium ((Ce/Ce*)N = 2.43–13.77) anomalies indicating hot and reduced magma conditions. The Y/Ho ratios have ranged from 18.9 to 20.3 and are close to the chondrite value. The zircon saturation temperatures (TZr) of the garnet’s host rock was determined to be 756 °C. As a result of mineralogical, geochemical and gemological studies, it was concluded that Görece garnet phenocrysts have glassy luster and semi-transparent dodecahedral crystal shapes, so they can be classified as semi-precious gemstones. In addition, the rare earth element content of the garnet phenocrysts is similar to that of industrial garnet sands and it is thought that they may have potential.

M100 concrete probing on quinary cementitious matrix incorporated with industrial ferrochrome slag sand

The potential exploration of micro (10−6) and nano (10−9) sized binders and Ferrochrome slag sand (FSS) is supplanted and discussed in the M100 concrete. Supplementary Cementitious Materials (SCM) and FSS are supplanted in concrete to sustain and minimize the exploitation of resources. The clinker products are diminished by replacing SCM like Metakaolin (MK) of 8, 10, and 12% and Nanosilica (NS) of 0.5, 1 and 1.5%. Besides, the FSS (10, 20, 30, 40, 50, and 100%) is incorporated in the place of crushed sand (Csand). The in-depth material characterization demonstrates the shape, micro texture, and elemental analysis. The optimum mix (F4) has a compressive strength of 126.08 N/mm2 at 28 days. The densely hydrated cluster (CSH(H&L)) in the F4 mix are an intellectual cause of strength gain. The microstructure with Hadley grain (Peeling bark) in the F10 mix is a root for the strength degradation. The MgO in slag escalates the strength at 365 days. The Packing action of SCM and FSS are schematized. The TGA plot of the F4 mix has a significant (−9.34%) silicate hydrate peak than referral concrete (RC). The Global warming potential (GWP) of the F4 mix saves 12.96% emission of CO2 than RC.

Optimizing Coal Ash as a Sustainable Substitute of Cement and Aggregate in Structural Concrete

The manufacture of concrete for constructing the structures like highways, bridges, and buildings requires large amounts of cement and aggregates. This high concrete production depletes natural resources like sand and gravel for the construction industry. It also negatively impacts the environment due to cement usage. This study looked at using waste materials like coal bottom ash (CBA) and fly ash (FA) in concrete as substitutes for some of the typical aggregates and cement. The goal was to reduce the environmental impact and preserve natural resources. The study made concrete with regular Portland cement, sand, 10mm coarse aggregate, locally available CBA, and FA. 15% fly ash was selected as an optimal level from initial testing. The CBA was used to replace 0-35% of the fine aggregate sand. Test cubes and cylinders were made with different mixes. Compressive strength, tensile strength, carbonation, and sulfate attack tests were done after curing. Results showed 25% CBA improved the concrete’s mechanical performance. The compressive and tensile strengths increased but not above conventional concrete. This is because CBA needs more moisture for full hydration over longer curing times. Also, the concrete’s durability improved in terms of resistance to carbonation and sulfate attack.

ULTRA-HIGH PERFORMANCE CONCRETES WITH PHENOLIC FOUNDRY SAND: MECHANICAL AND MICROSTRUCTURAL EVALUATION

In this investigation, the properties of ultra-high-performance concretes (UHPC) produced with different binders and aggregates were analyzed. Ternary and quaternary mixtures were tested, including structural white Portland cement (WPC), silica fume (SF), hydrated lime (HL), rice husk ash (RHA), fly ash (FA), and limestone filler (LF), in combination with industrial sand (IS) and discarded foundry phenolic sand (DFPS).
 The mixtures underwent two types of curing: moist curing until the testing age and moist combined with thermal curing. The concretes were evaluated for compressive strength and microstructure using thermogravimetric analysis (TG/DTG) and Fourier transform infrared spectroscopy (FTIR) techniques.
 The results showed that all mixtures achieved the desired levels of strength for UHPC (150 MPa). Up to 28 days, the mixtures with RHA exhibited higher strength compared to those with FA, regardless of the curing type. However, at 91 days, the mixtures with FA and thermal curing were more resistant than the mixtures with RHA. Among the quaternary mixtures, at 7 days, the strengths of the mixtures were equivalent, indicating that FA did not react at earlier ages.

