Types Of Fine Aggregates Research Articles

Fresh and hardened properties of self-compacting mortar containing limestone as fine aggregates

An experimental attempt was presented in this work to reduce the weight of self-compacting concrete by replacing sand entirely with limestone. Therefore, three mixes were prepared, and the same constituent materials were used in these mixes, excluding the fine aggregate type. In the reference mix, conventional sand was employed, but the sand was entirely eliminated and replaced with limestone in the other two. One mix contained untreated limestone, while the remaining was with limestone treated by immersing in the alkaline solution for 24 h. The mixes were contrasted in the fresh and hardened cases. In a fresh situation, the mixes with both limestones' forms were less workable than the reference mix. In hardened case, the sand replacement with limestone reduced the mixes' weight, about 10.9–11.3%. According to the compressive and flexural strengths, the mixes with limestone showed different findings. While the untreated mix gave the smallest strengths, the mix with treated limestone exhibited the most significant enhancement in compressive and flexural strength, where it recorded strengths larger than the reference sand mix.

Concretes containing waste-based materials under active confinement

The newly developed waste-based concrete (WBC) is a viable eco-friendly and sustainable alternative to conventional concrete, which has the potential of decreasing the negative impact of concrete production on the eco-system. Therefore, understanding the behavior of WBCs in structural applications is important. To this effect, this paper presents the first study on the behavior of actively confined WBC under axial compression loading. Two batches of WBC containing ground granulated blast furnace slag (GGBS) as binder and recycled concrete aggregate as coarse aggregate obtained from construction & demolition (C&D) waste were manufactured using two fine aggregate types, namely glass sand (GS) and lead smelter slag (LSS). WBCs were confined at four confining pressures of 5, 10, 15 and 25 MPa using a Hoek cell, and tests were conducted for assessing the effect of the fine aggregate type and confinement level on the axial compressive behavior of WBCs. The results show that, at a given confining pressure, WBCs containing LSS exhibit higher strength and strain enhancement coefficients compared to WBCs containing GS, indicating that confinement is more effective in the former. The results also show that LSS concrete exhibits an axial stress–strain curve with a slightly less steep post-peak descending branch and slightly higher rate of lateral dilation for a given axial strain compared to GS concrete. The comparison between the predictions by an existing accurate model for conventional concrete and the experimental results of this study reveals that WBC containing LSS under active confinement exhibits similar stress and strain relationships to that of conventional concrete. These results are promising and point to the possibility of utilizing the newly developed WBC in structural columns with lateral confinement.

Flexural response of Ultra-High-Performance Concrete (UHPC) hybrid bridge deck connections made with local materials

Although using of UHPC improves the mechanical properties of concrete, it is not widespread used, due to several factors; for instance, its high material cost, special curing requirements, and lack of widely accepted design guidelines. This study aims to find an appropriate Ultra-High-Performance Concrete (UHPC) mixture, using locally available materials. In addition, the flexural response of this locally made UHPC mixture in hybrid bridge deck connections has been studied. The effect of different parameters such as percentage of silica fume, fine aggregate type, glass powder content and steel fiber volume fraction were investigated. The compressive strength results showed that a 28 days-strength of 140.3 MPa (20.35 ksi) has been achieved by using basalt as fine aggregate and 20% silica fume by weight. To investigate the applicability of this locally produced UHPC in bridge joints closure, two full scale, 8 ft. clear span, hybrid bridge deck slabs with UHPC closure were constructed and tested under monotonic loading. The load–deflection behavior of the hybrid connection confirmed that the deflection increased linearly until the initiation of cracks, after that it was increased non-linearly up to the failure of the connection. UHPC experienced less strain than high strength concrete (HSC) under compression. The hybrid connection produced with local UHPC showed moment capacity increase by more than 80% compared to NSC. The Moreover, a moment–curvature analytical model of hybrid bridge deck connection was developed to predict ductility, curvature, and stress distributions in closure connections. The model was able to predict initial stiffness and ultimate flexural moments of UHPC composite connections very well.

