Natural River Research Articles

Hydrochemical Characteristics and Controlling Factors in Wudu River Basin of Guizhou Province

TheWudu River is a typical mining-type watershed in the karst mountainous area of western Guizhou Province. Based on the collection of the main stream, tributaries, spring water, and mine water samples in Wudu River Basin, the hydrochemical characteristics and control factors of Wudu River Basin were studied using Gibbs diagram, Piper diagram, and mathematical statistics analysis, and the solute contribution rate of different sources was calculated. The results revealed that the pH value of the water in the Wudu River Basin ranged from 7.87 to 8.52, with an average of 8.14. The TDS values ranged from 135 to 243 mg·L-1, with an average of 191.7 mg·L-1. The major cations in natural river and spring water were Ca2+ and Mg2+, the major anion was HCO3-, and the hydrochemical type was HCO3-Ca. However, owing to the influence of mining activities, the major cations in some tributaries were Ca2+ and Na+, and the hydrochemical types transitioned to HCO3·SO4-Ca and HCO3·SO4-Ca·Na. The ion components of river water in Wudu River Basin were affected by mine water discharge and cation exchange, carbonate rock weathering, silicate rock weathering, and agricultural fertilization. The high concentration of SO42- and Na+in mine water was the primary source of SO42- and Na+in the tributaries of the Wudu River. The method for calculating chemical material balance showed that the contribution rate of carbonate rock weathering ranged from 44.12% to 86.92%, with an average of 74.32%. The contribution rate of mining activities ranged from 3.28% to 37.07%, with an average of 11.61%. Carbonate rock weathering was the main controlling factor of hydrochemical components in the Wudu River Basin; meanwhile, mining activities also had a certain impact on river water chemistry but they showed spatial heterogeneity. The average contribution rates of atmospheric precipitation, silicate rock weathering, agricultural activities, and domestic sewage were 3.75%, 4.67%, 2.85%, and 2.81%, respectively, which had a limited impact on the hydrochemical components of the basin.

Sediment loss modelling framework for the Bradano River Basin, southern Italy, 1950–2020

Hazardous hydrological events cause soil erosion and it is essential to anticipate the potential environmental impacts of prevailing erosion processes that occur at different time-scales. Here, we present the modelling of net soil erosion rates for the Bradano River Basin (southern Italy), based on rainfall erosivity, surface overland flow and transport sub-models. A semi-empirical framework was developed, upscaling point rainfall values based on the Foster-Thornes approach in order to give an insight into monthly and annual soil losses over the period 1950–1958 and 1961 (calibration) and over a longer time-frame (1950–2020: reconstruction). In the 2765-km2 study area, ~ 68% of the sediment mobilized within the basin reached the basin outlet (mean value for 1950–2020: ~ 366 Mg km−2 yr−1). A moderate declining trend in net erosion rates was observed after the 1980s, concurrent with the contraction of cropland in favour of natural vegetation and river channelization. Our results suggest that the parsimonious principle used here seems sufficiently robust to be suitable for applications in other Mediterranean landscapes.

Compression and bending of alkali-activated slag cementitious materials at high temperature

Alkali-activated slag cementitious material (AASCM) with manufactured sand can effectively utilise industrial waste slag and reduce river sand consumption. Steel fibres can effectively improve the mechanical properties of AASCM. Therefore, in this study, the influence of steel fibres and aggregate type on the compression and bending properties of AASCM after high-temperature treatment was investigated. The results show that the mass loss rate, compressive strength and flexural strength loss rate of AASCM with manufactured sand were higher than those with natural river sand at different temperatures. Steel fibres can increase the mass loss rate of AASCM; however, the influence of the steel fibre content on the mass loss of AASCM was not apparent. When the temperature was lower than 600°C, the compressive and flexural strength of AASCM was effectively increased by steel fibres, while, for temperatures higher than 800°C, the mechanical properties of AASCM did not improve, owing to the oxidation failure of steel fibres. Microstructure analysis showed that the number of microcracks in the AASCM increased, owing to the high silicon content of the manufactured sand, and the bond property between the steel fibres and cementitious materials decreased with an increase in temperature.

