Cement Sand Research Articles

Discrete element simulations to predict the response of bio-cemented sands

Discrete element method (DEM)-based numerical models in the YADE environment are used to simulate the constitutive response of uncemented and bio-cemented sands to investigate the influence of boundary conditions, loading and testing conditions, and material types. Both the classical DEM model and the pore scale finite volume (PFV)-coupled DEM model are used to simulate the response of saturated uncemented and lightly cemented sands with a rigid wall boundary under both drained and undrained triaxial compression. A DEM model with flexible boundaries created using particle facet (PFacet) elements is used to simulate undrained triaxial compression of moderately cemented sands, including the influence of confining stress. The PFacet-based model is used to predict the transition from barreling failure to shear banding when the confining stress or the cementation degree increases. The classical DEM model with cohesive bonds of uniform strength is also used to successfully simulate the uniaxial compression response of a sand with an extremely high degree of cementation. Finally, this paper presents a particle-packing model consisting of multiple solid phases for cemented sands based on the understanding that not all particle types will have the same cohesive properties. This multiple solid-phase model is a refinement of the classical DEM model that represents the particle physics more realistically, especially for heterogeneous systems. A preliminary parametric study is carried out considering varying cohesive properties and volume fractions for the different solid phases.

The study of cement sand brick containing kenaf fine particles as sand replacement materials

The study of cement sand brick containing kenaf fine particles as sand replacement materials

An Escalation Over Mechanical Attributes in M30 Type Solid Using Qualified Fill-In by Brick Dust to Cement & Saw Dust to Sand

In this era of civilization, the major industry needful to every household is construction sector which occupies 3rd place among 13 economic sectors in the world. The serious drawback of this sector – one is pollution & second is Scarcity of materials. In the present scenario, the world is stepping towards the new thoughts in pattern to shuffle the contamination by using the proxy materials instead of cement sand & aggregates due to its famine. In this paper of examine talks about the progression of mechanical attributes in concrete. The proxy materials used of mainly two, such that Brick Dust (BD) which is Squander left over the manufacturing of bricks & Saw Dust (SD) is thrift obtained after the wood working operations composed of small chips of wood. The qualified fill in concentrates over the cement with Brick dust with increased measures of frequency like 3%, 6%, 9%, 12%, & 15%, simultaneously on the other side over Fine aggregate with Saw Dust with constant proportion of 5 % respectively for M30 type Solid. Moreover the comparison is held between the conventional Solid & Solid with proxy blends like 0%BD+0%SD, 3%BD+5%SD, 6%BD+5%SD, 9%BD+5%SD, 12%BD+5%SD & 15%BD+5%SD Key Words: Cement, Mechanical Attributes, Brick dust (BD), Saw Dust (SD), & M30 Solid

Macro-micro mechanical behavior of saturated cemented sands during drained triaxial shearing

To enhance the understanding of the macro-micro mechanical behavior of cemented sands, a series of drained triaxial shearing tests were conducted on saturated cemented sands with varying cement contents and confining stresses. These tests incorporated high-performance acoustic emission (AE) monitoring and an environmental scanning electron microscope (ESEM) technique. The results yielded quantitative interpretations of macro-mechanical response, microstructural variation, and AE behaviors. Specifically, increasing cement content led to an exponential reduction in porosity (or pore area ratio) and a power increase in pore number, possibly due to the production of hydration products that segment large pores. Relationships were established among peak strength (or AE hits), cement content, and confining stress. However, AE trends diverged from those observed in peak strength due to microstructural modifications under different cement contents and their resulting differences in micromechanical behavior during shearing. General relationships between AE rate and mechanical parameters were established during the initial shearing stage, regardless of cement content and confining stress. Moreover, AE evolution efficiently characterized subtle variations in failure patterns due to its high sensitivity to failure-induced structural modifications. These contributions have the potential to establish a non-destructive field evaluation framework and provide guidelines for the efficient utilization of cemented soils in geological and geotechnical engineering applications.

