Aggregate Impact Value Research Articles

Strength and durability status of the Fagfog Quarzite from the Lower Nawakot Group, central Nepal Lesser Himalaya

Railways have played vital role in the development of many countries worldwide. Government of Nepal has already planned to establish various national and international railway networks within the nation. A substantial quantity of durable rock ballasts is required for building a sustainable railway network. Quartzites from central Nepal Lesser Himalaya can be a promising source to fulfill this requirement. Therefore, the quartzites from the stratigraphic unit Fagfog Quartzites of the Lower Nawakot Group located in Dhading District along the Kalu Pandey Highway have been assessed to determine physical, strength and durability characteristics of the ballasts. All quartzite ballasts obtained from the bedrocks were of Precambrian, medium-grained, bladed to prolate shaped, white to brownish white, crushed quartzites. Dry density and water absorption were respectively 2336-2641 kg/m3 and 0-2.5%. The bulk density varies from 1204 and 1387 kg/m3. Point load strength index varies from 2.04 to 11.55 MPa (medium strong to extremely strong). Aggregate Impact Value (AIV) and Aggregate Crushing Value (ACV) ranges from 14.85 to 22.77% and 15.51 to 22.17% respectively. Some 7% results of AIV and 20% of ACV results exceeded the established limiting value of 22%. The slake durability index (Id5) ranges from 95.19 and 99.11%, whereas Id2 ranged between 96.94 and 100%, which shows that 80% of the samples have very high slake durability whereas remaining 20% exhibit high slake durability. There was no significant change in slake durability index from the second to the fifth cycles. Los Angeles Abrasion Value (LAAV) varies from 12.07 to 31.34% and Sulphate Soundness Value (SSV) varies within a limited range of 0.20 and 4.59%. Conclusively, the comprehensive evaluation suggests that the quartzite ballast from the Fagfog Quartzite source display favourable qualities in terms of point load, crushing and impact strengths and durable against abrasion, slaking and frosting. Thus, the quartzites from Fagfog Quartzite hold significant potential as a suitable rock type for railway track ballasts.

Thermo-mechanical treatment as an upcycling strategy for mixed recycled aggregate

The study investigates thermo-mechanical treatment for mixed recycled aggregates (MRA). Six treated aggregates were prepared by heating MRA between 300 °C and 800 °C, followed by 100 abrasion cycles. The thermo-mechanical treatment causes loss in the adhered mortar and improves aggregate crushing, impact and abrasion value up to 700 °C. Concrete prepared with MRA treated at 700 °C, as compared to natural aggregates, shows higher workability (166.67%) and comparable mechanical strength, i.e., compressive (93.72%), flexural (99.94%) and split tensile (97.87%). The sustainability assessment shows that treating MRA with renewable energy can have lower economic costs (89.36%) and carbon emissions (58.05%) than manufacturing natural aggregates.

Rock Aggregate Size Influence on Physical Degradation of Laminate Sedimentary Rocks in Flexible Pavement

Rock aggregates are the most fundamental material of highways, railroads, and other construction activities. Degradation of aggregate is the disintegration of aggregate due to the wheel load and moisture saturation causing loss of support in unbound granular layer and reduction of drainage in pavement materials. Sedimentary rocks from different quarries were evaluated to determine the influence of aggregate size on the degradation of materials. This study is to find out the effect of size on physical parameters of aggregate used in flexible and rigid pavement. The performance of river rock and crushed rock physical properties has been tested and compared. In order to determine the effect of aggregate size on their degradation properties, different sieve ranges were selected. The sieve sizes are graded into four categories according to Indian Standard sieve: R1 (20 mm-16 mm), R2 (16 mm-12.5 mm), R3 (12.5 mm-10 mm), and R4 (10 mm-4.75 mm) for degradation test such as, aggregate impact value (AIV), aggregate crushing value (ACV), water absorption (WA) and weathering test such as soundness and slake durability. It is observed that the larger size of aggregate has given better resistance against impact load, abrasion, weathering action and water absorption compare to smaller size over the same volume of rock. The rate at which aggregate degradation occurs is influenced by size. Along with the wheel load, environmental factors including moisture and temperature changes are the primary causes of the early degradation of aggregate. The river rock has a better resistance against degradation and weathering action as it has lesser lamination (a small scale sequence of fine rock layer). Adoption of larger size aggregate in the pavement base course is suggested to withstand the effect of environmental action and wheel load, especially on the friable and quickly disintegrated rock. Arating value, rating index and regression equation have been developed for aggregate degradation. Keywords: Particle Size, Properties of Rock, Weathering, Slake Durability, Degradation Index