The Role of Bed Morphology and Channel Curvature on the Redistribution of Momentum in a Series of Meander Bends, Pearl River, USA

AbstractThree primary driving factors are responsible for the lateral flux of streamwise momentum within meander bends: topographic steering of the flow related to changes in channel morphology, rapid changes in channel curvature, and curvature‐driven helical motion. While these factors have been studied previously, their relative contributions to the net redistribution of streamwise momentum within a series of consecutive bends have not yet been fully documented. This study explores the relative contributions of these three mechanisms to the redistribution of streamwise momentum using three‐dimensional velocity data obtained along six consecutive meander bends on the Pearl River (Louisiana, USA) for two different discharges. The magnitudes of lateral momentum flux are systematically compared to spatial series of channel width, bed shape, and channel curvature to elucidate the interactions between channel form and flow structure. Results show that the lateral flux of streamwise momentum is primarily driven by topographic steering with values of momentum flux due to curvature‐driven secondary circulation on average an order of magnitude less than values of flux related to topographic steering. The spatial patterns of the lateral flux components show that momentum redistribution due to topographic steering is highest at the entrance to the bend, and momentum redistribution due to secondary circulation is typically highest downstream of the apex. The results of this study emphasize the important role that interaction between process and form plays in dynamics of natural meandering rivers.

Performance evaluation of Bailey method used in asphalt mixtures containing natural river sands

Performance evaluation of Bailey method used in asphalt mixtures containing natural river sands

Iraqi Water Security: Research on Rights and Possibilities of Solutions

It is Wall Known that Water is the main determinant of the various development programs in any country, as it reflects the investment pattern of cultivated land and the possibilities of expanding it according to the amount of available water: It is also an indicator of industrial quality that relies on water for its production. The main source of water in Iraq is surface water represented by the Tigris and Euphrates rivers, which flow from outside its regional borders, which put Iraq in front of a weakness in terms of the connection of its water resources to several countries, especially Turkey. As the amount of water imports for the two rivers began to decrease a lot starting from the nineties of the twentieth century, this is due to the policy of building dams and water projects at the sources of the two rivers, such as: (Al - GAP). Which hydrogen changes for the two rivers, represented by a decrease in the amount of water incoming, natural rivers. Also, despite the existence of many agreements that deal with regulating the use of water in the two rivers between the three riparian countries. However, Turkey has pursues, through all negotiations related to this file, to relate and empower this case with other cases, including political, security and economic ones, with the aim of obtaining the largest possible gains in its favor regarding this issue, which urges the Iraqi government to realize the seriousness of this file, and to act accordingly. We have seen that the political solution lies in following a specific strategy with multiple and advanced techniques.

Comprehending the practical implementation of permanganate and ferrate for water remediation in complex water matrices

Most previous studies examined permanganate or ferrate oxidation using various emerging pollutants (EPs) spiked in ultrapure water with concentrations of orders-of-magnitude higher than those in natural waters. In present study, we assessed the efficiency of permanganate and ferrate (with ozone as a comparison) at mg L−1 level to remove selected EPs at μg L−1 level in complex water matrices. The efficiency of permanganate and ferrate is more easily affected by the humic acid in synthetic water or dissolved organic matter (DOM) in natural river water compared to ozone. Experiment results revealed that humic acid or DOM were not mineralized by oxidants, but changed in compositional nature, including decreases in the aromaticity, electron-donating capacity, and average molecular weight. At molecular level, condensed aromatic, lignin-like, and tannin-like components in humic acid and DOM are the critical sites being attacked by permanganate or ferrate, the alkene groups and aromatic structures were oxidized predominantly to carboxylic acids. Overall, the present study provided insights into the performance of permanganate and ferrate used for EPs treatment under realistic conditions, as well as alternations of DOM that can be expected following exposure to these oxidants.

Ultralong hydroxyapatite nanowires-based flow-through reactor with high loading of silver nanoparticles for fast continuous catalytic reduction of organic dyes and disinfection of wastewater