Influence of corn cob ash additive on the structure and properties of cement concrete

In accordance with the Sustainable Development Goals (SDGs) concept, there is a need to find technologies that would help make concrete production less energy intensive and more environmentally friendly. One technology involves substituting some mineral components in concrete with rapidly renewable plant-based alternatives. This study aims to establish the essential patterns among the concrete composition, micro-structure, and properties of cementitious composites modified with corn waste. Additionally, it seeks to explore the potential for producing high-quality composites using this waste material. To assess the effectiveness of this kind of waste, the strength of the cement-sand mortar, several characteristics like compressive strength, flexural durability and water absorption of hardened concrete were studied. It is established that introducing corn cob ash (CCA) to substitute a part of the cement up to 16% is justified and allows to obtain mortar and concrete with enhanced properties. CCA has a beneficial impact on the properties of Cement Sand Mortar (CSM) when replacing cement by no more than 15%. The maximum effect was achieved at 10% CCA, and the rise of compressive and flexural strength were 6.06% and 6.32%. In concrete with a CCA amount of 8%, the most impressive growth of compressive strength was 7.14%, and the lowest value of water absorption, which is 10.31% lower compared to the ordinary composition. Including CCA reduces the properties like workability, density of concrete mixtures, and the hardened composite density. The scientific results obtained prove the possibility of using CCA as an effective mineral pozzolanic additive that improves the properties of concrete.

Research on the application of phosphogypsum in magnesium oxysulfate cement: A comparison with sand

Phosphogypsum (PG), as an industrial by-product, has historically suffered from challenges in achieving efficient utilization, resulting in enormous accumulation and environmental contamination. In this study, a certain proportion of PG was employed as a substitute for sand in magnesium oxysulfate cement (MOSC). The effects of PG on the properties, pores distribution, phase composition and microstructure of MOSC were investigated. The results showed that the introduction of PG yielded several beneficial effects, including enhanced volume stability and water resistance, alongside reduced apparent density. However, it also entailed several drawbacks, such as decreased paste flowability, prolonged setting time and increased water absorption rate of the specimens. PG incorporation induced no new crystalline phase, but moderate PG could promote nucleation and development of 5Mg(OH)2∙MgSO4∙7H2O (5∙1∙7 phase) and the group at 10% PG substitution has the highest compressive strength of 68.2 MPa. PG demonstrated the capability to hinder precipitation of Mg(OH)2, thereby enhancing the mechanical properties of MOSC. Due to the affordability and favorable environmental sustainability, PG-MOSC displayed considerable potential for various applications. This study elucidates the mechanism by which PG influences MOSC, providing reference and approach for the recycling of PG.

Self-sensing cementitious geocomposites in rail track substructures

A self-sensing cementitious geocomposite was developed based on laboratory data, and it demonstrated good physical and mechanical properties, durability, and piezoresistivity performance. It consisted of stabilized cemented sand containing multiwalled carbon nanotubes (MWCNTs) with graphene nanoplatelets (GNPs) as conductive fillers. This geocomposite could be used to detect damage based on the relationship between electrical impedance and mechanical performance, making it suitable for use as structural layers in railway lines. In this study, the effects of MWCNTs and GNPs, as well as of degree of saturation, were evaluated on the compaction, secant modulus, resilient modulus, electrical resistance, and piezoresistivity of the geocomposite. Scanning electron microscopy (SEM) and microscopic imaging were used to analyse microstructural alterations induced by varying concentrations of MWCNTs and GNPs. This innovative geocomposite, intended for installation in Portuguese railway lines as part of the EU project IN2TRACK3, is aimed at capturing performance data, identifying structural damage levels, and estimating load intensity, axle numbers, and train speed. The feasibility of its use is discussed based on literature studies and research conducted under the IN2TRACK2 and IN2TRACK3 projects, and its potential advantages over traditional methods for monitoring rail track health are highlighted.

