Quartzite Aggregate Research Articles

Moisture susceptibility of HMA containing high siliceous quartzite aggregates: a comparative study of different hydrated lime addition methods

ABSTRACT Hydrated lime (HL) has been used in asphalt mixtures to enhance the resistance to moisture damage in three ways, viz, as a filler, bitumen additive, and coating to aggregates. Quartzite aggregates are weaker in adhesion to asphalt binder due to higher silica content in chemical composition. This study compared three HL addition mechanisms to improve moisture-induced damage in hot mix asphalt made with high siliceous quartzite aggregates. Extensive experimental investigations were carried out, such as indirect tensile strength (ITS), tensile strength ratio (TSR), and fracture energy (FE), to compare the effects of HL addition with respect to conventional mixes. The ITS and TSR results found that HL-additive and HL-coating methods improved the resistance to moisture damage. Compared to control mixtures, HL-treated mixtures showed 20–25 percent higher TSR values. Meanwhile, the HL-filler method showed better resistance to fracture than the other two methods, offering better resistance to fracture in the field.

Chemical Treatment of Quartzite Aggregates and Its Effect on Moisture Susceptibility of Asphalt Mix

Chemical Treatment of Quartzite Aggregates and Its Effect on Moisture Susceptibility of Asphalt Mix

CONCRETE ON QUARTZITE AGGREGATES

In the post-war period, Ukraine will need a large number of aggregates to repair and rebuild destroyed and damaged objects of transport infrastructure, including roads, airfields, and parking lots. To expand the raw material base of such construction, in addition to traditional high-quality aggregates from crushed granite, quartz sand and manufactured sand, it is advisable to use some types of waste and secondary products from various industries. They must meet the basic requirements for density, strength, frost resistance. These include a by-product of iron ore mining, quartzite. The use of quartzites as aggregates for cement concretes has certain difficulties due to their characteristics. This is reflected, first of all, on the strength of the concretes in which they are included. In this article, the features of the influence of quartzite aggregates on the strength of cement concretes are considered. Studies that have been carried out on mixtures of different mobility have shown that dusty particles, which are part of quartzite, have a positive effect on the structure of concrete.

Moisture susceptibility of chemically treated quartzite aggregates in hot mix asphalt

ABSTRACT Quartzite aggregates are widely available siliceous aggregates that are weak in adhesion with asphalt binder. This study focused on improving the moisture susceptibility of hot mix asphalt (HMA) using chemical treatments to quartzite aggregates. Hydrated lime (HL), nano-organosilane additive (NOS), and two silane coupling agents (SCA) were used to treat aggregates. Moisture susceptibility was investigated using different tests such as retained stability, indirect tensile strength (ITS), and fracture energy. Scanning electron microscope (SEM) analysis was conducted to identify surface modifications and the treatment mechanisms, it was observed that HL treatment forms the rough surface over the aggregate by precipitating CaCO3, on the other hand, SCA treatments make perfect hydrophobic nano-layer over the surface of the aggregates. After the boil test, Coating retention was quantified with image processing, and coating retention was increased to greater than 95 percent compared to control mixes (i.e. 40–45 percent). The tensile strength ratio (TSR) of HMA with treated aggregates was increased by 20–25 percent to control mixes. HL and SCA-1 showed better TSR and fracture energy ratio (FER). Based upon the study results, it was concluded that chemical treatment methods can able to reduce the moisture induce damage of HMA with quartzite aggregates.

