Aggregate Abrasion Research Articles

Enhancing durability and strength of concrete through an innovative abrasion and cement slurry treatment of recycled concrete aggregates

The increasing demand for sustainable construction materials has driven significant interest in utilizing recycled concrete aggregates (RCA). However, the mechanical performance and durability of RCA are often compromised due to the presence of residual mortar. This study explores an innovative surface treatment approach combining abrasion and cement slurry coating to improve the properties of RCA and enhance the performance of recycled aggregate concrete (RAC). Recycled concrete aggregates were subjected to mechanical abrasion, followed by a cement slurry coating, resulting in the production of Surface-Treated Recycled Concrete Aggregates (STRCA). The study evaluates the impact of STRCA on the compressive strength, drying shrinkage, electrical resistivity, and chloride ion penetration resistance of concrete mixes with varying replacement ratios (25 %, 50 %, 75 %, and 100 %). Results revealed that the water absorption of RCA was significantly reduced from 5.35 % to 2.61 % following the treatment. STRCA 25 and STRCA 50 mixtures exhibited compressive strength increases of 30.16 % and 18.99 % at 7 days, and 29.37 % and 17.13 % at 28 days, respectively. Higher replacement levels (STRCA 75 and STRCA 100) resulted in strength reductions, with 3.91 % and 16.64 % decreases at 7 days. Drying shrinkage increased progressively with higher RCA content, showing 1.72 %, 10.91 %, 25.86 %, and 38.79 % increases at 28 days for STRCA 25, STRCA 50, STRCA 75, and STRCA 100, respectively. Electrical resistivity improved for lower replacement levels, with STRCA 25 showing a 3.41 % increase at 28 days, while STRCA 100 exhibited a 26.25 % reduction. The rapid chloride penetration test results showed that STRCA 100 had the highest resistance to chloride ion penetration, with a 22.72 % and 28.69 % increase in passed charge at 28 and 56 days, respectively, compared to the reference concrete. The findings indicate that surface-treated RCA can enhance the mechanical and durability properties of concrete, especially at lower replacement levels, making it a viable option for sustainable construction.

Comparative Analysis of the Strength of Concretes Made from Different Aggregates

The paper aimed to explore the replacement of river sand in concrete with iron fillings and sawdust at various percentages (10%, 20%, and 30%). The study used a 1:2:4 mix design and a water-cement ratio of 0.5. Wooden square cubes of dimensions 100 x 100 x 100 mm were employed, resulting in 42 concrete cubes. Tests were conducted to assess particle size distribution, specific gravity, bulk density, aggregate impact value, aggregate abrasion value, and compressive strength at 7th and 28th days of curing. Notably, after 7 days, compressive strength results showed that concrete with a 10% iron fillings replacement (18.5 N/mm²) had a higher average strength than concrete with 100% river sand (17.6 N/mm²). However, as the percentage of iron fillings increased to 20% (9.8 N/mm²) and 30% (7.1N/mm²), the compressive strength decreased. On the other hand, concrete with sawdust replacements at 10% (3.7 N/mm²), 20% (1.4 N/mm²), and 30% (0.5 N/mm²) exhibited significantly lower load-bearing capacity. These trends persisted at the 28th day, with the compressive strength decreasing with increasing percentages of iron fillings (10%: 20.3 N/mm², 20%: 11.2 N/mm², 30%: 11.6 N/mm²) and sawdust (10%: 3.4 N/mm², 20%: 2.3 N/mm², 30%: 1.4 N/mm²). The findings suggest that a low percentage of iron fillings can be used in combination with river sand to maintain load-bearing capacity, but sawdust or wood particles should be avoided as they adversely affect compressive strength. This research contributes valuable insights into the use of these materials in concrete mixtures.

Characterization of heat-processed artificial lightweight aggregates from polyethylene terephthalate plastic waste

