Crushed Limestone Sand Research Articles

Shrinkage performance and modelling of concretes incorporating crushed limestone sand with a high content of fillers for pavement slabs

Because of the gradual depletion of gravel and river sand resources and restrictions on quarrying activities to maintain the ecological balance, limestone crushed sand with a high content of limestone fillers is being explored to be used, as an alternative source of supply, in Portland cement concrete (PCC) for rigid pavement. This paper aims to first present mechanical test results carried out on three types of PCC formulated with crushed limestone sand as fine aggregates, devoid of superplasticizers. Since shrinkage cracking is an important problem for rigid pavement, the shrinkage behaviour of these concretes is then experimentally investigated. Furthermore, three existing models (ACI-209, Eurocode2, and triple-sphere models) and a novel-developed model are used to estimate the mixtures’ shrinkage. Results showed that the designed mixtures exhibited normal shrinkage values. The shrinkage modelling revealed that the proposed model well fitted the experimental data. Besides, Eurocode2 and ACI-209 models may be adapted for the case of limestone concretes containing a high content of limestone fillers and then used to accurately estimate their shrinkage strains. However, the triple-sphere model was unsuitable for these concretes and overestimated their ultimate shrinkage since it does not take into account their high filler content. Nevertheless, by adjusting the paste shrinkage expression, the ultimate shrinkage strain values of the tested mixtures were improved.

Performance and durability of self-compacting mortar with recycled sand from crushed brick

The demolition of brick masonry structures and the rejected non-conform bricks are generating a great volume of brick residues. The use of recycled sand from brick residues in the production of mortar could decrease the amount of waste going into landfills and reduce the consumption of natural resources. This paper investigated the feasibility of using recycled sand from crushed brick (RBS) in the self-compacting mortar (SCM). The crushed limestone sand was partially replaced with RBS at different levels (0, 5, 10, 25 and 50%). The properties at fresh state, mechanical behavoir, drying shrinkage and durability of SCM were discussed. As the substitution of limestone sand by RBS increased, the compressive strength of mortars slightly reduced at the age of 28 days (3.3% and 16.9% lower than the reference mortar, respectively for 25% RBS and 50% RBS content); however, which is within the compressive strength requirement in European standard EN 998-2 for masonry mortars. The incorporation of RBS in SCM showed better resistance to chloride diffusion, whereas more attention should be paid to carbonation and sulphate attack. The results indicate that it is possible to manufacture SCM by partially replacing the crushed limestone sand with RBS up to 25% replacement level.

Microstructural examination of carbonated 3D-printed concrete.

The recent interest in 3D printing with concrete has generated great interest on how inhomogeneities arise and affect performance parameters, in particular strength and durability. With respect to durability, of particular interest is how 3D‐printed layer interfaces can impact transport of species of interest, such as moisture, chlorides or carbon dioxide in carbonation processes. This is of particular interest considering that the primary use case of 3D‐printed concrete has been as a lost formwork for a cast structural concrete, and thus it is of interest to determine the carbonation resistance. This study consists of a preliminary look at the microstructure after accelerated carbonation of a 3D‐printed concrete used as a lost formwork. Preferential carbonation is observed in the layer interfaces compared to the bulk of the printed filaments, possibly related to porosity from air voids or a locally high capillary porosity corresponding to the lubrication layer.

Effect of varying silica-limestone sand fines on the physical-mechanical performance of concrete

The use of crushed limestone sand in the concrete industry will be quite possible and imperative for environmental reasons. Many researchers around the world have found that concrete based on 50% substitution of river sand by limestone sand gives better physico-mechanical characteristics. The main objective of this investigation is to search for an optimal percentage of silica-limestone fines resulting from the substitution of half in quantity of alluvial sand by crushed limestone sand in ordinary concrete. The proportions of fines that were tested in this work are 6%, 8%, 10%, 12% and 14%. The obtained results revealed that concrete based on silica-limestone sand and containing 14% of the same type of fines strongly improves the different mechanical strengths and participates in the reduction of 10% and 13%, of the coefficient of capillary absorption and of the porosity accessible to water, respectively, compared to the control concrete. In addition, good statistical relationships between the studied parameters were also found