Feasibility of Using Sugar Cane Bagasse Ash in Partial Replacement of Portland Cement Clinker

This work presents a technical and economic study using sugar cane bagasse ash (SCBA) to partially replace Portland cement clinker. To evaluate the technical viability, the replacement rates of 10, 20, and 30% of Portland cement were used in the experiments. The ashes used were in the following conditions: (i) as collected (AC), (ii) ground (G), and (iii) re-burnt and ground (RG). Three composition parameters were used in the mortar mix procedures: (i) mix with water factor/fixed binder in volume, (ii) mix with water factor/fixed binder in weight, and (iii) mix with the fixed flow. After the technical feasibility analysis, the benefit of the substitutions and an analysis of the relationship between cement consumption and the acquired compressive strength, correlating with possible economic costs, were discussed. SCBA AC was not suitable for the partial replacement of Portland cement clinker. SCBA G presented a satisfactory performance and SCBA RG was the ash that presented the best performance in the partial replacement of Portland cement clinker. For the same levels of compressive strength, the consumption of Portland cement per cubic meter of concrete reduced; from this, the cost of concrete and mortar could be reduced by 8%, with the ash having the same value as cement. Furthermore, the use of SCBA RG at 30% inhibited the alkali–silica reaction (ASR) in concretes with a reactive basalt and quartzite aggregate. SCBA G (20 and 30%) and SCBA RG (10 and 20%) inhibited the ASR in concretes with a reactive basalt aggregate and reduced the expandability in concretes with a reactive quartzite aggregate. Another point to highlight was the durability shown by the cements with SCBA, which, 900 days after the accelerated test of expansion by the alkali–aggregate reaction, maintained high levels of flexural strength when compared to the results obtained before the accelerated test of expansion. The present work concluded that using sugar cane bagasse ash to replace Portland cement is feasible from a technical, environmental, and economic perspective.

Investigating the Relationship Between Moisture Content and Dry Density on Different Gradations for Road Base Granular Materials

California Bearing Ratio (CBR)in granular materials is the key technical characteristic of layers in flexible pavement. The CBR value is a way to measure the material stiffness used in the pavement design procedure for the road base layer depending on the aggregate types. Road base layers’ ultimate role in the flexible pavement is to spread loading evenly over the sub-grade from the loading of vehicles throughout the design life. Among the factors affecting the material's bearing capacity, aggregate gradations are one of the most important parameters that give a considerable result. This study was carried to evaluate the effects of different aggregate gradations using granite, basalt, and quartzite aggregates on the bearing capacity of the granular materials. Further analysis on the base course layer’s upper and lower gradation limit were conducted to identify the bearing capacity of the layer, through a series of aggregates physical tests and strength tests. The results indicated that physical properties of the selected aggregates complied to the Public Works Department (PWD) Specifications (2008) for soaked and un-soaked condition. For both soaked and un-soaked conditions, the samples with lower limit gradations showed higher stress values compared to upper limit gradations for all three types of aggregates. Granite showed higher CBR values for both, soaked, and un-soaked conditions, followed by basalt and quartzite at upper and lower limit gradation. Un-soaked granite samples with lower limit gradation showed 60.5% increment in strength compared to un-soaked upper limit gradation, followed by quartzite 53.6% and basalt 9.94% respectively. The results indicated that strength is highest in the lower limit gradations where the use of coarse-grained aggregates could significantly increase the strength.

Building the cooling roads with high thermal conductivity pavements to relieve urban heat island effect

This study aims to propose a new highly thermally conductive pavement (HTCP) structure and evaluate the cooling effect of the structural layers and near-surface air. The HTCP consisted of coarse quartzite aggregates with high thermal conductivity instead of limestone. The HTCP and conventional asphalt pavement layers were placed in the environmental chamber. The incandescent lamp was used to simulate solar radiation to analyze the air temperature changes of the structural layers and near-surface air. The test results show that quartzite improves the thermal inertia of asphalt pavement layers. And the HTCP effectively transfers the heat accumulated in the upper layer and reduces the daily temperature of structure layers and near-surface air. However, HTCP releases more sensible heat at night, negatively impacting the urban heat island effect. This research contributes to the improvement of HTCP from an aggregate perspective and provides new ideas for mitigating the UHI effect.