Effect of High Confining Pressure on Ultrasonic Wave Velocities and Elastic Moduli of Cemented Sand

Effect of High Confining Pressure on Ultrasonic Wave Velocities and Elastic Moduli of Cemented Sand

Effect of Strength and Durability of Sand Cement Brick Containing Recycled Concrete Aggregate and Cold Bottom Ash

Introduction The market price of brick has risen sharply due to the insufficient brick supply. Therefore, implementing RCA as one of the alternative materials for sand replacement is significant. The consumption of natural aggregate (NA) can be reduced by using the RCA. It is a good step to utilize recycled concrete to minimize the problem of excess waste materials. The results of using RCA and CBA as sand replacements contribute to better performance in compressive strength as compared to the normal brick. The density of the brick was also reduced by 4.95% as the RCA and CBA took place in the brick. Besides that, the water absorption was decreased when incorporating RCA and CBA in the cement brick due to less free water in the mix and fewer voids. Aims This study aims to ascertain the performance, strength, and durability characteristics of sand cement bricks incorporated with RCA and CBA as partial replacements for sand. Methods Percentages of 1.5%, 3.0%, 4.5%, and 6.0% of CBA and 15%, 30%, 45%, and 60% of RCA were chosen for partial sand replacement. The brick had dimensions of 215 mm in length, 65 mm in depth and 105 mm in width. Density, compressive force, and water absorption tests were undertaken after each of the three varied ratios of water to cement (1:5, 1:6, and 1:7). Results The finding indicates that with the optimum RCA and CBA replacement and the correct water to cement ratio, the performance of the new brick is better than the normal brick. Conclusion The optimum sand-to-cement ratio is 1:6, according to the overall results of selecting the optimal sand-to-cement ratio by density, compressive strength, and water absorption test. However, the result for the density value shows that the average brick density is inferior to the control brick. For all of the sample bricks, the compressive strength was best at a sand cement ratio of 1:6. However, as each of the samples complies with the British Standard criterion of less or equal to 15% absorption, it was determined that the sand cement brick's capacity for water absorption was sufficient.

Multi-objective optimization of sustainable cement-zeolite improved sand based on life cycle assessment and artificial intelligence

Background Cement-zeolite improved sand can be used in diverse civil engineering applications. However, earlier research has not duly optimized its production process to attain best mechanical strength, lowest cost, and least environmental impact. This study proposes a multi-objective optimization approach using back-propagation neural network (BPNN) to predict the mechanical strength, along with an adaptive geometry estimation-based multi-objective evolutionary algorithm (AGE-MOEA) to identify the best parameters for cement-zeolite-improved sand, filling a long-lasting research gap. Methods A collection of unconfined compression tests was used to evaluate cemented sand specimens treated with stabilizers including portland cement (at dosages of 2, 4, 6, 8, and 10%) and six dosages of natural zeolite as partial replacement for cement (0, 10, 30, 50, 70, and 90%) at different curing times of 7, 28, and 90 days. The study further conducts a detailed analysis of life cycle assessment (LCA) to show how partial zeolite replacement for cement impacts the environment. Through a tuning process, the BPNN model found the optimal architecture and accurately predicted the unconfined compressive strength of cement-zeolite improved sand systems. This allowed the AGE-MOEA to optimize zeolite and cement dosages, density, curing time, and environmental impact. Results The results of this study reveal that the optimal range of zeolite was between 30-45%, which not only increased cemented sand strength, but also reduced the cost and environmental impact. It is also shown that increasing the zeolite replacement to 25-30% can increase the ultimate strength of cemented sand, yet exceeding this limit can cause the strength to decrease. Conclusions Zeolite has the potential to serve as an alternative for cement in applications that involve cemented sand, while still achieving mechanical strength performance, which is comparable or even superior. From an LCA standpoint, using zeolite as partial cement replacement in soil improvement projects is a promising alternative.