The noble metal nanoparticles (NPs) immobilized flow-through reactors have attracted significant attention for the continuous and efficient purification of wastewater contaminated with organic dyes and microorganisms without the need of subsequent recycling processes. However, achieving both high loading of noble metal NPs and high permeation flux concurrently has been a challenge for most reported flow-through reactors. In this study, inspired by the mussel bio-adhesion strategy, we have employed the tannic acid coating method and successfully synthesized Ag NPs-loaded ultralong hydroxyapatite (HAP) nanowires that exhibited an ultra-high loading amount (21.8 wt%). These nanowires were utilized as building blocks alongside chitosan (CS) to fabricate robust and highly porous flow-through reactors (Ag@HAP/CS) for continuous catalytic reduction of organic dyes and water disinfection. The Ag@HAP/CS reactor demonstrates excellent catalytic reduction efficiency (99.3 %) towards MEB at a high flux (2000 L m−2 h−1) with an extremely low concentration of NaBH4 (MEB:NaBH4 = 1:1). This result is attributed to the high loading of Ag NPs, great structural stability in flowing water, and sufficient length along the flowing direction. The reactor also shows remarkable recyclability through water flushing. Ag@HAP/CS exhibits remarkable water disinfection performance against Escherichia coli and diverse bacteria in natural river water, achieving nearly 100 % disinfecting efficiency. This study provides new insights into the strategy of using nanomaterials as intermediate carriers of noble metal nanoparticles to fabricate 3D flow-through reactors, which enable fast and continuous purification of wastewater with ultra-high catalytic efficiency and antimicrobial performance.

Numerical study of the dam-break flood over natural rivers with macroscopic rocks on movable beds

This paper presents a three-dimensional model of dam break flows over fixed and movable beds. As the consequences of a dam break, the model considers the transport of solid particles and deposition due to the momentum of the flow. The movement of the free surface of water and mud is performed by Newtonian and non-Newtonian fluid models, and the solid macroscopic particles movement is carried out by the discrete phase model (DPM) and macroscopic particle model (MPM) models. It has been detected that the model was reliable and well balanced, and could accurately capture the dam break flow movement in complex terrain. Moreover, using the proposed model, a partial dam break of the Mynzhylky Dam was simulated. Even more in the calculation, the presence of mud sediment and solid particles were taken into account, which is very close to the real dam break problem.

Engineering properties and sustainability evaluation of crushed low grade magnesite mortars

China is the country in the world with the most abundant magnesite resources. The ever-increasing deposit of low grade magnesite ore derived from the process of magnesium products has occupied a substantial space and caused environmental damages. In this study, crushed low grade magnesite (CLGM) was prepared and then applied in mortar as fine aggregate to partially or entirely replace natural river sand (30%, 60%, and 100%), while 100% limestone sand (LSS) was applied as the reference group. The findings of this study demonstrated a positive correlation between the ratio of CLGM substitution and the improvement of both engineering properties and sustainable potential in the mortar. Compared with the control group at 28 d, the 100% CLGM mortar exhibited improvements of up to 6% in splitting strength, 25.86% in compressive strength, 16% in porosity reduction, 22.22% in impermeability enhancement, 27.52% in resistance to chloride ion penetration, 21.66% in frost resistance (after 150 cycles), and a remarkable 54.8% in anti-abrasion property. Furthermore, the sustainability evaluation assessed its potential societal value, and highlighted its reduced production costs (down 52.28%) and impressive environmental benefits (notable decreases of 28.3% in ozone depletion potential, 33.2% in land use potential, 38.7% in marine ecotoxicity, and 33.9% in fossil resource scarcity). These findings well demonstrated the feasibility of adopting magnesite tailings as a substitute of conventional aggregate within the construction sector along with substantial economic savings and positive environmental ramifications. The successful application of CLGM mortar in cleaner production can further facilitate the sustainable advancement of environment and construction industry.

The mechanism of dissolved oxygen mixing and atmospheric reoxygenation at the confluence with different flow ratios and junction angles

As the control cell of river networks, the complex hydrodynamic conditions at river junctions pose significant challenges to pollution control and water ecology protection. The purpose of this study is to construct a 3D hydrodynamic model for dissolved oxygen (DO) transport at the confluence, studying its unsteady mechanism under different flow ratios and junction angles. The results of the study show that: i) The atmospheric reoxygenation distribution at the confluence exhibits a typical layered 3D feature, and the strong flow turbulence therein exerts a significant promoting effect on such reoxygenation. ii) The DO transport pattern at the confluence is characterized by the formation of an arc-shaped concentration distribution zone, followed by a contraction towards the opposite bank of the tributary and downstream transportation. A delay in DO concentration increase occurs within the separation area, while lateral oscillations are observed during downstream transport. iii) The flow ratio primarily governs the lateral migration extent of DO, while the junction angle serves as the main driver for downstream transport rate of DO. Increasing both flow ratio and junction angle can expedite mixing efficiency of DO at the confluence. The findings of this study can further enhance the hydrodynamic mechanism for water quality control at the confluent flume, and serve as a valuable reference for improving water environments and protecting water ecology in natural river confluence.