Flexural strength and fatigue properties of interfacial transition zone at the microscale

In this study, the flexural strength and fatigue properties of interfacial transition zone (ITZ) were experimentally investigated at the micrometre length scale. The hardened cement paste cantilevers (150 × 150 × 750 μm3) attached to a quartzite aggregate surface were prepared and tested under the monotonic and cyclic load using a nanoindenter. The measured flexural strength of the ITZ (10.49–14.15 MPa) is found to be one order of magnitude higher than the macroscopic strength of ITZ reported in literature. On the other hand, the fatigue strength of the ITZ is lower than that of bulk cement paste at same length scale, measured previously by the authors. The microscopic mechanical interlocking and the electrostatic interaction between aggregate surface and hydration products are thought to contribute to the bond strength of ITZ. This study provides an experimental basis for the development of multiscale analysis of concrete subjected to both static and fatigue loading.

Diagnosis of ASR damage in highway pavement after 15 years of service in wet-freeze climate region

Diagnostic tests were carried out on specimens drilled from a section of jointed, unreinforced highway pavement after 15 years of service. The section of highway was exposed to heavy road traffic, environmental actions of wet-freeze climate zone and associated winter maintenance including application of deicing salt. Premature pavement damage was manifested by visible cracking, mostly along transverse joints and in slab corners. Tests performed on core specimens included petrographic analysis of concrete and its components, using optical and scanning electron microscopy, also evaluation of elastic and transport properties, expansion potential, cracks and air void system. Numerous cracks in the grains of coarse quartzite aggregate were found. Reactive forms of quartz in quartzite aggregate - microcrystalline and cryptocrystalline quartz - were abundant. The gel-like products in cracks in quartzite grains and in surrounding cement paste were identified as alkali-silica reaction products. Expansion of specimens exposed to an alkali-silica reaction-promoting environment indicated the potential for further development of such reaction. Substantial cracking and reduction of modulus of elasticity was correlated with the presence of reactive quartz in quartzite aggregate. The role of additional destructive factors, such as the impact of heavy vehicles traffic and freeze-thaw aggression was indicated by greater cracks in the slow traffic lane compared than in the emergency lane, associated with local marginal air entrainment of concrete.

A Study of Adhesion in Foamed WMA Binder-Aggregate Systems Using Boiling Water Stripping Tests.

The paper investigates the phenomena of adhesion in binder-aggregate systems produced to reflect warm-mix asphalt with water-foamed bitumen. The investigated materials included limestone and quartzite aggregates and a total of four asphalt binders: 50/70 and 45/80–55 bituminous binders obtained from two sources. The adhesive bonding between the asphalt binders and aggregates was evaluated in boiling water stripping tests, which results were quantified using digital image analysis. The bituminous binders were additionally tested for their dynamic viscosities, and their chemical composition was probed using FTIR spectroscopy. The tests were carried out using traditional liquid and foamed bituminous binders on samples prepared at temperatures characteristic of hot-mix asphalt and warm-mix asphalt production (20 °C decrease). The use of foamed binders yielded higher values of residual asphalt binder coverage of the aggregates. Limestone aggregates provided superior adhesion, with the lowest result amounting to approximately 88%, while with quartzite aggregates, the results ranged from approximately 40% to 87%. The refinery from which the asphalt binders were sourced had a significant influence on the results; however, the additional rheological and chemical analyses were insufficient to explain those differences. It was concluded that the process of asphalt binder foaming, per se, may have a beneficial impact on the resistance of the asphalt binder-aggregate system to the action of water.

Evaluation of a biofuel residue-derived recycling agent with a low carbon footprint