Mechanical and Physiochemical Characteristics of Sandcrete Blocks Produced with Sustainable Biomaterials

The quest for sustainable construction materials is rapidly increasing; due to health hazards associated the traditional construction items. This research goal is to investigate how sugarcane bagasse ash (SBA), crushed periwinkle shells (CPS) and cassava starch (CS) incursion affects the engineering performance of sandcrete blocks, and the physiochemical qualities of their leachate. SBA was incorporated at a rate of 5, 10, 15 and 20% as substitution for cement; treated CPS (TCPS) and untreated CPS (UCPS) were add at a rate of 10, 15, 20 and 25% as partial replacement for sand; while 1% CS was added as integrity enhancer. A consistent cement–sand mix ratio of 1:8 and corresponding water–cement (w/c) ratio of 0.55 were employed across all 17 experimental units; and the blocks were cured using the irrigation technique. Likewise, the blocks were subjected to leaching condition (immersion in water) to collect their leachate. Chemical compositions of the SBA, sand, cement, CS and TCPS and UCPS were examined using the x–ray fluorescent technique, while the mechanical and physiochemical parameters of the blocks were studied in harmony with the American Society for Testing and Materials standards. The results obtained revealed that the mechanical and physiochemical qualities of the blocks were dependent on the volume of the bio–materials incorporated into the sandcrete. Furthermore, the findings showed that an environmentally friendly high–strength lightweight sandcrete blocks, meeting international requirement of 3.45 N/mm2 can be produced by incorporating 10% SBA, 15% TCPS and 1% CS into the sandcrete block. The research highlights the possibility of using agricultural waste materials in achieving sustainable materials for the housing industry.

Study on dynamic mechanical properties and microstructure of basalt fiber reinforced coral sand cement composite *

This study investigates the impact of basalt fiber on the static and dynamic compression of coral-sand cement-based composites, as well as the mechanisms for strengthening and toughening. The samples of basalt fiber-reinforced coral sand cementitious composite (BFRCSCC) with varying fiber volume fractions (0%, 0.2%, 0.4%, 0.6%, 0.8%) underwent quasi-static mechanical tests and impact dynamic tests using an MTS universal testing machine and a split Hopkinson pressure bar (SHPB). This study investigates the mechanical properties of BFRCSCC, focusing on static and dynamic compressive strength, dynamic stress-strain curve, strain rate effect, failure strain, toughness analysis, and energy dissipation mechanism. In terms of microstructure, specimens of BFRCSCC were tested using scanning electron microscopy (SEM). The results indicate that basalt fiber can significantly enhance the quasi-static compressive strength (fc)and dynamic compressive strength (fd)of coral sand cement-based composite materials. When the basalt fiber content is 0.4%, the static and dynamic compressive strength of BFRCSCC increases by 28.78% and 37.25% respectively compared to ordinary concrete. The analysis from a micro perspective indicates that the incorporation of basalt fiber in the concrete matrix enhances the hydration reaction between cement and the BFRCSCC interface. The spatial structure formed by basalt fiber contributes to the excellent toughening effect on the mechanical properties of BFRCSCC. As the content of basalt fiber increases (≤0.4%), the bridging effect becomes stronger. The dynamic increase factor (DIF) and toughness index of BFRCSCC exhibit a significant positive correlation with the strain rate effect. Basalt fibers can help drive the hydration products to fill the cracks or voids in the cement matrix, thereby increasing the material's density and enhancing the impact resistance of coral concrete. This can be utilized in practical engineering projects with high dynamic load demands.

Mechanical Properties of Bricks Containing Sago Fine Waste as Cement Replacement Material

Due to the country's expanding population and the resulting growth of the building industry, brick is one of the most crucial materials used in construction projects in Malaysia. Producing large amounts of bricks requires a lot of cement yet this method has environmental consequences due to increasing carbon emissions into the atmosphere. Therefore, this study aims to use partial Sago Fine Waste (SFW) to replace the cement. About 60 tonnes of sago trash are dumped into the closest river every day during the production of sago starch. To protect the environment and contributing to sustainable development, this study has been conducted on the production of bricks from waste materials. For this study, the brick specimens were prepared using 0%, 1%, 3%, 5%, 7% and 9% of SFW with a water-cement ratio of 0.6 fixed at 1:3 sand cement ratio. The total specimens that were produced for testing are 72 bricks. The water curing for concrete has been conducted at 7 and 28 days. The overall results revealed that both density and compressive strength are decreases as the percentages of SFW increases. The initial rate of absorption increases due to the increasing percentage of SFW. However, all the results obtained are still met the requirements. Based on the findings, the optimum percentage SFW are SFW1W0.6 with strength 5.18 MPa. The optimum brick properties of SFW1W0.6 is normal weight with density 2092.86 kg/m3 and lowest initial rate absorption with 0.91 kg/m3.min.