Impact of material properties on characteristics of engineered cementitious composite

Abstract Engineered Cementitious Composite (ECC) is one of the high crack-resistive composites due to elimination of the coarse aggregates in the composition. The size of the coarse aggregates is responsible for crack propagation in the structural components. By avoiding this, the characteristics of the ECC mainly depends on the silica sand. This type of fine aggregate is also responsible for self-consolidation characteristics but due to less availability and more cost increases the necessity of alternatives. Indian Zone II fine aggregates are used as alternatives of silica sand in this experimental work. For this, four ECC mixtures were considered. F_1.0_SS and F_1.2_SS are the silica sand based mixtures at fly ash to cement dosage (f/c) of 1.0 and 1.2 repectively. F_1.0_RS and F_1.2_RS are the Indian zone II sand-based mixtures at f/c of 1.0, and 1.2 respectively. The flowability and self-consolidation characteristics of these mixtures were analyzed and specimens were cast to study the hardening and durability characteristics at 28 days curing period. All considered ECC mixtures were showed good self-consolidation characteristics. The mechanical characteristics of ECC are slightly changed from F_1.0_SS to F_1.0_RS and F_1.2_SS to F_1.2_RS.The ECC mixtures with Indian zone II sand showed the same mechanical characteristics compared to silica sand but higher fly ash dosage responsible for the decrease in strength. The durability characteristics also slightly impacted by Indian zone II sand. These results showed Indian zone II fine aggregates can use as an alternative for silica sand.

Influence of Microparticles on Setting Time and Micromorphology of Coal Ash Geopolymers

Geopolymers are inorganic materials with zeolites-like microstructure and mechanical properties similar to those of Ordinary Portland cement materials [1]. However, their properties are highly depending on the constituents (raw material and activator) characteristics, as well as, on the activation particularities (mixing parameters, curing time and temperature etc.). In order to explore the influence of partial replacement of coal ash with two types of fine aggregates (glass and sand microparticles) on micromorphology and setting time, four types of geopolymers were developed. The evaluations were performed by means of electronic microscopy and Vicat method. According to this study, the coal ash replacement with glass microparticles results in an increase in the initial and the final setting time, while the replacement of coal ash with sand particles show a significant decrease. Moreover, the microstructural analysis shows different behaviour, during activation, of the studied microparticles. The surface of the glass microparticles reacts in the alkaline environment, while the sand particles did not. Therefore, the increase of initial and final setting time can be correlated with the dissolution of Si-O from the glass particles, during geopolymerisation.

Correlation Between Ultrasonic Pulse Velocity and Thermal Conductivity of Cement-Based Composites

The thermal conductivity of construction materials is among the main factors influencing the thermal performance of buildings. This property is, thus, extensively demanded for design purposes. The thermal conductivity is especially related to the pore system and the composition of cement-based composites, the same factors that affect their Ultrasonic Pulse Velocity (UPV). In this sense, the present work evaluates the correlation between thermal conductivity and UPV. To this purpose, mortar specimens were investigated, with varying mix proportions, fine aggregate types, and dosages of air-entraining admixture. A satisfactory determination coefficient (R2 > 0.9) was obtained between thermal conductivity and UPV of the mortars when they were grouped under similar components and pore structure. It was observed that the pore system of the mortars tested is more influential to the UPV than their overall porosity. In this sense, a better correlation was found between UPV and thermal conductivity than between thermal conductivity and specific gravity. Additionally, the fine aggregate type presents a significant impact—not only due to its chemical and mineralogical properties but also as a result of the morphology that each aggregate generates within the matrix. In conclusion, this technique potentially presents high applicability to the thermal characterisation of cement-based composites.