Çimento Hamuruyla Kaplanmış Pomza Agregalarının Su Emme ve Darbe Dayanımı Performanslarının İncelenmesi

Pumice aggregate, which has high reserves in our country, is used in the production of lightweight concrete, however, it is not preferred as a structural lightweight concrete since its low mechanical properties. The mechanical properties of pumice aggregates can be improved by coating their surfaces. In this way, the coated pumice aggregates can be used to produce lightweight concrete. This study investigated the coating potential of Kayseri and Ahlat pumice aggregates with cement paste. The flow diameter, marsh funnel, and 28-day flexural and compressive strength values of the cement paste 0.55-0.50 w/b ratio and 0.35-0.30 w/b ratio with 1.5% plasticizer admixture were determined. At the end of 28-day curing, the Coating effectiveness of the produced samples was investigated via optical microscope, aggregate impact value, water absorption, and unit weights, and comparisons were made with uncoated aggregates. After coating, it was determined that Ahlat and Kayseri pumice aggregates were crushed by 11% and 18%, considering the impact strength result, moreover a decrease in water absorption was obtained by 50.49% and 78.32%, respectively. As a result, the water absorption values of the coated pumice aggregates decreased, and the aggregate impact values increased compared to the uncoated pumice aggregates.

Effect of Activated Lime and Kaolin as Partial Replacement for Cement in Concrete Structure

This research presents the effect of activated lime and activated kaolin as a cement replacement on the properties of concrete. A natural clay sample known as kaolin and lime was activated through thermal activation and used to partially replaced cement. %-¾ size aggregate was used in the casting of concrete cubes using 150mm x 150mm x 150mm for grades 20 and 25, and 150mm x 150mm x 150mm mould using a mix ratio of 1:2:4 for grade 20 and 1:1 ½: 3 for grade 25. The water-cement ratio adopted for the experiment was 0.55. A preliminary laboratory investigation was conducted include; sieve analysis, bulk density, specific gravity, aggregate impact value (AIV), aggregate crushing value (ACV), flakiness test, and elongation test. Also setting time of cement and standard consistency test was carried out. A Different replacement was cast and cured for 7, 14, and 28 days, and crushed. The compressive strength was gotten and conclusion a drawn.

Machine learning models for predicting unconfined compressive strength: A case study for Precambrian basement complex rocks from Ado-Ekiti, Southwestern Nigeria

This study investigates the applicability of four distinct machine learning (ML) models – Random Forest (RF), Relevance Vector Machine (RVM), Support Vector Machine (SVM), and Artificial Neural Network (ANN) - for predicting the unconfined compressive strength (UCS) values of Precambrian basement rocks. The models employ input parameters such as rock aggregate index (Aggregate Crushing Value (ACV), Aggregate Impact Value (AIV), and Los Angeles Aggregate Value (LAAV)) and mechanical test index values (Schmidt Hammer Rebound Number (SHR) and Point Load Strength Index (IS(50)) for prediction purposes. Additionally, a multilinear regression (MLR) model was implemented to compare the predictive performance of the ML models against the traditional linear regression model. The developed models were validated using performance metrics such as Mean Absolute Error (MAE), Root Mean Squared Error (RMSE), and Adjusted R-Squared (Adj.R2). The Friedman statistical test was also employed to investigate the significance of the differences in the performance of the models. The results indicate that all the models performed well and showed better predictive performance compared to the MLR model during both the training and testing phases, except for the ANN model, which exhibited slightly poorer performance than the MLR model in the testing phase. However, the SVM model demonstrated the best predictive accuracy among all the models with MAE, RMSE, and Adj.R2 scores of 0.76 and 1.45; 1.16 and 1.8; 0.98 and 0.90, respectively, for the training and testing phases. The difference in the performance of the predictive models was statistically significant, as revealed by the Friedman statistical test. A feature importance analysis was conducted to verify the significance of each input parameter, revealing that all input features had a positive effect on the output of all the models. However, IS(50) had the most significant impact on the models.