Processing of Alluvial Deposit Sands with a High Content of Copper and Nickel Using Combined Enrichment Technology

The aim of the present research was to examine the process of bioleaching and the application of a combined process for the recovery of copper and nickel from industrial sand deposits. The investigated sample of sands finer than 0.1 mm in size contained 0.32% Ni and 0.22% Cu. Industrial sands were processed by bioleaching in flasks on a thermostatically controlled shaker. In addition, sand roasting experiments were carried out with ammonium sulfate. An attempt was also made to use a combined process, including low-temperature roasting of the sands mixed with ammonium sulfate, water-leaching of the roasted mixture, and subsequent biological after-leaching of the residue. In the process of roasting the industrial sands in a mixture including ammonium sulfate at a temperature of 400 °C, more than 70% of the non-ferrous metals were recovered. We examined the possibility of recovering non-ferrous metals using a combined process including low-temperature roasting of industrial sands and the additional recovery of non-ferrous metals by bioleaching using the Acidithiobacillus ferrivorans bacterial strain, which was found to increase the recovery of non-ferrous metals to up to 90%.

Spatial distribution and reserve estimation of sand and gravel deposits using geostatistical methods in west Basrah, southern Iraq

Sand and gravel are among the most common natural materials. They are generally used as a raw material in concrete, road construction, mixing with asphalt and filling material, among other uses. Sand and gravel deposits are widespread within the southern and central regions of Iraq. Among these deposits are the alluvial sand and gravel that form the upper part of the Dibdibba Formation in the Al-Rafiya, Al-Tuba, Chwaibda and Safwan blocks in west Basrah, southern Iraq. In this research, grain size distribution for channel samples collected from each block was determined. Thickness of overburden and industrial beds was measured and the stripping ratio (SR) was calculated. Geostatistical interpolation approaches including inverse distance weighting (IDW) and ordinary kriging (OK) were utilised to predict the spatial distribution of sand and gravel deposits and their reserves from borehole data. Data validation using the mean error (ME) and root-mean-square error (RMSE) were applied. The deposits can be characterised as gravelly sand (gS) in the Al-Tuba, Al-Rafiya and Chwaibda blocks, while it is a sandy gravel (sG) in the Safwan block. The overburden gypcrete beds varied between 1 and 3 ​m thick, while the industrial sand and gravel beds which appear as planar and sometimes lenticular deposits ranging between 3 and 8 ​m thick. The SR is generally low, considering the easily removed lightweight material of the overburden bed and the easily extractable fairly flat and near-surface friable sand and gravel deposits. Reserves are estimated as 376.63 Million m3 and 385.97 Million m3 using the IDW and OK approaches, respectively. Based on the least error values of ME and RMSE, we conclude that the OK method is the more accurate spatial interpolation approach for sand and gravel reserve estimation in all blocks compared to the IDW method.

Valorization of waste foundry sand aggregates in hot-mix asphalt

Metal smelting generates a significant volume of industrial solid waste foundry sand (WFS). Although several standards and studies have established practices and requirements for its use, a large portion of the disposed WFS goes to industrial landfills. This study aims to evaluate the value of WFS as an aggregate in hot-mix asphalt mixtures (HMA) using systematic criteria for classification, potentialities, waste generated and applicability. To this end, molding sand (MS) and fine dust of exhaustion (FDE) were characterized, to identify their potential for application as aggregates in asphalt mass. Different contents of MS, FDE, and Blend (BL) were studied according to the normative granulometric ranges of aggregates for HMA. Samples were obtained via the Marshall method to verify important properties for the asphalt mix. Ecotoxicity tests were conducted. The results showed that a composition containing 10 wt% of BL presented an air void volume of 3.3%, a stability of 658 kgf, creep of 2.5 mm, and an indirect tensile strength of 0.93 MPa. From a technical and environmental perspective, a 10 wt% BL content was suitable for recovery into HMA. Lower amounts BL yielded results outside the normative limits. WFS can be recovered and applied as a raw material in HMA.

Solvent Extraction for Separation of Indonesian Oil Sands.

Based on the examination of the basic properties, the solvent extraction process (SEP) was applied with high efficiency in the extraction of bitumen from Indonesian oil sands. To separate the oil sands, different organic solvents were first screened, and the extraction effects were analyzed to select a suitable solvent. Then, the effects of operating conditions on the extraction rate of bitumen were investigated. Finally, the compositions and structures of the bitumen obtained under suitable conditions were analyzed. The results showed that the Indonesian oil sands were oil-wet oil sands with a bitumen content of 24.93%, containing a large number of asphaltenes and resins with high polarity and complex structures. The separation performance was affected by different organic solvents and operating conditions. It was shown that the closer the structure and polarity of the selected solvent is to the solute, the better the extraction effect. The extraction rate of bitumen reached 18.55% when toluene was used as the extraction solvent under the operating conditions of V (solvent):m (oil sands) 3:1, temperature 40 °C, stirring velocity 300 r/min, time 30 min. The method could also be applied to the separation of other oil-wet oil sands. The compositions and structures of bitumen can guide the separation and comprehensive use of industrial oil sands.