Protecting environment, conserving natural resources by recycling and replacing non-renewable materials with renewable ones, reducing material cost, and utilizing sustainable processes are actively pursued by asphalt industry. Consistent with those efforts, Recycling Agents (RAg) with different technologies have been introduced which allow using high amounts of Reclaimed Asphalt Pavement (RAP) in construction of new pavements. RAgs, depending on their type and chemical composition, affect the mechanical properties of the asphalt binders differently. This study was undertaken to characterize effectiveness of using a relatively new plant-based RAg produced from biofuel residue in a low-carbon footprint process when used in asphalt binder blends containing a high amount of RAP. Effects of using different amounts of RAg, namely 0, 4, 6, and 8% (by binder weight) incorporated in a blend of a PG 58-28 containing 30% laboratory-simulated RAP binder (RAPsb) on binder blends’ rheological properties were studied by testing them in a dynamic shear rheometer and a bending beam rheometer and by conducting Multiple Stress Creep Recovery (MSCR) tests. In addition, effect of using RAg by its optimum dosage in a blend of PG 58-28 binder containing 30% RAPsb on its adhesion with granite and quartzite aggregates and moisture-induced damage was characterized. As a result, a Superpave grade of PG 58-34 was found to be achievable by incorporating 4% RAg in a blend of PG 58-28 and 30% RAPsb. Also, incorporating 4% RAg in a blend of PG 58-28 and 30% RAPsb improved the fatigue resistance of the RAPsb-laden binder to an extent which exceeded that of the neat PG 58-28. Furthermore, an elastic recovery response significantly higher than and a non-recoverable creep response equivalent to those observed in neat PG 58-28 were achieved by incorporating 4% RAg in a blend of PG 58-28 and 30% RAPsb, both having an MSCR grade of PG 58S. Finally, an overall improvement in resistance to moisture damage in PG 58-28 binder containing 30% RAPsb with granite and quartzite was observed as a result of incorporating 4% RAg in the blend.

Prospects of Replacing Natural Sand with Crushed Rock Fines in the Composition of Fine-Grained Concrete


 
 
 The expediency of replacing natural quartz Sands, whose reserves are gradually exhausted, by rock screenings as part of fine-grained concretes is shown. In particular, the characteristics of granite and quartzite crushing screenings in comparison with quartz river sand are presented, as well as the results of studying the strength and abrasion of the fine-grained concrete obtained. To exclude the effect of the grain composition on the properties of concrete, aggregate samples were pre-fractionated, and the conditions for producing concrete (cement consumption, water-cement ratio, concrete mix mobility) were the same. It was found that quartz sand having rounded grains with a relatively smooth surface promotes the formation of dense particle packing and increases the strength of fine-grained concrete by 9-14%, but at the same time reduces the abrasion of similar standard samples by 20-30% compared to screenings crushing of granite and quartzite. The maximum abrasion resistance showed concrete containing quartzite screening. Quartzite – metamorphic (metasomatic) dense rock crushing which produces angular particles with a rough surface. The absence of dense packaging reduces the compressive strength of concrete samples containing quartzite aggregate compared to quartz sand. At abrasion of similar samples in a thin layer the resistance to sliding of filler particles one relative to another increases. Therefore, when choosing crushed rock fines instead of natural quartz Sands, it is important to consider the purpose of the designed fine-grained concrete.
 Keywords: crushing screenings, quartz sand, granite, quartzite, fine-grained concrete, strength, abrasion
 
 

The effect of coarse aggregate characteristics on the shear behavior of reinforced concrete slender beams

This paper experimentally investigates the effects of the characteristics of coarse aggregate on the shear behavior of reinforced concrete slender beams. A total of eight reinforced concrete (RC) beams were fabricated with four types of coarse aggregate densities and mineralogy by utilizing limestone, quartizate, scoria, and steel slag aggregate. Beams were cast both with and without shear reinforcement and tested under three-point loading configuration. The experimental results indicated that all beams failed in a similar fashion, due to diagonal tension shear crack. The aggregates with high abrasion resistance resulted in a higher ultimate shear strength. The normalized shear strength for beams cast with similar compressive strength category generally followed an increasing trend with abrasion resistance and density (i.e., 7.9 for beams with limestone aggregate, 9.9 for quartzite aggregate, and 11.6 for steel slag aggregate). It was observed that the initial stiffness of the beams was independent of the aggregate type and was solely reliant on the concrete’s compressive strength. For the beams without shear reinforcement cast with similar compressive strength category (high-strength concrete), the peak and post-peak displacement capacity increased with the toughness of the coarse aggregates (limestone, the quartzite, and the steel slag). However, the variation in the peak displacement capacity for the beams with shear reinforcement was very insignificant, irrespective of the aggregate type. The experimental results in terms of the ultimate shear strength were validated against models proposed in the literature, including the recommended design equations of various codes of practices. Additionally, a shear strength model was proposed using the simplified ACI 318 [1] equation. The proposed model showed predictions that closely matched the experimental results.