Effects of near-bed turbulence on microplastics fate and transport in streams

Quantifying the impact of hyporheic exchange is crucial for understanding the transport and fate of microplastics in streams. In this study, we conducted several Computational Fluid Dynamics (CFD) simulations to investigate near-bed turbulence and analyze vertical hyporheic exchange. Different arranged spheres were used to represent rough and permeable sediment beds in natural rivers. The velocities associated with vertical hyporheic flux and the gravitational force were compared to quantify the susceptibility of microplastics to hyporheic exchange. Four scenario cases representing different channel characteristics were studied and their effects on microplastics movements through hyporheic exchange were quantitatively studied. Results show that hyporheic exchange flow can significantly influence the fate and transport of microplastics of small and light-weighted microplastics. Under certain conditions, hyporheic exchange flow can dominate the behavior of microplastics with sizes up to around 800 μm. This dominance is particularly evident near the sediment-water interface, especially at the top layer of sediments. Higher bed porosity enhances the exchange of microplastics between water and sediment, while increased flow conditions extend the vertical exchange zone into deeper layers of the bed. Changes in the bedform lead to the most pronounced vertical hyporheic exchange, emphasizing the control of morphological features on microplastics transport. Furthermore, it is found that sweep-ejection events are prevailing near the bed surface, serving as a mechanism for microplastics transport in rivers. As moving from the water column to deeper layers in the sediment bed, there's a shift from sweeps dominance to ejections dominance, indicating changes of direction in microplastics movement at different locations.

Freshwater mussels promote functional redundancy in sediment microbial communities under different nutrient regimes

Abstract Animals are a critical component of biogeochemical cycles. While animal mediated fluxes of nutrients and energy have received considerable attention, the impacts of these fluxes on microbial community structure and function are comparatively understudied. Here, we investigated if freshwater mussel influences on biogeochemical cycling in stream sediment are accompanied by changes in sediment microbial community composition and ecoenzymatic activity, and if these relationships change under different nutrient regimes. We predicted that mussel effects on ecosystem function are reflected by modified sediment microbial communities. We hypothesized that if changes in either sediment ecoenzymatic function or microbial community composition are driven by mussel‐derived nutrient amendments, we should see muted changes in microbial community assemblages or function when a given nutrient is abundant. However, if microbial communities and function are influenced by other mussel functions, then we should see uniform changes regardless of nutrient availability. We transplanted freshwater mussels and natural river sediment to flow‐through mesocosms and monitored changes in microbial community composition over 1 week. Our results indicate that mussels always changed sediment microbial community composition, but the way communities changed was dependent on ambient nutrient concentrations. On the final day we measured the activity of ecoenzymes known to correlate to microbial function and nutrient availability. Mussels homogenized the stoichiometric ratios of ecoenzyme activities, indicating a consistent function of sediment microbes associated with freshwater mussels. Our results suggest that mussels may promote functional redundancy in sediment microbial communities and highlight the importance of animals in controlling biogeochemical transformations under changing nutrient conditions. Read the free Plain Language Summary for this article on the Journal blog.

Temporal evolution of lake level fluctuations under flood conditions and impacts on the littoral ecosystems