Road Marking Glass Microspheres Fabricated from Rice Husk Ash

In this work, it is reported a comparison between solid microspheres produced from glass having conventional industrial sand (IS) and glasses made with rice husk ashes (RHA) as a source of silica. The same composition was used to fabricate both glasses. The focused was the production of glass microspheres for road horizontal marking, which would attend the type classification called Premix. The microspheres were obtained by the horizontal flame method. The results showed that characteristics such as production yield, morphology, granulometry and, mainly, retroreflectivity measurements are not altered when rice husk ash is present in the glass composition, showing that this can be a sustainable alternative material for this important application.

Reality Check on a Purported Global Sand Shortage: Sensationalism Extrapolated from Isolated Occurrences to Global Phenomena

Since 2013, there has been a proliferation of opinion pieces pertaining to a global shortage of sand.  Because of the current volume of such articles, the situation is taken as fact and industries like fiberglass insulation manufacturers are being criticized for exploiting the earth’s dwindling supply of sand.  Research has shown that these are sensationalized headlines (rather than actual scientific reporting) and they are proliferating because they benefit author of opinion and social media content.  The genesis of the popular sand shortage story can be traced to a 2013 documentary, Sand Wars, and an unintentional foundational basis for the issue derived from a short discussion on international trading and island building in the book, Sand, The Never-Ending Story.  Extensive research conducted for this article confirms that there is no general, worldwide shortage of sand; instead, there are only isolated shortages in some areas outside the US.  Most importantly, the sand that is the subject of the purported global sand shortage stories is not the same sand (industrial sand) that is used by the fiberglass industry.  Finally, that industry’s use of industrial sand has declined over time as it increases the use of recycled glass cullet as a sand substitute.

Численное моделирование самосогласованной динамики поверхностных вод, влекомых и взвешенных наносов: II. Исследование поперечных деформаций русла и перераспределения расходов воды по рукавам р. Волги при промышленной добыче песка

The dynamics of water levels, transverse channel deformations, and redistribution of water discharges along the branches of the Volga River, both during planned industrial sand mining and during extreme transformation of the bottom topography in the area of the quarry, have been studied. A real quarry of non-metallic building materials was considered, located at the mouth of the Volozhka Partridge of the Volga — Akhtuba floodplain (VAF) in the section 2549–2550 km of the Volga River. Mathematical modeling of the joint dynamics of shallow waters, traction and suspended sediments is carried out, which takes into account the nonlinear dynamics of the liquid and bottom deformations. For the numerical solution of the Saint-Venant and Exner equations, the CSPH-TVD method was used, the parallel CUDA algorithm of which is adapted for highperformance computing on supercomputers with graphics coprocessors (GPUs). It is shown that the conditions of quarry development, both during planned mining and under extreme bottom deformation, do not significantly affect the structure of channel flows along shipping routes.

The impact of river sand mining on remobilization of lead and cadmium in sediments – A case study of the Jialing River

Due to the fast pace of urbanization worldwide, industrial sand mining activities have imposed great pressure on the environment, and consequently, these activities have led to serious environmental problems in aquatic ecosystems. However, the current understanding of the effect of sand mining on heavy metal remobilization in river sediments remains incomplete. The present study employed sediment quality guidelines (SQGs) and the sequential extraction (SE) and diffusive gradients in thin films (DGT) techniques to comprehensively investigate the effect of sand mining on the remobilization process of heavy metals in the aquatic system of the Jialing River. The SQGs results indicated that stations (S1 to S4) with sand mining disturbance exhibited Pb and Cd accumulation in surface sediments. Both Ctotal-Pb (61.78–122.04 mg·kg−1) and Ctotal-Cd (0.85–3.96 mg·kg−1) were higher than CSQGI (60 mg·kg−1 for Pb and 0.5 mg·kg−1 for Cd) and TEC (35.8 mg·kg−1 for Pb and 0.99 mg·kg−1 for Cd) limitation in most of sand mining stations. Pb and Cd were mainly bounded in the acid-soluble/exchangeable fraction (F1) and oxidizable fraction (F3) of the surface sediments. At the four stations with sand mining disturbance, about 5–10 folds of DGT-labile Pb and Cd were released in deep sediments (−9 to −12 cm), and Pb and Cd exhibited a transport trend from the sediments into the overlying water, while the above phenomenon was not observed at the two stations without sand mining activities. Correlation analysis revealed that DGT-labile Pb and Cd were suitably correlated with the F1 and F3 fractions, indicating that the acid-soluble/exchangeable and oxidizable fractions were the main sources leading to Pb and Cd remobilization in the sediments. A potential mechanism explanation may be that (1) intense sediment stirring could result in remobilization of the weakly bound fraction, which is related to the contribution of the F1 fraction, and (2) Cd/Pb experienced a corelease process with sulfur due to O2 introduction (elevation of the dissolved oxygen level) attributed to sediment evacuation, which is related to the contribution of the F3 fraction. The above results suggested that sand mining in the Jialing River should be paid high attention to prevent heavy metal pollution in aquatic ecosystem.