Plastic waste is an undeniable source of pollution that threatens the existence of the earth’s flora and fauna. The bulk of plastic waste generated globally does not go through the proper methods of disposal but is carelessly discarded into the aquatic or terrestrial environment. Current recycling efforts are largely inadequate and disposal in landfills is still fraught with environmental and land use challenges. The proper disposal of plastic waste, as well as mitigating the environmental, social, and health impacts of extracting natural aggregates can be achieved by incorporating plastic waste as aggregates in the construction industry. This paper presents a characterization of aggregates manufactured from polyethylene terephthalate plastic waste using thermal/mechanical methods. From the cost analysis, 24,341.67 Ugx (6.09 USD) was spent to produce 1 kg of PET aggregates. Morphological, intrinsic and mechanical characteristics of the produced aggregates were established using standard procedures and equipment. The results of morphological characterization indicate an irregular shaped aggregate with smooth surface, a dense graded aggregate with a fineness modulus of 4.25, flakiness index of 26%, elongation index of 16% and particle index of 13. Intrinsic characterization yielded particle density of 1330 kg/m3, bulk density of coarse aggregates of 715 kg/m3 and water absorption of 0.445%. Mechanical characteristics of aggregates were evaluated, with compressive strength of 50Mpa, Aggregate Crushing Value of 37%, Ten Percent Fines Value of 71KN, Aggregate Impact Value of 24% and Aggregate Abrasion Value of 20%. The characteristics of PET aggregates confirm their suitability for application in structural lightweight concrete and rigid pavement. The produced PET aggregates can be considered in mix design as a total or partial replacement of natural aggregates in concrete.

Performance evaluation of flexible pavement using polyethylene terephthalate (PET)

In this study, the benefits and feasibility of incorporating Polyethylene Terephthalate (PET) into Flexible pavement were evaluated. The study aims to identify new ideas on recycling plastic wastes and thereby improving overall sustainability. The Samples were prepared by adding PET with an increasing concentration level along with optimum asphalt content with a percentage by weight of 3.5%, 4.0%, 4.5%, 5.0%, 5.5% and 6%. Multiple tests were conducted on Natural aggregates including Resistance to degradation of aggregates by Abrasion and Impact, Specific Gravity and Abrasion of coarse aggregates, and Impact Value of Aggregates. Similarly, the tests conducted on asphalt include the specific gravity of semi-solid bituminous material, the ductility of bituminous material, the flash point and softening point of asphalt, and the penetration grade of bituminous material. Rutting potential of the optimum asphalt, Plastic mix Was evaluated by increasing the frequency of load cycles from 0 to 5000 cycles. Furthermore, the effect of asphalt and plastic content on the density, Flow, voids, and stability were also analysed. It was found that the addition of PET resulted in improved stability by more than 50% specifically 52%, while 70% improvement was observed in flow characteristics of Hot Mix Asphalt. However, a slight change in density was observed. The sample also showed a reduction in rut depth by more than 40% of the mix.

Relationship Between Abrasion, Fragmentation and Thermal Weathering Resistance of Aggregates: Regression and Artificial Neural Network Analyses

Relationship Between Abrasion, Fragmentation and Thermal Weathering Resistance of Aggregates: Regression and Artificial Neural Network Analyses

Evaluation of Concrete Abrasion Using Traditional and High-Speed Underwater Methods

With the increasing height of new dams, the number of high-water-head and high-flow spillway buildings is gradually increasing, and concretes are required to have better abrasion resistance. Current standards offer a method for evaluating the abrasion resistance of concrete, but when evaluating the abrasion resistance of high-performance concretes, it is necessary to extend the test time to more than 120 h. In this study, an improved way of the current code-specified underwater method was proposed to shorten the testing time, called the high-speed underwater method (HSUM), and the test results of the two methods were evaluated using three-dimensional (3D) laser-scanning technology. It was found that the abrasion efficiency of the HSUM was about twice as much as that of the code-specified method. HSUM resulted in a significant acceleration of the concrete coarse aggregate abrasion process. The average abrasion depth of concrete was between 0 and 6.5 mm (HSUM after 15 h and code method after 30 h), and the abrasion mainly occurred on the surface of slurry, when the abrasion resistance of concrete was obviously affected by the strength and volume of slurry. When the average abrasion depth of concrete exceeded 6.5 mm, it entered the aggregate abrasion stage, and its abrasion resistance was influenced by the aggregate hardness and aggregate content, and the correlation with the slurry strength decreases. The surface roughness parameters Sq and Sa of HSUM concrete increase significantly compared with the code method. HSUM allows for a reduction in experimental time and high performance in evaluating the abrasion resistance of high-performance concretes or concretes with special aggregates (high-strength granite aggregates and cast stone aggregates).