CRUSHED LIMESTONE SAND: AN EFFECTIVE ALTERNATIVE TO NATURAL SAND IN CONCRETE

Due to its scarcity and the detrimental environmental effect of its extraction, leading to governmental restrictions, the good quality natural rounded siliceous sand became less available in Lebanon. This national and international issue affects the construction industry through the cost and the quality of concrete. Currently, this sand, too fine to be used alone as fine aggregate in concrete mixes, is always mixed with an appropriate percentage of crushed limestone sand to meet the standard grading. The objective of the study is to assess the feasibility of total replacement of natural rounded siliceous sand by crushed limestone sand to avoid the dependency of the construction field on the quality and availability of this material in the Lebanese context. The research program consists of proposing various concrete mixes without natural sand and verifying, following a performance-based approach, that their behaviors can be maintained, at different ages of hardened states, compared to those of the reference concrete incorporating natural sand. The resulting comparisons allow identifying the influences on compressive and flexural strengths of natural sand substitution and of the variations of granular size distribution. At this stage of the study, some preliminary conclusions about the applicability of the solution of natural sand total substitution are proposed.

Effect of total substitution of crushed limestone sand on concrete durability

This article examines the effect of total substitution of siliceous sand by crushed limestone sand in mortar and concrete with regard to durability. Crushed limestone sand is a by-product of quarries containing a significant amount of fines characterised by a ‘spread out’ grain size distribution having a maximum diameter of around 5 mm. An extensive laboratory program was planned to achieve the objectives of this study. Effect of sand replacement on transport mechanism was analysed for two different water/cement ratio by pure diffusion and accelerated migration tests conducted on mortar and concrete samples, respectively. Gas permeability, resistance to strength development under saline curing, carbonation and corrosion tests were also done. The results have indicated the suppression of chloride diffusion coefficients in both mortar and concrete specimens for crushed sand as compared to the siliceous sand. For a given water to cement ratio, the gas permeability coefficients have reduced more than twice for crushed sand as compared to siliceous sand. In addition, the crushed sand concrete has shown better resistance against the strength development in saline curing conditions and corrosion. However, the carbonation depth was observed to be on the higher side for crushed sand as compared to the siliceous sand.

STUDY OF THE WORKABILITY AND MECHANICAL STRENGTH OF CONCRETE IN THE FACE OF UPWELLING (CASE OF THE EL OUED REGION OF ALGERIA)

The objective of this study is to explore the effect of partial and total substitution of river sand by crushing sand in ordinary concrete. Various mixtures were tested to evaluate the properties of fresh and hardened concrete exposed to the water rising from the water table. The river sand was substituted by the limestone sand for the following proportions (0%, 30%, 40%, 50%, 60%, 70%, and 100%). The results showed that, the presence of limestone sand greatly improves the properties of strengh and workability. It was noted that these properties were much higher in the presence of crushed limestone sand compared to silica sand in the concrete.The optimal percentage of river sand substitution by crushed limestone sand is 50%.

Experimental Analysis on Pre-Stress Friction Loss of Crushed Limestone Sand Concrete Beams

This paper presents an experimental research work that evaluates the pre-stress loss caused by friction in crushed limestone sand (CLS) concrete members with post-tensioning. A total of 26 full-scale pre-stressed concrete beams were constructed and tested for the friction loss experiment. The considered variables mainly included the duct-forming materials, wires of tendons and arrangement of ducts. The tensile forces at both active and passive ends of specimen were recorded by steps, and then the pre-stress friction loss for each case was calculated. The result shows that the proportion of pre-stress friction loss in specimen with multi-wire tendons is in the range of 10–40%, with the trend first increasing before decreasing. The pre-stress friction loss in specimen with curve duct accounts for 10–30%. The pressure on the curved part definitely increases the friction when compared with the straight duct. The pre-stress friction loss in specimen with rubber hose reaches nearly 40%, which is larger than the metal bellow and plastic bellow. The suggested values for each case are proposed for a deviation coefficient κ of 0.0017–0.007 and a friction coefficient μ of 0.108–0.858. This can provide reliable theoretical support for the design and construction.