Lake levels fluctuations are conditioned by seasonal variability, water resources management and climate change. Recent studies have shown that global warming potentially affects the risk of flooding and that the decisive factor for flood events is not temperature, but precipitation characteristics and hydrological conditions. Flood events have numerous impacts on social, economic and environmental aspects depending on how humans have altered lands, natural rivers and lake dynamics. Flood protection measures can cause conflicts with conservation measures and with ecosystem services because natural capital is not considered able to control floods and to contribute control floods and that it can contribute to human health and safety. In this paper we analysed the flood events in Lake Maggiore for return time periods of 3 – 5 – 10 – 25 – 50 – 100 – 250 – 500 years, considering the flood frequency in the last ten years using 1868-2021 as a reference period. We discussed the probability distribution of flood peaks, the correlation and linear regression between the lake level fluctuations and macroinvertebrates occurrence. We also presented lake coasts flood hazard mapping. The probability distribution that better describes the annual peak level is the Gumbel function, while for spring and autumn flood events the better distribution is the Log-Pearson type III. One of the historical flood events in terms of magnitude was in 2000, characterized by a return time of about 50 years. The last flood event in 2020, was characterized by a return period of about 10 years. Considering the seasonal frequency of flood, the autumn magnitude was higher than the spring one, and the differences between seasonal flood events progressively increased. The results suggested a high probability of a flood event every three years and also a forecast of a flood of about 197 m asl (3.14 m above the average lake level) every 10 years. Raising the lake level will affect the reed bed area from 193 m asl, and it will be more effective at 194.5 m (up to a 10% reduction). During flood events, the whole reed bed area is submerged. As regard macroinvertebrates composition and abundance, the first results show significant negative relationships between all sampling stations altogether vs the abundance of Cladotanytarsus sp. (Chironominae) and nearly significant positive relationships between water levels at Magadino vs Pscectrocladius sordidellus (Orthocladiinae) abundances. These few results are perhaps due to the current limited data availability.

A momentum-based prediction model of backwater rise within and downstream of an emergent canopy in nonuniform flow

Vegetation is widely used to restore waterways and wetland ecosystems. However, emergent canopies create a nonuniform water surface, and predicting the backwater rise is necessary to evaluate the flood hazard. This paper investigates the water surface elevation from downstream to upstream of an emergent canopy in a steady nonuniform flow and predicts the upstream backwater rise. Laboratory flume experiments are conducted on rigid vegetation with varying coverage exposed to different flow rates. The backwater rise and the nonuniformity of vegetated flow are explored based on a momentum equation, and a general formula for backwater rise within and downstream of an emergent canopy is proposed for nonuniform flow. The results reveal that a unified phase diagram of backwater rise can be derived from the momentum model, which presents the variation of both the upstream and downstream water surface elevations and acquires a threshold to identify strong or weak nonuniformity in vegetated flow. The upstream water depth H1 exhibits a nonmonotonic variation, first decreasing and then increasing with water depth H2 at the trailing edge of the emergent canopy. Two partitions of subcritical flow and supercritical flow for the downstream water depth H3 are quantified by the experimental data. The proposed model can be used to accurately predict the backwater rise based on a dimensionless vegetated parameter Cveg and unit discharge q, as demonstrated by both the present and previous experimental results. This work improves the understanding and predictability of the nonuniformity and backwater rise generated by emergent canopies in natural or ecology-restored rivers.

Molecular and optical signatures of photochemical transformation of dissolved organic matter: Nonnegligible role of suspended particulate matter in urban river

Natural dissolved organic matter (DOM) is one of the Earth's dynamic carbon pools and a key intermediate in the global carbon cycle. Photochemical processes potentially affect DOM composition and activity in surface water. Suspended particulate matter (SPM) is the integral component of slow-moving rivers, and holds the potential for photochemical reactivity. To further investigate the influence of SPM on DOM photochemical transformation, this study conducted experiments comparing samples with and without SPM irradiated under simulated sunlight. Surface water samples from slow-moving urban rivers were collected. DOM optical characteristics and molecular features obtained by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) were investigated. Photolabile DOM was enriched in unsaturated and highly aromatic terrestrial substances. Photoproduced DOM had low aromaticity and was dominated by saturated aliphatics, protein-like substances, and carbohydrates. Study results indicated that the presence of SPM had a nonnegligible impact on the molecular traits of DOM, such as composition, molecular diversity, photolability, and bioavailability during photochemical reactions. In the environment affected by SPM, molecules containing heteroatoms exhibit higher photosensitivity. SPM promotes the photochemical transformation of a wider range of chemical types of photolabile DOM, particularly nitrogen-containing compounds. This study provides an essential insight into the more precise simulation of photochemical reactions of DOM influenced by SPM occurring in natural rivers, contributing to our understanding of the global carbon cycle from new theoretical perspectives.