Evaluation of Limestone from Cretaceous to Tertiary age in Kurdistan Region of Iraq for Heavy Duty Road Pavement

Aggregates have an important role in the development and quality of Hot Mix Asphalt pavement, Engineers prefer using different types of acidic aggregates as a dominant road pavement mixture. This study is focused on using a basic aggregate, for this purpose limestone is used as a replacement to sandstone and gravel in the Hot Mix Asphalt for base and binder course, due to its rough, tough, durable and stable properties, that adheres well with the binder due to its hydrophobic properties. A petrographic study and chemical analysis by XRF method was carried out for better determining the mineralogical and chemical contents. Los Angeles Abrasion test carried out for measuring abrasion of the limestone aggregates in Kurdistan Region Iraq from Cretaceous-Tertiary age in different sources of the Shiranish Formation in Pirat, Harir, and Safin, Aqra-Bekhme in Shakrok, the Pila Spi Formation in Pirmam, Khurmala Formation in Safin, the Euphrates Formation in North Qarachugh, and the Qamchuqa Formation in Bana Bawi, while the only last four formations selected for Marshal test depending on wear <45% according to Iraqi SORB, 2003 standards. The soundness test results showed that the selected four samples are within the required specifications. The aggregate-asphalt mixture molds were prepared with the optimum binder content of 4.7%, for the Marshall stability test, which revealed that all the selected four samples are suitable as a heavy-duty pavestone for the base and binder course, with BQ and Pm showed optimum stability results.

Experimental Study of Concrete Making Using Recycled Coarse Aggregate

Concrete is a form of construction in the form of a composite material consisting of a mixture of fine aggregate, coarse aggregate, cement, and water. However, in certain cases, the concrete application is often a problem, especially the lack of a minimal amount of coarse aggregate material, increasing material prices. Recycled concrete aggregate (RCA) is an embodiment of concrete composed of recycled materials. Recycled material is obtained from fragments or remnants of the demolition of unused concrete. The method used to make concrete from the constituent materials using concrete waste as coarse aggregate per the rules of science is experimental. The tests are the aggregate moisture content test, the mud content test, the coarse aggregate abrasion test, the slump test, and the concrete compressive strength test at 28 days of treatment. The compressive strength results showed that the normal concrete sample could reach FC 18.53 MPa. The concrete sample using recycled coarse aggregate reached FC 23.79 MPa, so using recycled materials for manufacturing concrete can achieve the planned target

Effect of morphology characteristics on the polishing resistance of coarse aggregates on asphalt pavement

Skid resistance performance of asphalt pavement is an important factor affecting the traffic safety. The long-term skid resistance performance of asphalt pavement depends on abrasion and polish resistance of aggregates. However, the mechanical properties and surface morphological characteristics of aggregates not only affect the road bearing capacity, but also impact the long-term abrasion and polish resistance of asphalt pavement. In this study, the mechanical properties of limestone, basalt, granite and 88 # calcined bauxite were investigated. The macro morphology characteristic parameters (MACP) of coarse aggregates were obtained by Image Pro Plus (IPP) software analysis with strong applicability, and the distribution models and characteristics were further analyzed. In order to present quantitatively the dynamic change process of the macro and micro morphology characteristics of coarse aggregates with the polished stone value (PSV) during the polishing process, a long-term polishing test was carried out on the coarse aggregates. The MACP and micro morphology characteristic parameters (MICP) of coarse aggregates were obtained by the IPP analysis and three-dimensional laser microscope. The grey relation entropy analysis method was used to analyze the correlation degree between morphological characteristic parameters and PSV. The results show that the contents of corundum and mullite in 88 # calcined bauxite are 85.2% and 14.8% severally. Corundum and mullite have the highest Mohs hardness, 9 and 6 respectively. The IPP analysis is suitable for quickly obtaining the MACP of coarse aggregates, and the MACP distribution of four kinds of coarse aggregates satisfies well normal distribution. In addition, in the process of PSV attenuation, the grey entropy correlation coefficients between PSV and fractal dimension, Rq are the highest, 0.9037 and 0.8882 respectively. The fractal dimension of MACP and Rq of MICP are selected as the main various indexes. Meanwhile, the average correlation coefficients of fractal dimension, Rq and PSV are 0.9589 and 0.9809 separately. Therefore, the fractal dimension and Rq are proposed to evaluate the long-term polishing resistance performance of coarse aggregates, and to provide useful references for the long-term skid resistance modeling of durable asphalt pavement.