Petrographic and geotechnical evaluation of Ogwashi-Asaba ferruginised sandstone, Niger Delta, as aggregates for construction

The need to reduce the high cost of long-distance haulage of aggregates has necessitated the search for suitable aggregates close to the construction site(s). The petrographic and geotechnical properties of Ogwashi-Asaba ferruginised sandstone were investigated to ascertain their utility potential. The petrographic, physical, and mechanical properties investigated include; the modal composition, texture, packing density, degree of interlocking of grains, specific gravity (SG), water absorption capacity (WAC), aggregate crushing, aggregate impact, and Los Angeles abrasion values. Which were determined according to BS and ASTM standards. The percentage of iron (Fe2O3) was determined by fusion inductively coupled plasma (FUS-ICP). The results show the mean value of quartz as 59.4%, sub-angular to angular shape, medium, medium-coarse, and coarse-grained with sutured, concavo-convex, and long contacts. The mean values for the S.G., WAC, ACU, AIV, and LAAV are 2.68, 4.80%, 53.76%, 41.99%, and 50.12% respectively, and 17.8% for Fe2O3. The medium-grained sandstone is preferred because of its relatively higher quartz percentage, more sutured contacts, and a greater degree of grains interlocking. Fe2O3 in sandstone has a strong negative correlation with AIV and ACV. This implies that Fe2O3 in sandstone will influence strength in sandstone thereby enhancing its utility potential. Though the ferruginised sandstone may be suitable as base course material in high-density traffic roads, it can be utilized as sub-grade and sub-base materials in low-density traffic roads.

Validity of the Lower Zab River Sediments for Road and Asphalt Works - Southwest of Kirkuk/Northern Iraq

In this study, a geotechnical assessment of gravel and sand deposits were conducted on both sides of the Lower Zab River in the southwest of Kirkuk Governorate/Northern Iraq. geologically the sediment related to Quaternary age and tectonically located at the unstable zone. 5 samples were collected from the study area for the purpose of conducting various geotechnical tests on them and their validity for road works to the sub-base layer and the base layer for asphalt works.
 The results of the physical tests were shown by grain size analysis of thes aggregates for the samples of the study area, and it was found that they are identical to class (A) According to the American Standard [1], and suitable for use in road works for the sub-base layer. The moisture ratio ranging between (1.95 - 4.26) %. The tests of flatness and elongation showed that the highest percentage of flat-shaped particles was (29%) and longitudinal-shaped particles (19%).
 The laboratory tests results showed the durability tests such as - Los Angeles test the highest percentage of weight loss was (20.06%), and thus it is valid according to the Iraqi Standard Specification [2] for use in road works. the highest result of test the aggregate impact value of samples is 7.8%, It conforms to the requirements of specifications that must be provided for road works for a sub base layer. Accordingly it is valid for road works. It was found from Proctor test for (5) samples from the study area that the values of the maximum dry density ranged between (2.14-2.28 gm/cm3), and the values of the optimum moisture content ranged between (3.1-2.41%).
 An asphalt typical mixture was designed for the base layer from the aggregate of the first station S1 as represent station consisting of coarse crushed aggregate 12%, medium crushed aggregate 22%, fine crushed aggregate 20%, river sand 40% and the proportion of filler 6%. The results of the asphalt tests for the ideal station S1 showed that the ideal percentage of asphalt from the weight of the mixture in the asphalt mixture is 4.1, which is within the limits of the specification Roads and Bridges [3]. The percentage of asphalt to the weight of the aggregate after adding the ideal percentage of asphalt showed that its value was 4.3%, As for the stability test result (Marshall), it reached 11.4 kN, and the result of the creep test (Marshall) reached 2.9 mm, and the density was 2.362

Recycling of Contaminated Marine Sediment and Industrial By-Products through Combined Stabilization/Solidification and Granulation Treatment.

Stabilization/solidification (S/S) is becoming increasingly important, as it allows the remediation of contaminated sediments and their recovery into materials for civil engineering. This research proposes a cement-free cold granulation process for manufactured low-cost aggregates from marine sediments contaminated with organic compounds and metals. After the chemo-physical characterization of the study materials, two mix designs were prepared in a rotary plate granulator by adding two industrial by-products as geopolymer precursors, coal fly ash (CFA) and Blast Furnace Slag (BFS), but also alkaline activation solutions, water, and a fluidizer. The results indicated that sediments treated with mix 1 (i.e., with a higher percentage of water and fluidifier) represent the optimal solution in terms of metal leachability. The metal leachability was strictly influenced by aggregates' porosity, density, and microstructure. The technical performance (such as the aggregate impact value > 30%) suggested the use of granules as lightweight aggregates for pavement construction. The results indicated that cold granulation represents a sustainable solution to recycling contaminated marine sediments, CFA, and BFS into lightweight artificial aggregates.