Effects of Submerged Flexible Vegetation on Scalar Transport in an Open‐Channel Flow

AbstractScalar transport in vegetated flow plays an important role in natural river ecology. In this study, a scalar transport model for the flow with flexible submerged vegetation is developed. The turbulent structure and scalar transport characteristics in the flow without vegetation, and with rigid and flexible vegetation are compared. The results show that the scalar diffusion in the flow is mainly governed by the turbulent diffusion outside the diffusion boundary layer. The wake flow downstream of rigid vegetation and the small‐scale Kelvin–Helmholtz (KH) vortices near the top of the canopy are the main reasons to enhance the turbulence intensity in the flow and to significantly increase the turbulence diffusion of scalars. However, the flexible vegetation movement induces the large‐scale KH vortices near the top of the canopy. It also causes to increase the turbulence intensity in the flow, to redistribute the scalar concentration in a wide range, to increase the scalar concentration across the flow depth, and to increase the scalar turbulence diffusion intensity. In the flow with rigid vegetation, the values of the turbulent Schmidt number vary from 0.72 to 1.93 below the top of the canopy, while in the flow with flexible vegetation, they vary from 0.58 to 1.99 only near the top of the canopy. Above the top of the canopy, the Schmidt number ranges from 0.48 to 0.84. The results are useful for the parameterization of scalar transport in natural vegetated rivers.

Investigating the effect of Manufactured sand and Silica Fume on the properties of Concrete

In the present era, concrete is one of the most commonly used construction materials worldwide. Consequently, the demand for natural river sand is increasing. Since the mining of natural sand has already been outlawed by the government in many regions, now it is essential to look into sustainable materials to control natural sand extraction. Hence, manufactured sand (MS) has been shown in numerous studies to be a more practical and environmentally responsible alternative to river sand (RS), which is normally used in the production of concrete. At the same time, the cement industry produces tons of greenhouse gases into the atmosphere, affecting atmospheric conditions. Now, it’s time to look into a suitable replacement material for cement. To investigate the feasibility of using manufactured sand & silica fume in place of river sand and cement under normal climatic conditions fresh, mechanical and durability properties were conducted in the laboratory. Twelve samples of M30 grade cubes and cylinders at desired M sand percentages of 0, 20, 40, 60, 80, and 100 & 0% and 5% variation of silica fume with cement are included in this study as a comparison to the control mix. After 28 days of water curing, a random variation in the properties of concrete was observed in the samples. In this experimental study, SF represents Silica Fume, MS represents manufactured sand, RS represents river sand, FA represents Fine aggregates and CA represents Coarse aggregates.

Analysis of Mechanical Properties and Pore Structure of Mortar Prepared from Municipal Solid Waste Incineration Slag

Abstract The disposal of a large amount of bottom ash generated from the incineration of municipal solid waste has become the focus of research in solid waste and environmentalism. Using municipal solid waste incineration bottom ash (MSWI BA) to prepare mortar can not only solve the problem of insufficient natural river sand resources, but also play a role in treating a large amount of MSWI BA to alleviate urban pressures. In this study, macroscopic properties of mortar were systematically investigated by rheological, mechanical, and drying shrinkage tests, and the influence of MSWI BA on the internal pore structure and interfacial transition zone of mortar has been analyzed by mercury intrusion porosimetry (MIP), scanning electron microscope (SEM) and back scattered electron imaging (BSE). The results show that the rheological model of fresh mortar mixed with MSWI BA as fine aggregate is more consistent with the modified Bingham model, and its plastic viscosity decreases and then increases with the increase of MSWI BA, while the yield stress shows an increasing trend. The compressive strength and splitting tensile strength of mortar decrease with the increase of MSWI BA; the smaller the water-cement ratio and aggregate-binder ratio, the greater the strength loss. The incorporation of MSWI BA improves the flexural strength and compression-flexure ratio of M5/M10 mortar, and the splitting tensile strength of M5 mortar at 28 days is increased by 30 % with 20 % MSWI BA. Additionally, the incorporation of MSWI BA reduces the drying shrinkage properties of mortar and improves the volume stability. At the same time, it increases the number of pores above 50 nm inside the mortar and the content of ettringite at the interface.

Efficiency in using superplasticizer Sika Plastiment - 88 for producing concrete containing manufactured sand in road pavement construction

Efficiency in using superplasticizer Sika Plastiment-88 for producing concrete containing manufactured sand in road pavement construction was presented in this research study. Due to the scarcity of coarse natural river sand more and more seriously, utilizing crushed sand to partially replace natural river sand in making concrete is essential. The initial study provided that the concrete containing 60-80% crushed sand with Sika Plastiment-88 was much better than the concrete containing river sand: Enhancing flexural strength and elastic modulus, reducing significantly construction costs.