Soil aggregate stability and its response to overland flow in successive Eucalyptus plantations in subtropical China

Soil aggregates constitute the basic units of the soil structure, and soil aggregate stability is an important indicator of soil erodibility. Successive planting of fast-growing plantations can change the erosion resistance of the soil under rainfall conditions. Pure Eucalyptus plantations in this study (first- to fourth-generations, i.e., I, II, III, and IV, respectively) were investigated. The stability and abrasion characteristics of soil aggregates were analyzed by the wet sieving method, the Le Bissonnais (LB) method and a slope flow scouring experiment. With an increase in successive generations of Eucalyptus, the soil bulk density increased, and the saturated water content, porosity, organic matter and Iron, Aluminum and Manganese (Fe-Al-Mn) oxide contents decreased. Additionally, the wet sieving results showed that the first- and second-generations had higher macroaggregate content than the fourth generation. The mean weight diameter (MWD) values decreased with the number of planting significantly. Based on fast wetting (FW), slow wetting (SW) and mechanical breakdown by shaking after pre-wetting (WS), the aggregate stability was ranked in a decreasing order as MWDSW > MWDWS > MWDFW. The relative dissipation index (RSI) and mechanical crushing index (RMI) increased with increasing number of planting generations. Aggregate stability was significantly negatively correlated with the soil bulk density and was significantly positively correlated with the organic matter and Fe-Mn oxide contents. The extent of aggregate abrasion (Wr/Wi) values and MWD values decreased with increasing scouring distance and slope gradient during the transport process. The α and Wr/Wi values of the scoured aggregates were significantly correlated with aggregate stability. Hence, with successive planting of Eucalyptus, the soil aggregate stability decreased, and the soil was prone to erosion when subjected to slope flow.

Retraction Note: Prediction of aggregate modified index (AMI) using geomechanical properties of limestones

Limestone aggregates are considered as construction materials with special suitability for use as a part of base courses, asphalt and Portland cement concrete. The suitability of aggregates for different applications is determined by aggregate parameters including the Los Angeles aggregate abrasion value (LAAV), aggregate impact value (AIV), and aggregate crushing value (ACV). In this paper, a combination of all these parameters is presented as an aggregate index (AI); Hamedan Limestones were classified based on this new index. The physico-mechanical properties of aggregates can also be used to evaluate their suitability for any specific engineering application; therefore, these properties of rock samples were measured. The AI was modified using p-wave velocity parameters, and changed into an aggregate modified index (AI/V p = AMI). Statistical analyses, including simple and multiple regressions, were applied to offer some rational approaches and identify those physico-mechanical parameters that are more appropriate for prediction of AMI. Consequently, based on these analyses, p-wave velocity, uniaxial compressive strength, dry density and Brazilian tensile strength parameters show significant correlations with AMI at α-level = 0.1.

Influence of Aggregates on Stripping Behavior of Bituminous Mixes

Moisture damage leads to premature failure of flexible pavements. The removal of bituminous coating from aggregates lead to the disintegration of bituminous mixes and is known as stripping. Various mechanisms and factors have been identified to play a role in the process, properties of aggregates being one of the major factors. This study is an attempt to analyze the influence of chemical, mineralogical and physical properties of aggregates on the stripping propensity of the loose mix. For this purpose, aggregates are chosen from six different quarry sites with diverse chemical compositions used for construction and maintenance of a large network of roads. Stripping tests are thereafter conducted on the aggregates using different percentage of hydrated lime. The amount of hydrated lime required for the prevention of stripping for concerned aggregate sources is determined. The research leads to the findings that the presence of elements such as silicon and potassium leads to a decrease in bond strength whereas the presence of calcium, sodium, iron, magnesium and aluminium enhanced the bond strength. Statistical tools and techniques are used to verify the results. Comparatively softer aggregates showed lesser resistance to stripping which could be inferred from aggregate impact and Los Angeles abrasion tests. The findings of the study can be helpful in the selection of aggregates with different chemical content for bituminous road construction depending upon the sensitivity to stripping. Doi: 10.28991/cej-2021-03091671 Full Text: PDF

Appraisal of Suitability of the “Mista Ali Granite of Jos Plateau StateNigeria” as an Aggregate for Construction Material using Selected Testing Parameters

The appraisal of the suitability of some selected granite deposits for aggregate stone production within the basement complex of Mista Ali of Jos Plateau state for road construction was carried out. Aggregate samples obtained from the deposits were analyzed in the laboratory to determine their mechanical properties by a series of composite testing parameters using aggregate abrasion value (AAV), aggregate impact value (AIV), aggregate crushing value (ACV), specific gravity (SG) and water absorption (WA) as contained in BS812, and AASHTOT96-92. It was found out that the granite deposits possess certain desirable aesthetic and visual characteristics. Also, the percentage mineralogical compositions of the studied samples were examined. The results had shown that Jolex Construction (JC) Quarry site has a good percentage composition of orthoclase and plagioclase content which reduces the rate of wearing and tearing. The results of the laboratory analyses on the aggregate sample indicated that the technical features measured such as the strength, density, and water absorption capacity of the “Mista Ali granite deposits” at the Jolex construction Quarry site are suitable for aggregate stone for road construction when compared with the globally accepted standard. The result of the appraisal will be useful and serve as database to prospective investors in aggregate stone quarrying.