The strength properties of alkali-activated silica fume mortars

In this study, the strength properties of alkali-activated silica fume (SF) mortars were investigated. The crushed limestone sand with maximum size of 0-5 mm and the sodium meta silicate (Na2SiO3) used to activate the binders were kept constant in the mortar mixtures. The mortar specimens using the replacement ratios of 0, 25, 50, 75 and 100% SF by weight of cement together with Na2SiO3 at a constant rate were produced in addition to the control mortar produced by only cement. Moreover, the mortar specimens using the replacement ratio of 4% titanium dioxide (TiO2) by weight of cement in the same mixture proportions were produced. The prismatic specimens produced from eleven different mixtures were de-moulded after a day, and the wet or dry cure was applied on the produced specimens at laboratory condition until the specimens were used for flexural strength (ffs) and compressive strength (fc) measurement at the ages of 7, 28 and 56 days. The ffs and fc values of mortars applied the wet or dry cure were compared with the results of control mortar. The findings revealed that the fc results of the alkali activated 50% SF mortars were higher than that of mortar produced with Portland cement only. It was found that the ffs and fc of alkali-activated SF mortars cured in dry condition was averagely 4% lower than that of alkali-activated SF mortars cured in wet condition.

Multiple contact compression tests on sand particles

Particle crushing has been recognised as being of key importance for many engineering applications. In soil mechanics, this phenomenon has become crucial for defining a complete framework capable of describing the mechanical behaviour of sands. In this study, the effect of multiple discrete contacts on the breakage of grain particles was investigated by crushing coarse grains of a quartz sand and a crushed limestone sand between a number of support particles, thereby varying the number of contacts, i.e., the coordination number. The stress at failure was calculated when the particles broke, which occurred through a number of distinct modes, namely, chipping, splitting or fragmenting, which were observed with the use of a high-speed microscopic camera. The Weibull criterion was applied to calculate the probability of surviving grain crushing, and the fracture modes were observed for each configuration of supporting particles. The data showed that in addition to the number of contacts, the nature of those contacts, controlled by particle morphology and mineralogy, also plays a significant role in determining the strength of a particle. The sphericity affected the strength of the softer limestone sand, while the local roundness at the contacts was important for the harder quartz sand. Catastrophic explosive failure was more often observed in particles with harder contacts, while softer contacts tended to mould relative to their neighbouring particles inducing a more frequent ductile mode of crushing.

Using Crushed Limestone Rocks in Sports Field Rootzones at Different Levels of Bulk Density

Most parks and sports fields are built using native type soils that generally contain excess
 clay and silt contents. Problems associated with these soil types include: easily
 compacted, poor drainage, low water infiltration, low nutrient availability, and reduced
 root growth. Various methods have been used to modify these soils by mixing it with
 sand and other amendments, due to shortage of natural sand in many parts of the world
 and conserving natural resources, it is necessary to find alternative materials; crushed
 limestone sand can be identified as an alternative natural sand in making good quality
 sport field mixture.To assess the possibility of using crushed limestone rocks and to establish a successful
 sports field mixture, (700, 270 and 30 g kg-1) of crushed limestone sand, native soil, andpeatmoss, 
 respectively on mass basis were mixed. 
 Some parameters that are related tosoil mixture of sport field were studied: stability, 
 saturated hydraulic conductivity (Ksat), maximum water holding capacity (MWHC), 
 and each of water holding capacity (WHC) against the gravity and penetration resistance 
 (PRE) of mixture over time were measured at different bulk densities (1.2, 1.3, 1.4, 1.5 and 1.6 Mg m-3). 
 To select the best bulk density (ρb) at constructed sports field rootzones, the coefficient of determination (R2)
 between ρb and each of the studied parameters were determined which were strong
 relation among them. This finding suggests that ρb may control problems during making
 soil mixture. In this research the best ρb of mixture are ranged from 1.417 to 1.510 Mg
 m-3 at which sports field soil provided good stability, good drain, and the quality of the
 playing surface well recognized in unfavorable weather conditions.