Petrographic and Physiomechanical Investigation of Late Cretaceous Kawagarh Formation Kahi Section, Nizampur Basin

The late Cretaceous Kawagarh Formation has been investigated in terms of field observation, and petrographic analysis, to understand the petrography and its impact on the geotechnical properties. The Kawagarh Formation is well exposed among the upper Indus Basin, and has been studied by various workers in different aspects. Kawagarh Formation exposed in Kahi section of Nizampur Basin has been selected in this study to know the behavior of carbonate rocks for engineering purposes. Lithologically, this formation is composed of thick to medium bedded, highly fractured limestone, marls, and dolomitic limestone which has undertaken diagenetic alteration including dolomite, calcite veins, and stylolites. Followed by petrographic analysis which reveals that the Kawagarh limestone is mostly fossiliferous comprised of a large number of planktonic foraminifera fossils like Globotruncana Hilli and Globotruncana Linneana fossils. Furthermore, to know the impact of petrographic minerals on engineering behavior, mechanical properties in terms of uniaxial compressive strength (UCS) and uniaxial tensile strength (UTS) were also computed by using a universal testing machine (UTM). The resultant mechanical values lie in the strong compressive strength and suggest their usage for various construction purposes. Aggregate degradation tests including water absorption, specific gravity, aggregate impact value, Los angles abrasion, and soundness was also computed according to the International standard organization, ASTM (American Society for testing materials) and British standard. The aggregate values of the Cretaceous Kawagarh Formation are within the defined standard limits and can be used as an aggregate source for different construction engineering projects.

Analyze the Geotechnical Properties of Aggregate in Al-Mahzam area and Evaluation of its Suitability for Using in road purposes

This research studies the geotechnical properties of the Quaternary deposits aggregate in Al-Mahzam area in Tikrit city/Salahadin governorate. Samples are collected from three sites on the western bank of Tigris River for studying the physical, mineralogical, chemical, strength and durability properties and evaluating its suitability for sub base in road works. The results for the physical tests through the grain size distribution test show that the aggregate is well graded and suitable to use in road works as sub base for class A. Specific gravity and density tests were carried on according to ASTM, D854,C127 Liquid limit value are (5.10, 2.2 and 4) % and the samples are non-plastic while the value of the elongation and flakiness index according to ISS, 45/1989 are (21.65, 16.04 and 15.85)% and (26.11, 28.65 and 36.00)% respectively.
 Mineral composition test of gravel particles revealed that carbonate gravel forming the high percentage of the mineral composition, chert and quartz, sandstone, igneous and metamorphic rocks respectively. Strength test for aggregate Impact Value were carried out according to ISS,47/1970 and B.S.812-112,1990 are (7.06,9.79 and 8.8)% which is classified to exceptionally strong which is specified that shall not exceed 30% for using in road works, and compression strength value which is derived from point load test are (197, 189.3 and 182.4) MPa. according to Hawkins classification is very strong. The durability test results represented by the loss angles test are (26.72, 26.18 and 29.55)% which is suitable for sub base road work, and the average of the soundness test results were ranges (0.62-3.54)% for coarse and fine aggregates which is within the specification and suitable to use the aggregate in roadwork as the sub base. For the chemical tests the values of organic matter, pH value, TDS and sulfate salts (gypsum %) are within the specification and suitable for using in sub base course for road

Investigation of influence factors and surface treatment on palm oil boiler ash (POBA) based geopolymer artificial aggregate: Impregnation vs. coating method