Mechanical and energetic properties of rock-like specimens under water-stress coupling environment

AbstractSoft rock has the properties of low strength, poor integrity, and difficulty in core extraction. In order to study the deformation and failure of soft rock, this study used fine river sand as aggregate, cement and gypsum as bonding materials, and borax as a retarder to produce cylindrical rock-like samples (RLS) with a sand cement ratio of 1:1. Uniaxial compression tests were conducted on RLS under DIT (different immersion times) (0, 4, 8, 12, 24, and 48 h) in the laboratory. The mechanical and energy properties of RLS under water-stress coupling were analyzed. The results showed that the longer the IT of the RLS, the higher their water content (WC). As the moisture time increases, the uniaxial compressive strength, elastic modulus (EM), and softening coefficient (SC) of the sample gradually decrease, while the rate of change of EM is the opposite. The fitted sample SC exhibits a good logarithmic function relationship with WC. During the loading process of the sample, more than 60% of the U (total energy absorbed) during the loading process of the sample is accumulated in the form of Ue (releasable elastic energy), while less than 40% of U is dissipated by the newly formed micro cracks during the compaction, sliding, and yield stages of the internal pores and cracks of the sample. The U before the peak and the Ue of the RLS decrease exponentially with the moisture content; the relationship curves of Ue/U (released elastic energy ratio) and Ud/U (dissipated energy ratio) of RLS during uniaxial compression with the σ1/σmax (axial stress ratio) can be divided into three stages of change, namely the stage of primary fissure compaction and closure (σ1/σmax < 0.25), continuously absorbing energy stage (0.25 < σ1/σmax < 0.8), and energy dissipation stage (σ1/σmax > 0.8); the D (damage variable) was defined by the ratio of Ud (dissipated energy) to the Udmax (maximum dissipated energy) at failure time of RLS, the fitting of the relationship between the damage variable and axial strain conforms to the logistic equation.

Feasibility Study of Material Deformation and Similarity of Spatial Characteristics of Standard Coal Rocks

The comparison between similar materials and original coal rock is the basis for similar simulation experiments in coal mines. The differences in mechanical properties, acoustic characteristics, and damage laws between similar materials and the original coal rock are of great significance for similar simulation research, to reveal objective laws. First, materials similar to coal rock with similar theoretical ratios were taken as the object of research, and the sand–cement ratio, the carbon paste ratio, and the water content were determined by multivariate linear regression to accurately match the ratios. Second, by using acoustic emission and digital scattering technology to explore the acoustic law, deformation characteristics, and spatial feature similarities of the materials similar to coal rock, the acoustic emission evolution law of the original rock was found to be the same as that of the similar materials. Digital scattering was able to describe the localization of strain in the similar materials, and the correlation between the overall deformation and the local deformation was explored. This indicates that materials similar to coal rock can effectively simulate the deformation of actual coal rocks. Lastly, these materials were found to allow effectively simulating the deformation characteristics and spatial properties of actual coal rock, which provides an important experimental means and method for similar research in the field of coal rock engineering.

A State-Dependent Elasto-Plastic Model for Hydrate-Bearing Cemented Sand Considering Damage and Cementation Effects.

In order to optimize the efficiency and safety of gas hydrate extraction, it is essential to develop a credible constitutive model for sands containing hydrates. A model incorporating both cementation and damage was constructed to describe the behavior of hydrate-bearing cemented sand. This model is based on the critical state theory and builds upon previous studies. The damage factor Ds is incorporated to consider soil degradation and the reduction in hydrate cementation, as described by plastic shear strain. A computer program was developed to simulate the mechanisms of cementation and damage evolution, as well as the stress-strain curves of hydrate-bearing cemented sand. The results indicate that the model replicates the mechanical behavior of soil cementation and soil deterioration caused by impairment well. By comparing the theoretical curves with the experimental data, the compliance of the model was calculated to be more than 90 percent. The new state-dependent elasto-plastic constitutive model based on cementation and damage of hydrate-bearing cemented sand could provide vital guidance for the construction of deep-buried tunnels, extraction of hydrocarbon compounds, and development of resources.