Experimentally informed fracture modelling of interfacial transition zone at micro-scale

The aim of this work is to predict the micromechanical properties of interfacial transition zone (ITZ) by combining experimental and numerical approaches. In the experimental part, hardened cement paste (HCP) cantilevers (200 μm × 100 μm × 100 μm) attached to a quartzite aggregate were fabricated and tested using micro-dicing saw and nanoindenter, respectively. In the modelling, comparable digital specimens were produced by the X-ray computed tomography (XCT) and tested by a discrete lattice model. The fracture model was calibrated by the experimental load-displacement curves and can reproduce the experimental observations well. In the end, the calibrated model was used to predict the mechanical behaviour of ITZ under uniaxial tension, which can be further used as input for the multi-scale analysis of concrete.

IMPACT OF COARSE AGGREGATE ON COMPRESSIVE STRENGTH OF CONCRETE

Over one-third of the volume of concrete is occupied by coarse aggregate and any changes in coarse aggregate type can affect its strength and fracture properties. The paper examined the impact of coarse aggregates on compressive strength of concrete. Slump and compaction factor tests were conducted on the mixture of quartzite and crushed granite course aggregates, and quarry dust (fine aggregate). Nominal mix (1:2:3) was adopted and mix compositions were calculated by absolute weight method. Twelve (12) cubes (150x150mm) of each type of coarse aggregate were cast for 7, 14, 21, and 28 days to determine their compressive strengths. Quartzite was found to have the highest average compressive strength of 24.48N/mm2 with an average density of 2160kg/m3 , while compressive strength of crushed granite was 22.01N/mm2 with an average density of 2300kg/m3 on the 28 day of testing. Concrete made from granite had the highest workability, while concrete made from quartzite aggregate had the highest compressive strength. Densities and compressive strengths of the individual aggregates accounted for the variation in strengths of the concrete, due to differences in properties and strengths. In conclusion, the effect of any type of coarse aggregate on the compressive strength of concrete will be known and also enable contractors to determine the type of aggregate to be selected for a particular work.
 Keywords: Compaction factor test; slump test; strength; workability.

Effect of Elevated Temperature on the Residual Properties of Quartzite, Granite and Basalt Aggregate Concrete

In the present study, experimental investigations have been carried out to determine the effect of elevated temperature on the residual properties of quartzite, granite and basalt aggregate concrete mixes. Ultrasonic pulse velocity and unstressed residual compressive strength tests on cube specimens have been conducted at ambient and after single heating–cooling cycle of elevated temperature ranging from 200 to 600 °C. The relationship between ultrasonic pulse velocity and residual compressive strength of all concrete mixes have been developed. Scanning electron microscopy was also carried out to study micro structure of quartzite, granite and basalt aggregate concrete subjected to single heating–cooling cycle of elevated temperature. The results show that the residual compressive strength of quartzite aggregate concrete has been found higher than granite and basalt aggregate concrete at ambient and at all temperatures. It has also been found that the loss of strength in concrete is due to the development of micro-cracks result in failure of cement matrix and coarse aggregate bond. Further, the basalt aggregate concrete has been observed lower strength due to low affinity with Portland cements ascribed to its ferro-magnesium rich mineral composition.

SECONDARY MINERAL RESOURCES FOR REFRACTORY PRODUCTION. PART I. SILICA TECHNOLOGICAL MATERIALS

An option for the technological refractory raw materials chemical and mineral classification is proposed. Four largescale secondary man-made mineral formations of mostly siliceous composition are regarded in the article. The non-waste technology for the reject products handling which gives the enriched raw materials for preparation of the ZKV-97 quartzite aggregate, building rocks, gravel and sand was developed. The fitness was determined of the silica wastes fine-grained fraction (the concentration tailings) for the preparation of the molding materials, filter building materials, as well as for acting in the way of the raw materials for container glass and other items. It was shown that the using molding sand's regeneration products can be applied for the high quality coke silica bricks preparation. The integrated study of micro silica was carried out and on base of this investigation the promising trends of its utilization were proposed. Ill. 5. Ref. 9. Tab. 10.