Producing man-made aggregates from industrial waste or biomass is feasible. Solid waste from the palm oil industry is a significant environmental problem requiring both immediate and long-term solutions. This study investigated the effect of influence factors of palm oil boiler ash (POBA)-based geopolymer aggregate based on its physico-mechanical, thermal, and characterization properties. The cold-bonding method was chosen due to its lower energy consumption. All POBA-based geopolymer aggregates had specific gravities below 2.0, classifying them as lightweight aggregates. Some ratios provide aggregate impact values (AIV) that are less than 30% and are characterised as strong aggregates. The overall thermal conductivity obtained from the POBA-based geopolymer is 0.161–0.243 W/m.K. The optimum ratio of POBA-based geopolymer aggregate microstructure had a denser and more complex structure. The high water absorption of the POBA-based geopolymer aggregate necessitated the development of additional surface treatment techniques, including vacuum impregnation and coating. The vacuum impregnation process with geopolymer enhanced aggregate characteristics. Microstructure analysis indicated that geopolymer had filled the voids and strengthen the matrix, as proven through Micro-XRF analysis. The properties of concrete made with treated POBA-based geopolymer aggregate can be used as a structural application.

Engineering Properties of Aggregates for Railway Ballast, Rapati Nadi, Central Nepal Sub-Himalaya

Nepal has proposed various railway projects, such as the East-West Railway, Kathmandu Metro Railway, and Raxaul-Kathmandu Railway. Good ballasts are always sought in the projects to diminish maintenance cost. Sediments from the Rapati Nadi (River) in central Nepal are among probable sources of ballasts as those sediments are rich in quartzite clasts. To meet the ballast requirements for railway projects, the study assessed the physical, mechanical and durability properties of alluvial deposit aggregates. The compositional analysis yielded maximum percentage of quartzite followed by sandstone and others. The aggregates yielded uniformity in gradation. Flakiness and Elongation Indices of the tested samples ranged from 11.18 to 24.10% and from 13.07 to 42.77%, respectively. Specific gravity exceeded 2.4. Aggregate Impact Value, Aggregate Crushing Value and Los Angeles Value of the tested samples were respectively 4.4-13.2%, 10.20-17.67% and 15.75-34.25%. Similarly, the point load strength index ranged from 3.69 to 6.57 MPa, and the Sodium Sulphate Soundness Values ranged from 0.96 to 2.06%. All the test results satisfied the conditions based on IS specification in the context of aggregate shape, crushing strength, impact strength, and durability against abrasion. When the results of different indices and values are rated based on their higher, intermediate and lower ranges, all the samples fall in the range of the high rating. Thus it shows suitability of aggregates of the Rapati Nadi and sediment aggregates deposited between Basantapur and Bastipur seem better compared to other locations.

A study on the applicability of scoria gravel an alternative base course material through blending with marble waste aggregate

This study aims to evaluate the applicability of Scoria gravel as an alternative base course material in flexible pavements through blending with marble waste aggregate (MWA) by modifying the physical and mechanical engineering properties of scoria. Non-Probabilistic sampling techniques and experimental methods were used. To achieve the objectives of the study, the laboratory tests were passed in three steps. First, the Engineering properties of materials were independently tested; the result proves the marginality of scoria gravel. Second, scoria gravel was mechanically stabilized by 20% percentages by weight increments of MWA. The obtained engineering properties test results at 20:80 Scoria to MWA mix ratios are 2.56%, 21.38%, 18.59%, 19.27%, 17.45%, 13.77%, Non-Plastic, 1.21%, and 73.4%, for Specific Gravity, Aggregate Crushing Value, Aggregate Impact Value, Loss Angeles Abrasion, Flakiness Index, Elongation Index, Atterberg's limit, Water Absorption, and California Bearing Ratio (CBR) respectively. These test results fulfilled the ERA standard specification for GB2 and GB3 base course materials. However, the CBR test results showed a failure to meet the standard spécification. Thus, 20:80 Scoria to MWA percentage by weight ratio was selected as a control mixture. So, Crushed Stone Aggregate was added at 5% percentage by weight to improve the CBR of scoria gravel. Therefore, the CBR value of 82.13% attained the ERA standard Specification limit for base course materials at 15:60:25 percentages by weight ratio of scoria gravel, MWA, and CSA respectively. Finally, Based on this study it was recommended to use scoria gravel as an alternative base course construction material, when it was found abundantly near construction vicinity.