Centrifugal and Numerical Modeling of Seismic Behavior of Pile Foundation in Layered Ground of Dense and Cemented Sand

Centrifugal and Numerical Modeling of Seismic Behavior of Pile Foundation in Layered Ground of Dense and Cemented Sand

A review of mix design terminologies for cement admixed sandy clay

In densely populated countries, underground construction and land reclamation could be possible options to solve the demand for land space, thus securing sustainable long-term development of the nation. For example, in Singapore, land reclamation has been widely conducted using excavated materials from underground development. The excavated materials are commonly marine clays that contain sandy soils. To improve the mechanical properties of these soft soils, cement-treated soil stabilization is popularly adopted. In fact, many researchers have investigated the properties of pure cemented clay or pure cemented sand using conventional design parameters such as water content (water/solids) and cement content (cement/dry soil). However, can these terminologies be still used to accurately examine the role of sand in cemented sandy clay mixtures? Through unconfined compression testing, it is herein shown that the use of existing mix design approaches in the literature cannot properly explain the variation of strength with sand content for cemented sandy clay mixtures. A new mix design approach is thus proposed in this study, which ensures that the role of sand in a cemented clay matrix can be quantified.

Mechanical Properties and Micromechanism of Calcium Sand–Cement Mortar Modified With Zirconium Dioxide and Basalt Fiber

In this paper, the modification effect of basalt fiber (BF) and nano‐zirconium dioxide on calcareous sand–cement mortar was studied according to the actual situation of the island construction project. Mechanical tests were carried out on specimens of calcareous sand–cement mortar doped with different dosages of BFs and nano‐zirconium dioxide, and the effects of BFs and nano‐zirconium dioxide on the compressive properties of calcareous sand–cement mortar were analyzed by using the unconfined compression test study and the modification mechanism was elaborated by using: (1) the stress–strain curves of calcium sand–cement mortar are all softened hump‐like convex curves, and the residual stresses tend to a stable constant value. (2) BF at 0.6 wt% was the optimum dosing and increased the compressive strength by 66%–94%, 55%–65%, and 44%–63%, respectively, compared to that of calcareous sand–cement mortar as the age of maintenance increased. The compressive strength of nano‐zirconium dioxide–cement was increased by 49.2%, 79.1%, 101.1%, and 95.4% at the dosage of 4%, 6%, 8%, and 10%, respectively, and the optimum dosage was 8% compared to that of calcareous sand–cement mortar. (3) BFs are interspersed in the cement mortar, forming a dense mesh structure, wrapping and binding the cement mortar, and playing the role of anchoring reinforcement under external load. Nano‐zirconium dioxide due to its filling and induced catalytic role in the formation of a certain plate‐like structure, so that it and the calcium sand–cement mortar between the overall more compact, improving the compactness of the specimen.

Experimental Investigation on Performance of Ferrock Concrete

Today, the construction of buildings and infrastructure has increased as a part of development, resulting in a significant demand for concrete and cement. The large-scale production of cement and extraction of river sand can have negative impacts on environment and depletion of natural resources. Due to the production of 1 ton of cement produces 0.9 ton of CO2 emissions. To mitigate this pollution a green substance called as FERROCK (Iron dust 60%, Flyash20%, Metakaolin 10%, Lime powder 8%, Oxalic acid 2%) is used as a partial replacement of cement with selected ratio (10%, 20%, and 30%) by weight of cement. This study includes the complete replacement of river sand with M sand (85%) and glass powder (15%) to reduce the usage of natural sand (river sand) for the selected grades of concrete M40, M60 by performing the mechanical and durability test on the designed concrete grades with selected ferrock ratios, the mechanical and durability properties were enhanced with 20% ferrock replacement by weight of cement in concrete.