Use of Industrial Silica Sand as a Fine Aggregate in Concrete—An Explorative Study

Industrial silica sand is a by-product obtained from the industries like paint, paper, rubber etc. It has a similar property with river sand and& M sand. This study explores the effect of high content of silica sand as a partial replacement for fine aggregate for concrete making in construction purpose. In this present research four types of silica sand from two different industrial units (coarser silica sand (VC and TC) and finer silica sand (VF and TF)) were used. The physical classification and morphology observation of silica sand through scanning electron microscope (SEM), energy-dispersive X-ray (EDAX), X-ray fluorescence (XRF) is examined. Fresh and hardened concrete properties were performed for the six sand samples, with two grades (M20 and M30) of concrete. No new compositions or phases were identified in silica sand concrete. Both fine and coarse silica sands were finer than river sand and M sand, as evaluated from the physical classification. The workability of silica sand mix at a fresh state improves the concrete performance up to 40%. The mix, which contains 80% coarser silica sand (TC) with 20% river sand, attained the maximum compressive strength of 34.5 Mpa and tensile strength of 3.5 Mpa at 28 days, which was the greatest of all the mixes. The combination of silica sand and river sand or M sand showed the superior impact of the concrete over the discrete concrete. SEM images showed the well-developed hydrated products like calcium silicate hydrate (CSH), calcium hydroxide (CH) and ettringite in all concrete mixes. It was observed from the XRD pattern that all concrete mixes containing silica sand have a high peak of quartz (SiO2), and calcium silicate hydrate (CSH) exhibits the formation of hydration products in the concrete. Similar stretching and bending patterns of silica sand concrete relates the pattern of nominal sand concrete as observed from Fourier-transform infrared spectroscopy (FTIR).

Assessing the environmental risk and mobility of cobalt in sediment near nonferrous metal mines with risk assessment indexes and the diffusive gradients in thin films (DGT) technique

The Jialing River is the tributary of the Yangtze River with the largest drainage area. In recent years, the Jialing River has suffered a series of environmental problems, such as discharge of industrial effluent and sand mining activities, which have severely threatened the aquatic ecosystem of the river. In the present study, we employed risk assessment indexes, sequential extraction and the diffusive gradients in thin films (DGT) technique to assess environmental risks and study the remobilization of cobalt (Co) in sediments. The potential ecological risk index and risk assessment code results demonstrated that Co may pose a low environmental and ecological risk to the local aquatic environment. However, BCR sequential extraction showed that the sum of the F1, F2 and F3 fractions of Co still accounted for over 50% of the Co in the study areas, indicating that sediments may be a source of Co release. The DGT results showed an increasing trend for DGT-labile Co in deep sediments (−8 cm to −12 cm), and the calculated flux values ranged from 0.08 to 15.54 ng cm2·day−1, indicating that Co tends to transfer across the sediment-water interface at all sampling sites. Correlation analysis showed that F1–Co, F2–Co and F3–Co are the fractions readily captured by DGT and can be used for predicting Co remobilization in sediment. Sand mining activities contribute substantially to the release of Co from the F1 and F3 fractions as a result of strong stirring of sediments and introduction of oxygen into the sediments. The reductive dissolution of iron (Fe) and manganese (Mn) hydroxides or oxides causes the release of Co and Fe/Mn in the sediment, which leads to Co release from the reducible fraction. The above work suggests that sand mining in the Jialing River should be reasonably regulated to prohibit illegal sand mining activities.