THE COMPARATIVE EXPERIMENTAL STUDIES ON THE SUITABILITY OF CERAMIC WASTE AGGREGATE AND RECYCLED ASPHALT PAVEMENT AGGREGATE AS AN ALTERNATIVE FOR BASE COURSE MATERIAL

The study aimed to assess the suitability of ceramic waste aggregate and recycled asphalt pavement aggregate as an alternative for base course material. An experimental research design method and Non-Probability sampling techniques were used. The comparative analysis of ceramic waste aggregate and recycled asphalt pavement aggregate were blended with crushed stone aggregate at different proportions by weight and their laboratory result was compared with standard specifications. The study results shown that the aggregate crushing value (ACV) for neat Crushed stone aggregate (CSA) and Recycle asphalt pavement (RAP) are 19.20% and 8.20% respectively and the blended CSA with 10%, 20%, 30%, 40% and 50% of RAP were 18.20%, 16.4%, 15.90%, 14.40%, and 13.10% respectively. Similarly, a 24.32% - 12.06% for Los Angeles abrasion (LAA) and 18.50% - 12.60% for aggregate impact value (AIV) were found to the lower and higher value in the range of the test result. The CBR test for a different proportion of RAP (10% - 50%) blended with CSA was also conducted and an economically acceptable result of 104.20% was found at 30% RAP mix at 98% maximum dry density (MDD). Additionally, the California Bearing Ratio (CBR) test result for 100%RAP at 98%MDD was 49.10%. On the other hand, the experimental tests were conducted on different proportions of Ceramic West aggregate (CWA) (10%, 20%, 30%, 40%, and 50%) which satisfy the principal mechanical properties of aggregate materials. The ACV result for neat CWA is 26.70% while the blended CWA- CSA aggregate was tested with 10%, 20%, 30%, 40%, and 50% of CWA with its complement of CSA as indicated and at 20% CWA replacement of CSA test results were (21.60%, for ACV), (26.31% for LAA), (106.9 for CBR) and (20.60 for AIV). For this investigation an economically acceptable results were achieved by satisfying the Ethiopian road authority (ERA) standard specification limit at 20% CWA and 30% RAP blended with CSA for base course construction material.

Enhancement of mechanical properties of concrete with treated demolition waste aggregate

The utilization of recycled aggregate (RA) from the construction and demolition waste (C&DW) in civil engineering applications, has proven to be an eco-efficient environmentally friendly approach to overcome the current environmental concerns. Nevertheless, the poor quality of RA has limited its utilization in high-grade civil engineering applications. To maximize and promote the use of RA, it is essential that an appropriate process of treatment methods is included in the production of RA to improve its properties. This research aimed to examine the effects of various enhancement methods on the mechanical properties (consistency, compressive strength, flexural strength, tensile splitting strength, and elastic modulus) of recycled aggregate concrete (RAC). This research also included microstructure investigation using Scan Electron Microscopy (SEM) images. The enhancement methods used were treating RA by Soaking in Cement-Pulverized Fuel Ash-Silica Fume solution (SCP), Sand Envelope Mixing Approach (SE), and their combination (SCP + SE). The enhanced RACs showed an increased 28-day compressive strength of up to 46 MPa suitable for structural applications. The tensile splitting strength, flexural strength, and modulus elasticity values of the enhanced RACs were 10%, 16%, and 6% higher than that of the untreated RAC. The improved mechanical performance of the enhanced RAC was attributed to the strengthened interfacial transition zone, better overall interlocking of the treated RA with the new cement paste, filled-up pores and micro-cracks, reduced water absorption, and improved aggregate impact value. The SEM images for the enhanced RACs showed better-compacted microstructure, lesser pores and microcracks. The application of the proposed innovative regime of enhancement methods is anticipated to promote the use of RA in the construction industry and provide a better scientific understanding of the performance of concrete produced with 100% treated RA from the C&DW for structural applications.

Enhancing the aggregate impact value and water absorption of demolition waste coarse aggregates with various treatment methods