Utilization of polymer fibers and crushed limestone sand for stabilization of expansive clays in Amman area

This research aims to improve the physical and mechanical properties of sprawling brown clay, which represents a serious difficulty for construction in Jordan, in particular in the middle and northern regions. Experimental work was conducted using different materials such as polymer fibers, crushed limestone sand, and Type 1 OPC cement mixed with clay at predetermined ratios. Stabilization standard tests were carried out and compressive strength, consistency limits, and shear strength parameters were measured in addition to some physical characteristics. The obtained results showed an improvement in all mechanical properties of the treated clay. The most important being the free swelling, which was reduced significantly by about 6%, i.e. from 7.45 to 1.56% when polymer fibers added to the clay, while the unconfined compressive strength was increased from 1.68 to 5.0 kg/cm2 in soil fiber mixtures. Also, there was a remarkable improvement in the cohesion, from 0.84 to 1.98 kg/cm2 and the angle of internal friction (φ) increased from 12° to 21°. Almost similar results are obtained for other mixes using limestone sand and type 1 cement.

Experimental Study on Engineering and Thermal Properties of Mortar and Plaster Produced With Pumice Aggregate

Abstract Now, it is widely accepted by civil engineers and architects that walls and masonry building units, which are made of pumice, can insulate buildings against both heat and sound, and also reduce the dead load of the building compared to traditional buildings. In this study, pumice was used as a fine aggregate in mortar and plaster instead of traditional crushed limestone sand. This study shows that the properties of pumice mortars indicate lower values compared to limestone mortars for workability durations, time of settings, and fresh and hardened unit weights. Other properties of pumice mortars indicate higher values compared to limestone mortars, such as water absorption, coefficient of capillary water absorption, drying shrinkage, flexural strength, and compressive strength. Also, wall systems made with pumice mortar and plaster show significant benefits in terms of thermal conductivity.

Recyclability of Concrete Pavement Incorporating High Volume of Fly Ash.

Recyclable concrete pavement was made from fly ash and crushed limestone sand and gravel as aggregates so that the concrete pavement could be recycled to raw materials for cement production. With the aim to use as much fly ash as possible for the sustainable development of society, while achieving adequate strength development, pavement concrete having a cement-replacement ratio of 40% by mass was experimentally investigated, focusing on the strength development at an early age. Limestone powder was added to improve the early strength; flexural strength at two days reached 3.5 MPa, the minimum strength for traffic service in Japan. The matured fly ash concrete made with a cement content of 200 kg/m3 achieved a flexural strength almost equal to that of the control concrete without fly ash. Additionally, Portland cement made from the tested fly ash concrete was tested to confirm recyclability, with the cement quality meeting the Japanese classification of ordinary Portland cement. Limestone-based recyclable fly ash concrete pavement is, thus, a preferred material in terms of sustainability.

Effect of quaternary cementitious systems containing limestone, blast furnace slag and natural pozzolan on mechanical behavior of limestone mortars

This paper describes an experimental research on the study of mechanical behavior of crushed limestone mortars of the Algerian Central Saharan Atlas made from a mixture of three mineral additions. Namely; Portland cement, limestone filler, blast furnace slag and natural pozzolan which were simultaneously used to obtain blended cements that contain 50% mineral additions. Mortars have been the subject of a series of normative tests, in order to achieve a characterization, more or less detailed, which allows assessing the quality of these mortars in terms of standards. Three methods for activation of pozzolanic reactivity of BFS and NP were used, namely; mechanical, thermal and chemical methods to activate the pozzolanic reaction of slag and pozzolan at an early age.Three activation methods of pozzolanic reactivity of mineral admixtures were used. Mineral additions were activated mechanically by grinding to 3800cm2/g, and 6000cm2/g Blaine surface area (mechanical method), elevated temperature by curing mortar specimens at 8°C, 20°C and 40°C (thermal method), and chemically by mixing the mixture with 1% of alkaline activator (NaOH) based on the mass of binder (chemical method).Tests were carried out to characterize the mechanical behavior of binary, ternary and quaternary binders of hardened limestone mortars at 2, 7, 28, 90, 180 and 365days. Test results showed that the simultaneous incorporation of LF, BFS and NP in partial replacement to the OPC where the role of the mechanical, thermal and chemical activation of these mineral additions slightly affected the mechanical properties of hardened mortars based on crushed limestone sand at short and long terms (from 2days to 90days).