Process Behaviour of Super-hard Cutting Materials for Machining Mineral Cast

Increasing requirements on the economic and energy efficiency as well as the machining accuracy of manufacturing processes lead to the use of innovative materials and production technologies. By deploying mineral casting as a construction material for machine beds the primary energy demand and manufacturing costs on the one hand can be reduced significantly. On the other hand the mechanical and thermal properties of mineral cast allow for an increase in process reliability and productivity of highly dynamic manufacturing processes. However, the hardness and wear resistance of the quartzitic aggregates in the compound have an adverse effect on the machinability of mineral cast with geometrically defined cutting edges. High alternating mechanical loads and abrasive tool wear lead to short tool life and high manufacturing costs. Nevertheless, machining of mineral cast with geometrically defined cutting edges represents a key driver for the design and manufacturing of mineral cast components according to customer specific requirements. The Institute for Machine Tools and Factory Management (IWF) at the Technische Universität Berlin performed comprehensive cutting tests to analyze the general performance behavior of super-hard cutting materials in machining mineral cast. The studies show that the choice of cutting materials, the tool geometry and the process parameters strongly affect the process reliability of mineral cast machining. First requirements of a process-oriented tool design for the efficient machining of mineral cast have been developed.

Effect of type of aggregate on permanent deformation of bituminous concrete mixes

The physical properties and performance of hot mix asphalt are governed by the properties of the aggregate, properties of the asphalt binder and asphalt–aggregate interactions. The study is aimed to compare the behaviour of bitumen containing various type of modifiers [styrene-butadiene-styrene (SBS) and ethylene-vinyl-acetate (EVA)] and aggregates (acidic and basic characters) for preparing hot mix asphalt on permanent deformation. Rutting and static creep tests were performed on various mixes to evaluate permanent deformation. Dynamic shear rheometer was used to determine the rheological properties and hence rutting parameter (G*/Sinδ). The results indicate that polymer modification increased rutting resistance. Moreover, samples prepared with EVA are more resistant to deformation compared to those prepared with SBS. Mixes consisting of quartzite aggregate are likely to deform more compared to marble mixes, both for modified and unmodified bituminous mixes, but the recovery of quartzite mixes on removal of load is also more.

Quantification of coarse aggregate shape in concrete

The objective of this study is to choose indices for the characterization of aggregate form and angularity for large scale application. For this purpose, several parameters for aggregate form and angularity featured in previous research are presented. Then, based on these established parameters, 200 coarse quartzite aggregates are analyzed herein by using image processing technology. This paper also analyzes the statistical distributions of parameters for aggregate form and angularity as well as the correlation between form and angularity parameters. It was determined that the parameters for form or angularity of coarse aggregates could be fitted by either normal distribution or log-normal distribution at a 95% confidence level. Some of the form parameters were influenced by changes in angularity characteristics, while aspect ratio and angularity using outline slope, area ratio and radius angularity index, and aspect ratio and angularity index were independent of each other, respectively; and consequently, the independent parameters could be used to quantify the aggregate form and angularity for the purpose to study the influence of aggregate shape on the mechanical behavior of concrete. Furthermore, results from this study’s in-depth investigations showed that the aspect ratio and the angularity index can further understanding of the effects of coarse aggregates form and angularity on concrete mechanical properties, respectively. Finally, coarse aggregates with the same content, type and surfaces texture, but different aspect ratios and angularity indices were used to study the influence of coarse aggregate form and angularity on the behavior of concrete. It was revealed that the splitting tensile strength of concrete increased with increases in the aspect ratio or angularity index of coarse aggregates.