Physical, chemical, morphological and strength characteristics of steel slags in view of its potential application in geotechnical engineering

Utilization of steel slag for various applications reduces the land area used for its storage and the cost incurred in storing. It is economical by conserving the conventional natural materials, which are depleting due to excessive usage over years and also environment friendly. The present paper is on characterization and establishing the suitability of two steel slags for different applications. In this context physical, chemical, strength and morphological characteristics are determined and compared with the specific requirements. The strength and mechanical characteristics are studied in detail by performing the aggregate abrasion test, impact value test, water absorption, density, flakiness index, presence of clay particles and other soft fragments. The chemical composition and the shape parameters are also studied. The physical, mechanical, chemical and morphological parameter of the slags states the possible utilization of the material in various applications. Results from various tests, indicate that these slags can be utilized as railway ballasts, coarse aggregates in concrete, gabion and rip-rap stones.

Improvement and In-Situ Application of an Evaluation Method of Ballasted-Track Condition Using Digital 2-D Image Analysis

The advancement in digital image analysis methods has led to the development of various techniques, i.e., quantification of ballast gravel abrasion. In this study, the recognition rate of gravel aggregates has been significantly increased by improving the image analysis methods. The correlation between the track quality index (TQI), which is the standard deviation of vertical track irregularity and represents the condition of a high-speed railway, and the number of maintenance works was analyzed by performing an image analysis on the samples collected from various locations of a high-speed railway. The results revealed that roundness has the highest correlation with the TQI, whereas sphericity has the highest correlation with the number of maintenance works. The ballast replacement would be performed to improve maintenance efficiency if the abrasion of the ballast aggregates becomes approximately 10%.

Determination of the relationship between the Los Angeles abrasion values of aggregates and concrete strength using the Response Surface Methodology

The present study aims to determine the relationship between aggregate abrasion strength and concrete strength considering water-to-cement and aggregate-to-cement ratios. For this purpose, concrete mixtures with different water-to-cement ratios (0.38, 0.40, 0.42, 0.45, 0.50, 0.55 and 0.60) were prepared with different aggregate types (basalt, marble, limestone, and natural aggregates). Hardened concrete properties of the prepared specimens were determined. Also, the abrasion tests were performed for each aggregate used in the experiments to determine the Los Angeles abrasion values of the aggregates. Using the experimental data, the compressive strength and splitting tensile strength values of the concrete specimens with dimensionless parameters such as water-to-cement ratio, aggregate-to-cement ratio, and Los Angeles abrasion loss value were analyzed using the Response Surface Methodology. Thus, two new models were developed with a multi-purpose optimization method. The compressive strength and splitting tensile strength can be calculated with high accuracy for different mixture designs with these models using the aggregate abrasion loss value, water-to-cement ratio, and aggregate-to-cement ratio. In conclusion, savings in labor and time, and economic profit are expected by designing a concrete mixture in this way.

The Effect of The Aggregate Abrasion Value on The Aggregate Pore Content in The Base Layer above Base B

Campuran lapisan pondasi bawah base B yang baik mempunyai persyaratan untuk agregat yang digunakan yaitu nilai abrasi kecil dari 40%, nilai berat jenis agregat minimum 2,5 dan penyerapan air agregat maksimum 3%. Hal ini sebagai syarat untuk menghindari degradasi dan disintegrasi agregat serta penyerapan air yang baik pada saat pencampuran, penghamparan, pemadatan maupun pada saat melayani lalu lintas selama umur rencana. Penelitian bertujuan untuk mengetahui pengaruh nilai abrasi terhadap nilai penyerapan air rongga pada campuran lapisan pondasi bawah base B dengan menggunakan 3 jenis quarry agregat. Penelitian ini menggunakan alat Los Angeles dan analisa saringan. Berdasarkan hasil pengujian diperoleh nilai abrasi paling baik adalah agregat quarry Solok yaitu 17,5 %, kemudian agregat quarry Pangkalan yaitu 23,7 % dan nilai abrasi yang kurang baik agregat quarry Bangkinang yaitu 34,58. Nilai penyerapan air agregat quarry paling tinggi adalah quarry Bangkinang kemudian quarry Pangkalan, dan nilai penyerapan paling kecil adalah quarry Solok. Hasil dari penelitian ini diharapkan dapat membantu pihak yang berkompeten dalam memberikan rekomendasi penggunaan material berdasarkan nilai abrasi dan nilai penyerapan air agregat.