Recycled aggregate (RA) from construction and demolition waste can readily be used to replace natural aggregate in concrete. Nonetheless, the poor quality of RA adversely affects the properties of recycled aggregate concrete, limiting its use to only non-structural applications. This study examined the effects of various treatment methods by testing the aggregate impact value (AIV) and water absorption (WA) of recycled coarse aggregate before and after treatments as an indicator to examine the efficiency of these treatments. The results showed that the untreated RA achieved 17% and 6.1% for AIV and WA, respectively. Accelerated carbonation treatment at 50% CO2 concentration level for six days of CO2 exposure time achieved the best results among other carbonation conditions, showing 11% and 46% enhancements in the AIV and WA, respectively. The RA treated with cyclic limewater combined with accelerated carbonation exhibited better improvement in the AIV and WA compared to the sole use of accelerated carbonation treatment. Coating RA with cement-silica fume slurry at 0.1 mm coating thickness was found to be optimal, achieving 12% and 54% enhancements in the AIV and WA, respectively. Soaking RA in a 10% Portland cement - pulverized fuel ash - silica fume solution for 4 h was found to be optimal, recording enhancements of 13% and 54% in the AIV and the WA, respectively among other soaking solutions. Soaking RA in 5% sodium silicate – silica fume solution for 4 h was found to be optimal, obtaining 8% and 33% enhancements in the AIV and the WA, respectively. The treatment techniques proposed can be a powerful tool for promoting the use of RA in the construction industry.

Use of Municipal Solid Waste Incinerated Bottom Ash and Construction Demolition Waste in Pavement

Abstract: This study focuses on the introduction of a layer of municipal solid waste incinerated bottom ash, sewage sludge and construction and demolition waste and the effect of this layer on the settlement and strength of the pavement. The primary principal of this paper is to deal with the use of MSWI bottom ash in a sustainable manner. This paper investigates the validity of mix layer as an applicable conventional subgrade. The objective of the paper is to study the viability of the utilization of Construction Demolition Waste (CDW) for improving the performance of sub grade and sub-base layers in the road design. On this mixture, certain tests are conducted like Aggregate Impact Value Test, Crushing Value Test, Specific Gravity Test, and Loss Angeles Abrasion Test. The results are analysed and discussed for the use of CDW for enhancing the performance of sub grade and sub-base layers in the pavement. Keywords: Construction Demolition Waste, Municipal Solid Waste, Sub-base

Experimental Investigation to Find the Strength of Ballast

Although ballast is only part of the substructure, it plays an important role in keeping the railway track in position. But less attention has been given to the substructure because the properties of the substructure are more varies and difficult to define than those of the superstructure. Research about ballast behaviours still needs to be developed. Objective of this research is to use Los Angeles Abrasion (LAA) and Aggregate Impact Value (AIV) test to analyse the strength of nature rock (NR), slag (S) and their different combination. Four different types of samples have been prepared for testing. LAA and AIVtest has been performed to assess the strength of the ballast. Finally, the result shows that the combination of slag and nature rock showed good results, even not really significantly. The result for 25%NR+75%S (LAA test) and 1NR+2S (AIV test) is 7,41% and 6,02%, respectively.

Assessment of Geotechnical Properties of Laki Limestone for Coarse Aggregate, Nooriabad, Jamshoro Sindh, Pakistan

Present study is aimed at assessment of geotechnical properties of Laki limestone as coarse aggregate which is being quarried in Nooriabad area, Sindh, Pakistan. Coarse aggregate samples (n=20) of limestone were collected for the evaluation of physico-mechanical properties of the aggregate. Petrographic analysis revealed that the aggregate comprises of hard, compact, massive, crystalline and fossiliferous limestone. It is devoid of any reactive silica (chert, chalcedony) and other harmful constituents like clays or organic matter. Average values of specific gravity, absorption,bulk density, void content and combined index (EI + FI) of collected samples are 2.5, 2.1%, 1.54 g/cc, 38.55% and 13.04% respectively. The values of specific gravity (2.3-2.9), absorption (0-8%), bulk density (1.28 g/cc-1.92 g/cc) and void content (30%-45%) are varying within the range of normal weight aggregate as per American concrete institute (ACI)specifications. On the other hand, absorption values of aggregate samples are slightly higher (2.1%) than the reference range (2%) but meet other requirements. Mechanical properties including aggregate impact value (8.58%), aggregate crushing value (26.66%), Loss Angeles abrasion value (24.77%), sodium sulfate soundness (4.72%), water soluble sulfate (0.006%) and water soluble chloride (0.005%) are found to be within corresponding guidelines set by ASTM. On the other hand, average carbonate content is found to be 89.64% indicating that Laki limestone is of slightly low purity. Except absorption, all physical and mechanical properties lie within specified ranges. It is concluded that Laki limestone is suitable for use as road aggregate and concrete mix design.