Cyclic performance of corroded reinforced concrete short columns strengthened using carbon fiber-reinforced polymer

Steel corrosion in reinforced concrete (RC) members significantly degrades their structural performance, and such corroded members are typically strengthened using fiber-reinforced polymer (FRP). In this study, the cyclic performance of short corroded columns of RC strengthened with carbon FRP (CFRP) is investigated. Seven short RC columns were fabricated and tested under cyclic loading. Of them, six specimens were corroded and one was uncorroded. The parameters considered included the number of CFRP strengthening layers (zero, one, 1.5, and two) and the type of fine aggregate (river sand and sea sand). The hysteretic curves, failure modes, and load–strain relationships of the specimens were compared and are discussed in detail. Furthermore, the equation for calculating the shear resistance of FRP-strengthened short RC columns in Chinese code has been modified to predict the shear resistance of the corroded RC columns strengthened with CFRP. The results show the following: (1) The deformability and energy dissipation of the corroded specimens without CFRP strengthening were significantly lower than those of the uncorroded counterpart. (2) Through CFRP strengthening, these values were improved and were even higher than those of the uncorroded specimen. (3) The modified equation can predict the shear resistance of CFRP-strengthened specimens.

Use of Ceramic Waste as Fine Aggregate in Bituminous Mix in Flexible Pavement Design

In bituminous road construction aggregate is the principal material. Aggregates constitute about 90% or even more of the total construction materials. While selecting aggregate for road construction, search has to be intensified for easily accessible, low-cost natural aggregates and investigate the suitability of indigenous aggregates. Every effort must be taken to select the most economical aggregate which should also perform satisfactorily the design criteria for the road construction conditions. A laboratory investigation was carried out to investigate the design performance of bituminous pavement using different fine aggregates. While constructing bituminous pavement a mix of coarse aggregate, fine aggregate, mineral filler, and bitumen are used. The demand for natural fine aggregate can be reduced by recycling waste tiles chips. Waste tiles, chips aggregate refer to aggregate that has been previously used in the concrete structure as a floor finish. This study easy carried out to investigate the possibility of using waste tiles, chips as a fine aggregate. Therefore, two types of fine aggregate were used to study and compare the behavior of bituminous mixes using waste tiles with that of coarse sand. The Marshall Mix design procedure specified by AASHTO standard was followed in the determination of stability, flow, density, voids in the mixes and the optimum bitumen content. The test specimens were compacted with 50 blows from the consideration of medium traffic. The test results indicated that dense graded bituminous mixes with two types of different fine aggregates satisfy the Marshall Design criteria. From the economic consideration, mixes with waste tiles, chips are comparatively more suitable when available at the construction site. Dense bituminous mix using waste tiles, chips as fine aggregate for medium traffic, is a feasible option from the standpoint of stability, stiffness, deformations and void characteristics.

Evaluation of Geometric Characteristics of Fine Aggregate and Its Impact on Viscoelastic Property of Asphalt Mortar

It has long been recognized that fine aggregate (FA) plays a crucial role in the performance of asphalt mixture, especially for the viscoelastic behavior. In this research, 13 types of FA (1 natural sand, 5 stone chips, and 7 machine-made sands) were selected for investigation. Three indirect indicators (uncompact void content test, flow time test, and standard test method for index of aggregate particle shape and texture ASTM D3398) and three types of direct indicators (form, angularity, and texture) were employed to evaluate the geometric characteristics of FA and conduct comprehensive studies on the indicator system. Meanwhile, the effects of FA geometrical properties on the viscoelastic behavior of asphalt mortar were investigated. The results show that only the form indicator ratio of equivalent ellipse axis (E) and angularity indicator surface parameter (SP) can effectively distinguish different types of fine aggregates. The correlation analysis reveals that the parameters of the four elements in the Burgers model are negatively related to the form index (E) but positively related to the angularity index (SP), while the parameter retardation time ( τ r ) exhibits the opposite. This indicates that the use of less flat-elongated and more angular FA can increase both the overall stiffness and elastic component of asphalt mortar.