Pore size distribution of cement mortar prepared with crushed limestone sand

Recently, the use of crushed sand obtained from limestone-quarried is growing especially in the countries where river sand is not quite available. In the paper, the results from an experimental investigation are presented, which evaluates the pore structure of mortar mixtures where fine aggregate is replaced by Crushed Limestone Sand (CLS). The behavior of pore structure of CLS mortar was compared to that of mortars prepared from Nature River Sand (NRS). A Mercury Porosimeter Intrusion (MIP) is adopted to study the behavior of pore size distribution. Both CLS and NRS mortar with four water-cement ratios and five sand-cement ratios are used to determine pore structure. An analytical model was established to compare changes in pore structure for different water cement ratio and volume of sand, and the model was based on the test results.

Mix proportioning and performance of a crushed limestone sand-concrete

Satisfying the ever-growing demand of concrete aggregates poses a problem in many parts of the world due to shortage of natural sand. Moreover, to conserve natural resources and protect civil engineering infrastructures, there is a need to find alternative materials. Crushed stone sand has been identified as a potential substitute material for natural sand in making good quality concrete. The main objective of the present investigation is to determine an adequate mix design method and evaluate engineering properties of crushed limestone sand concrete mixtures in both the fresh and hardened sates. More than thirty concrete mixtures were examined. The results indicate that water demand and cement paste content in crushed sand concrete are generally higher than that used in similar conventional concrete. Good mechanical properties were obtained for concrete using crushed limestone sand as fine aggregates with a superplasticizer. However, a higher than normally used dosage of superplasticizer is required in these concrete mixtures and the optimum dosage of the superplasticizer needs to be determined for each cement and sand content.

Mix proportioning and performance of a crushed limestone sand-concrete

Satisfying the ever-growing demand of concrete aggregates poses a problem in many parts of the world due to shortage of natural sand. Moreover, to conserve natural resources and protect civil engineering infrastructures, there is a need to find alternative materials. Crushed stone sand has been identified as a potential substitute material for natural sand in making good quality concrete. The main objective of the present investigation is to determine an adequate mix design method and evaluate engineering properties of crushed limestone sand concrete mixtures in both the fresh and hardened sates. More than thirty concrete mixtures were examined. The results indicate that water demand and cement paste content in crushed sand concrete are generally higher than that used in similar conventional concrete. Good mechanical properties were obtained for concrete using crushed limestone sand as fine aggregates with a superplasticizer. However, a higher than normally used dosage of superplasticizer is required in these concrete mixtures and the optimum dosage of the superplasticizer needs to be determined for each cement and sand content.

Effect of Mineral Admixtures on Resistance to Sulfuric Acid Solution of Mortars with Quaternary Binders

Abstract This research consists to study the synergistic action of three mineral additions simultaneously added to the cement. This synergistic effect has a positive effect on the sustainability of limestone mortars. Tests were performed on mortars based on crushed limestone sand and manufactured by five quaternary binders (ordinary Portland cement and CPO mixed simultaneously with filler limestone, blast-furnace and natural pozzolan). The purpose of this research was to identify the resistance of five different mortars to the solution of sulfuric acid. Changes in weight loss and compressive strength measured at 30, 60, 90, 120 and 180 days for each acid solution were studied. We followed up on the change in pH of the sulfuric acid solution at the end of each month up to 180 days.

Long-Term Deflections of Crushed Limestone Sand Concrete Beams

Creep tests of three crushed limestone sand concrete beams were conducted. The mid-span creep deflections and creep deflection coefficients of the beams in the first six months were measured. The results show that the creep deflection is significantly affected by the environmental humidity and temperature conditions. The formula of the mid-span creep deflection is derived based on the creep coefficients for simple supported beams. The mid-span creep deflections of beams are calculated using the CEB-FIP 90, ACI 209, and B3 models to predict the creep coefficient separately. Comparisons between the calculated values and experimental results indicate that the coefficients obtained using the ACI 209 model fit the results best. The formula of the creep coefficient is derived from the mid-span creep deflection. The creep coefficient of crushed limestone sand concrete is calculated from the measured mid-span creep deflection, and a best-fit formula is proposed for the creep coefficient.