Sustainable Concrete Columns with GGBS and Industrial Sand: A Comparative Study on Destructive and Nondestructive Tests on Damaged Columns Strengthened with GFRP Jacketing

This paper presents the experimental investigation of the load‐resisting characteristics of damaged columns repaired with glass reinforced polymer (GFRP) jacketing. The high‐strength columns were made with ground granulated blast furnace slag (GGBS) used at 15%, 25%, and 35% as a partial substitute for cement. Cube specimens of size 100 mm × 100 mm × 100 mm and columns of size 600 mm × 120 mm were cast to perform the study. Considering the practical difficulties in the construction field in obtaining river sand, industrial sand was used for making the specimens eco‐friendly. On completion of the prescribed curing period of 28 days, the cube specimens were subjected to a compression test to ensure the grade of the mix design, and the column specimens were subjected to axial loading and were tested in two categories, with and without wrapping of GFRP sheets’ split tensile strength. Compression tests on cubes and columns were done. The nondestructive test was also performed with the ultrasonic pulse velocity (UPV) method to check the dense nature of the concrete before and after wrapping with GFRP. On comparing the results, it was observed that it is possible to obtain a higher strength using industrial sand when supported with suitable admixtures and strengthening processes.

Surface and Groundwater Pollution as a Result of the Technogenic Impact

Old graves site of MSW (municipal solid waste) remain active as environmental source of pollution. The purpose of our research is the desire to study and improve an ecological aspect including the topic of surface and groundwater. Currently, the main waste disposal site for the Voronezh millionth city is a landfill located on the right bank of the Don near the rural area of the Devitsa in the Semilukskiy district of Voronezh region. This landfill of MSW began to be used in 2012. It is located closer to former used landfill closed in the same year. The former and now existing landfills were created on the site of previously worked quarries for the extraction of clay and sand for the construction industry. The landfill for receiving solid household waste (MSW – there was such a name in these years) was started to be used after excluding the significant comments of the place of former used Sredniy quarry mine in 1993. Waste collection began to work in 11.11.1993. The landfill accepted waste for disposal until 16.03.2012. Moreover, the situation with the storage of waste was considered as an emergency over the past few years. Since, according to the project, the landfill was overfilled by 30%! The main purpose of this article is to assess the intake of pollutants into groundwater from a closed landfill at the Sredniy mine in the Semiluksky district of the Voronezh Region and to determine their release into the Don River through the aquifer. The report of the monitoring activities of LLC Voronezhgeologiya will be used in the context of research. As a result, solutions of reducing the pollution impact on this area will be identified.

Impact of construction & demolition waste and slag sand on the properties of high strength self - compacting concrete

This Research mainly focuses to explore the characteristics of High Strength self-compacting concrete developed using industrial waste steel slag sand and construction demolition waste. The purpose of this study is to examine both rheological and hardened properties by incorporating steel slag sand and C&D waste as a substitute to M−Sand in different proportions along with comparison of the three sands in equal quantities. The test results exhibited good flow ability, passing and filling abilities for all the combinations adopted which satisfied the EFNARC Guidelines. The results showed that compression, split-tensile and flexural strength of High-performance self -compacting concrete has declination with higher percentages of steel slag sand and C&D Waste. The maximum declination was observed at complete replacements of slag sand with respect control mix. Utilization of adopted materials in equal proportions exhibited promising results compared to control concrete and this can be considered optimum.

Study on Triaxial Mechanical Properties and Micro Mechanism of Fly Ash Reinforced Cement Calcareous Sand

In order to study the mechanical properties and micro-mechanism of industrial waste fly ash-reinforced cement calcareous sand (FCS), the triaxial unconsolidated undrained (UU) test and scanning electron microscope tests (SEM) were carried out on it. The results of UU test show that the peak stress and energy dissipation of the FCS sample first increase and then decrease with the increase in fly ash content. Fly ash enhances the cement calcareous sand by increasing both the cohesion and internal friction angle, and adding 10% content of fly ash gives the largest values. The SEM test results shows that the hydration products of cement and fly ash filled the pores and cracks on the surface of the calcareous sand, which increased the compactness and structure of the FCS samples. The porosity of cement calcareous sand can be reduced from 27.6% to 12.8% by adding 10% fly ash. A brittleness evaluation index based on energy dissipation is proposed to quantitatively characterize the brittleness of FCS samples. The results show that when the content of fly ash is 5%, the brittleness of FCS samples is the lowest. This study shows that the mechanical properties of cement calcareous sand can be effectively enhanced by adding the appropriate amount of fly ash.