Effect of mix component on the mechanical properties of coral concrete under axial compression

Typical influences of mix component on the properties of coral concrete (CC) were analyzed in this paper. Different types of fine aggregates (sea sand and river sand), mixing water (seawater and fresh water) and cementitious materials (cement and fly ash) were considered. An experimental system was developed involving uniaxial compression tests and the use of digital image correlation (DIC) method to investigate the deformation distribution and crack propagation of CC. The variations in failure pattern, strength and deformation of CC were studied. Test results indicated that the failure of CC adopting sea sand and seawater was brittle compared to CC using fresh water and river sand. It was found that axial stress-strain curve (SSC) of ordinary concrete (OC) was different from that of CC. The curvature and the descending slope of SSC obviously changed with the variation of mix components. The seawater improved the strength and elastic modulus of CC compared to fresh water, however, the effect of sea sand was negative. It was verified that prismatic compressive strength of CC with fly ash (FA) developed slowly in early stage, while it increased quickly in late stage. After using different types of aggregates, mixing water and cementitious materials, obvious changes were found in the crack propagation and the axial deformation distribution. However, typical influence of mix component on horizontal displacement distribution was negligible. The cracking of CC was seldom observed before the peak stress when compared to OC, and the seawater and sea sand accelerated the CC crack growth after the peak point. Finally, a numerical stress-strain expression of CC considering the influences of mix component was suggested, which could be used in the theoretical analysis and practical design.

Mechanical Properties and Corrosion Resistance of Cement Concrete Containing Sea Sand or Sea Water

ABSTRACT Through the test of 27 groups of specimens, the influence law on compressive strength and expansion under sea salt corrosion by type of cement, fly ash substitute rate of cement, fly ash substitute rate of fine aggregate, water-binder ratio, type of fine aggregate, and immersion method were analyzed. The corrosion resistance of reinforced concrete under sea water attack was also studied in this research. The experimental results indicate that the influence of various factors on the compressive strength is correlative, and the interaction effects of the type of cement and type of fine aggregate, type of cement and immersion method on the compressive strength are correlative; fly ash substitute rate of fine aggregate, water-binder ratio, type of fine aggregate and immersion were all had significant effects on the expansion at each age. The immersion method had the most significant effect on the expansion. The type of fine aggregate has a significant effect on all tests, but other more correlative factors can be used to improve the deterioration of cement mortar caused by sea sand. Replacement of 10% or 20% aggregate by fly ash gives no apparent improvement in preventing the expansion of cement mortar in sea water exposure. The concrete test results indicate that no serious detrimental effect was found for the corrosion inhibitor in reinforced concrete.

Some Studies on Sustainable Utilization of Iron Ore Tailing (IOT) as Fine Aggregates in Fly Ash Based Geopolymer Mortar

This study presents the sustainable utilization potential of Iron Ore Tailings (IOT) as a replacement material against natural fine aggregates in the preparation of fly ash based geopolymer mortar. Low calcium fly ash is used as the source material and a mixture of sodium hydroxide and sodium silicate is used as the alkaline activator in the mix. Systematic studies such as setting times and compressive strength of the various mixes with different alkali binder ratio’s were investigated in detail. It is to be noted that setting times of the mixes were found to be increasing with the increase in alkali binder ratio (0.4 to 0.8). Alkali binder ratio of 0.6 is found to be the optimum with respect to the compressive strength, irrespective of the type of fine aggregate. Scanning electron microscopy also reveals that microstructure of the fly ash based geopolymer mortar produced had a dense matrix with utilization of the Iron ore tailing. It can be concluded from the study that IOT is found to be a best alternative against the natural sand as a fine aggregate.

The influence of different aggregates on the behavior and properties of gypsum mortars

The structure, behavior and properties of gypsum mortars with different types of fine aggregates were studied. Investigation by scanning electron microscopy shows that the presence of aggregate particles significantly influences the shape and size of gypsum crystals in the interfacial transition zone. The porosity of the gypsum matrix in mortars is greater than the porosity of pure gypsum paste and the pore size distribution shifts towards smaller pores. The shape and size of crystals in the transition zone depends on the surface roughness of the aggregate particles. The grain surface roughness was measured by confocal laser scanning microscopy. The properties of mortars also depend on the grain surface roughness. The workability, setting times and thermal conductivity decrease with increasing grain surface roughness, while the strength and water vapor resistance increase.