Effects of sediment load on the abrasion of soil aggregate and hydraulic parameters in experimental overland flow

The breakdown of soil aggregates under rainfall and their abrasion in overland flow are important processes in water erosion due to the production of more fine and transportable particles and, the subsequent significant effect on the erosion intensity. Currently, little is known about the effects of sediment load on the soil aggregate abrasion and the relationship of this abrasion with some related hydraulic parameters. Here, the potential effects of sediment load on soil aggregate abrasion and hydraulic parameters in overland flow were investigated through a series of experiments in a 3.8-m-long hydraulic flume at the slope gradients of 8.7 and 26.8%, unit flow discharges from 2×10−3 to 6×10−3 m2 s−1, and the sediment concentration from 0 to 110 kg m−3. All the aggregates from Ultisols developed Quaternary red clay, Central China. The results indicated that discharge had the most significant (P>0.01) effect on the aggregates abrasion with the contributions of 58.76 and 60.34%, followed by sediment feed rate, with contributions of 39.66 and 34.12% at the slope gradients of 8.7 and 26.8%, respectively. The abrasion degree of aggregates was found to increase as a power function of the sediment concentration. Meanwhile, the flow depth, friction factor, and shear stress increased as a power function along with the increase of sediment concentration at different slope gradients and discharges. Reynolds number was obviously affected by sediment concentration and it decreased as sediment concentration increased. The ratio of the residual weight to the initial weight of soil aggregates (Wr/Wi) was found to increase as the linear function with an increasing flow depth (P=0.008) or Reynolds number (P=0.002) in the sediment-laden flow. The Wr/Wi values followed a power function decrease with increasing friction factor or shear stress in the sediment-laden flow, indicating that friction factor is the best hydraulic parameter for prediction of soil aggregate abrasion under different sediment load conditions. The information regarding the soil aggregate abrasion under various sediment load conditions can facilitate soil process-based erosion modeling.

Characterization of Classified Indian Reclaimed Asphalt Pavement RAP Aggregate Impact Value and Aggregate Abrasion Value of Rap Aggregates

Reuse of existing deteriorated bituminous pavement material in construction and maintenance of flexible pavement is called recycling of bituminous pavement. Removed and reprocessed deteriorated pavement material which is recycled is termed as Reclaimed asphalt pavement (RAP). In India during construction of flexible pavement different types of bituminous layers are in practice depending upon CBR of sub-grade and traffic count i.e. CVPD of the road stretch. Depending upon types of bituminous layer i.e. PC Seal Coat, Bituminous Macadam(BM), Dense grade bituminous Macadam (DBM), Semi Dense Bituminous Concrete (SDBC) or Bituminous Concrete(BC) Reclaimed Asphalt Pavement can classified in different groups These classified RAP groups materials will have different characteristics i.e. Rap aggregates and Recovered bitumen of different group of RAP will have different characteristics. In this study characterization of RAP limited to Aggregate Impact Value (AIV) and Aggregate Abrasion Value (AAV)of RAP aggregates of RAP classified in different groups. Results of this study will be compared to standard value of AIV and AAV required for bituminous construction to predict that RAP aggregates are suitable or not for use in bituminous mixes.

Strength Development and Durability of Concrete Containing Recycled Roof Tile Aggregate

The use of recycled aggregate in new concrete has often been limited due to concerns over their quality and structural performance. This research aims to investigate the physical properties of recycled roof tile aggregate and its suitability for concrete production. Physical properties of recycled roof tile aggregate are compared to normal crushed stone aggregate. Effects of recycled roof tile aggregates on strength and durability of recycled roof tile concrete was compared with normal aggregate concrete using mechanical properties and durability tests. The experimental results showed that high water absorption and low strength of aggregate have a great effect on the workability and strength of the concrete containing recycled roof tile aggregate. Aggregate density, water absorption, crushing value and abrasion value of the recycled roof tile aggregate were found to be lower than crushed stone aggregate and concrete containing recycled roof tile aggregate had low strength and slow strength development. Similar durability performance of recycled roof tile aggregate concrete and normal aggregate concrete was observed except when exposed to freezing and thawing.