Durability of concrete made with natural granular granite, silica sand and powders of waste marble and basalt as fine aggregate

In this study, the durability of concrete made with natural granular granite, silica sand and powders of waste marble and basalt as fine aggregate, was taken into consideration. Limestone was used as coarse aggregate in the production of samples. The properties considered were the compressive strength, resistance to abrasion, freeze-thaw property, capillary water permeability and sulfate resistance. It was observed that the durability property of the concrete made with natural granular granite, silica sand and powders of waste marble and basalt as fine aggregate, was superior to the conventional control concrete. The effect of fine aggregate on the durability of concrete was evaluated. It is understood that the proposed mix provides a better condensed matrix. Moreover, it was observed that the fine aggregate type and its incorporation ratio, also, have great effect on the level of durability. Finally, the results show that addition of natural granular granite, silica sand and powders of waste marble and basalt yields a perfect less permeable concrete.

Strength and durability study of sulphur concrete with replaced fine aggregate

Increase in the technologies and concern about the environmental issues in the present world has led to the requirement of a new construction material which does less harm to the environment and also utilizes the available waste material. Sulphur concrete is type of concrete where cement and water is not used instead melted sulphur which act as binding agent is used to bind the fine and coarse aggregate and the filler material like fly ash together to form a hard concrete. There for study on varies properties of sulphur concrete is very much essential to relate it with normal cement concrete. In this paper various mechanical and durability of sulphur concrete is done. Along with determining a sulphur concrete mix, sulphur concrete with different fine aggregate like beach sand, eco sand and manufactured sand replacing river sand in 0%, 25%, 50%, 75% and 100% is also studied. Durability of sulphur concrete of each type fine aggregate with best compressive strength is also studied. Water absorption, resistance to different chemical environments and rapid chloride ion penetration test is done to determine the superiority of sulphur concrete over cement concrete. Result shows that sulphur concrete can be used in areas subjected to heavy moisture content, where acid activities are more. Strength wise SC give similar result to normal concrete. Another advantage of sulphur concrete is that any type of fine aggregate can be used as filler in SC since it is a water repellent type concrete.

Effect of Aggregate Mineralogy and Concrete Microstructure on Thermal Expansion and Strength Properties of Concrete

Aggregate type and mineralogy are critical factors that influence the engineering properties of concrete. Temperature variations result in internal volume changes could potentially cause a network of micro-cracks leading to a reduction in the concrete’s compressive strength. The study specifically studied the effect of the type and mineralogy of fine and coarse aggregates in the normal strength concrete properties. As performance measures, the coefficient of thermal expansion (CTE) and compressive strength were tested with concrete specimens containing different types of fine aggregates (manufactured and natural sands) and coarse aggregates (dolomite and granite). Petrographic examinations were then performed to determine the mineralogical characteristics of the aggregate and to examine the aggregate and concrete microstructure. The test results indicate the concrete CTE increases with the silicon (Si) volume content in the aggregate. For the concrete specimens with higher CTE, the micro-crack density in the interfacial transition zone (ITZ) tended to be higher. The width of ITZ in one of the concrete specimens with a high CTE displayed the widest core ITZ (approx. 11 µm) while the concrete specimens with a low CTE showed the narrowest core ITZ (approx. 3.5 µm). This was attributed to early-age thermal cracking. Specimens with higher CTE are more susceptible to thermal stress.

Understanding influence of crushers on shape characteristics of fine aggregates based on digital image and conventional techniques

Shape characteristics of fine aggregates, namely angularity and form 2D are greatly associated with the types of rocks, mineralogical compositions, and allied crushing mechanism. Thus, for a given source and aggregate, the type of crusher may play a critical role in producing aggregates having different shape parameters. The present study was undertaken to compare shape parameters of fine aggregates produced from three different crushers, i.e. vertical shaft impactor (VSI), cone crusher (CC) and horizontal shaft impactor (HSI). Basaltic fine aggregates collected from three different crushers was divided into five sizes, namely FA1 (P4.75-R2.36: aggregate passing 4.75mm and retaining on 2.36mm), FA2 (P2.36-R1.18), FA3 (P1.18-R0.600), FA4 (P0.600-R0.300) and FA5 (P0.300-R0.150). The angularity and form 2D values of different sizes and types of fine aggregates were measured using Aggregate Image Measurement System (AIMS) in accordance with AASHTO TP 81. Further, conventional technique namely fine aggregate angularity (FAA) test was used to measure angularity of fine aggregates. Furthermore, Angle of Repose (AoR) test was conducted to identify influence of shape characteristics on particle packing behaviour. The study showed that both the techniques (i.e., AIMS and FAA) could differentiate among the quality of fine aggregates produced from different crushers. However, both techniques resulted in opposite trend in angularity of aggregates. The AIMS measurement showed that angularity and form 2D was highest for aggregates produced from HSI crusher followed by CC and VSI. On the other hand, FAA showed that aggregates produced from CC crusher had maximum angularity followed by VSI and HSI. Conclusively, the AIMS showed that HSI crusher could produce aggregates with highest angularity, while FAA showed that this type of crusher might produce aggregates with least angularity. Curiously, the AoR values showed no significant difference for the fine aggregates produced from different crushers. The interrelation between angularity and form 2D is also discussed in the paper.

Gypsum Mortars with Different Types of Aggregates: Design and Properties

The influence of different types of fine aggregates on behavior and properties of gypsum mortars was investigated. The design procedure and results of some basic physical tests are described. The composition of mixtures was designed in order to minimalize all other impacts than type of aggregate. Four types of fine aggregates of different origin, with different shape and surface of particles were used. The presence of fine aggregate in gypsum increases the bulk density and reduces setting time. Crushed stone with angular rough particles worsen workability and reduce setting time more significantly than aggregates with round and smooth particles.

Evaluation of chloride and water penetration in concrete with cement containing limestone and IPA

This paper investigates the effect of adding inorganic process additions (IPA) and increasing the insoluble residue (IR) on the strength and permeability characteristics of concrete. Also, the effect of supplementary cementitious materials and fine aggregate type is demonstrated. The depth of water penetration per DIN 1048 and the rapid chloride penetration (RCP) test per ASTM C1202 were conducted on twenty six concrete mixes with different cementitious combinations at three different ages (56, 180, and 360days). The IPA addition and the increase in IR had a negligible effect on the strength and permeability characteristics of concrete. In regards to the permeability results, the penetration coefficient (Kw) of water penetrating in unsaturated concrete under hydrostatic pressure per DIN 1048 was estimated based on the average depth rather than the maximum depth of penetration. In addition, the equivalent-steady state diffusion coefficient (Dc_rm) based on the chloride migration rate per RCP test was estimated using the Nernst-Plank equation. By using this equation, the Arrhenius correction factor was applied to account for the “Joule effect”. The results showed a reasonable relationship between the Kw and Dc_rm. Overall, a reliable method was established to predict the Kw based on the DIN 1048 test and a simplified equation based on the charge passed in RCP test was developed to estimate the Dc_rm.

Mechanical Properties of Oven-Dried Mortar Exposed to High Temperature Considering Different Raw Material

Concrete structures can be deteriorated in extreme service conditions especially for fire incidents. For the evaluation of the post-fire performance, analytical methods are very powerful and useful. However, widely applicable mechanical models of fire-damaged material have not yet been proposed. To develop such models, the scale of control volume considering strength, stiffness and deformability is one of important factors. This paper presents an experimental study in which visual observations and mechanical properties of oven-dried mortar after exposed to the fire curves of ISO 834 and ASTM E119 for 90 minutes and to be left to cool down in air were conducted. Mortars were made from two different types of fine aggregate and cement. Experimental results indicate that the raw material made mortar is a prominent factor to introduce the different fire damage characteristics. Meanwhile, the mechanical properties of mortar in fire problem are strongly related to temperature that mortars were experienced to.