scholarly journals Settlement Analysis of Recycled Concrete Fine Aggregate Blended Soils using Geostudio

2019 ◽  
Vol 9 (2) ◽  
pp. 3007-3010
Keyword(s):  
Recycled Concrete ◽  
Engineering Properties ◽  
Real Field ◽  
Fine Aggregate ◽  
Virgin Soil ◽  
Concrete Aggregates ◽  
Finite Element Software ◽  
Crushed Concrete ◽  
Fine Aggregates ◽  
Settlement Analysis

Crushed concrete (CC) is one of the most abundant waste materials generated from construction industry. This material is widely recycled and used in various applications like pavement, concrete aggregates and backfilling. Crushed concrete is mixed with any of virgin soil to increase the engineering properties of soil. In the present study, a sample of crushed concrete is collected from demolished buildings at Secunderabad and the material is segregated according to gradation for the present study. The index properties of crushed concrete like pH, specific gravity, water absorption, particle size distribution are obtained. Locally available soil is partially replaced i.e., 30%, 50%, and 70% with crushed concrete fine aggregates and its compaction characteristics and shear strength parameters are determined. In the continuation of the study, a numerical model is developed using a finite element software i.e GeoStudio Sigma/w. Mesh and boundary extent convergence studies are done for the model. The top 1m virgin soil is replaced with the mixture of CC and soils. Settlements for various percentages of CC and for different width of footing are obtained for a uniform stress of 200kPa. The stress is applied in 5 stages in order to simulate real field conditions. It was observed that 30% replacement of CC have given the least settlement for all widths of footing considered in the study

scholarly journals Slope Stability Analysis of Recycled Concrete Fine Aggregate Stabilized and Blended Soils

2020 ◽  
Vol 9 (5) ◽  
pp. 991-994
Keyword(s):  
Limit Equilibrium ◽  
Recycled Concrete ◽  
Engineering Properties ◽  
Cement Kiln ◽  
Concrete Aggregate ◽  
Fine Aggregate ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Fine Aggregates ◽  
Kiln Dust

Recycled concrete aggregate (RCA) is one of the major material generated from municipal soild waste industry. In the current study, recycled concrete aggregates are collected from the demolished building. The index and engineering properties of crushed concrete and locally available soil are determined. The study aims at effective reuse of demolition concrete waste as backfill of earth retaining walls. RCA passing through 4.75mm is stabilized by using Cement kiln dust (CKD) and Fly Ash (FA) in various proportions. Red soil is partially replaced by 30%, 50%, and 70% with recycled concrete fine aggregates. A numerical model is developed using limit equilibrium software i.e GeoStudio Slope/w. It is found that 15% CKD and 15% FA is optimum to stabilize the material. In case of blended soils, 30% replacement with RC-FA is found to be optimum

scholarly journals Effects of Slag Addition and Mechanical Pre-Processing on the Properties of Recycled Concrete in Terms of Compressive Strength and Workability

2021 ◽  
Vol 64 (1) ◽  
pp. 11-29
Author(s):  
Madumita Sadagopan ◽  
Katarina Malaga ◽  
Magnus Lundin ◽  
Agnes Nagy
Keyword(s):  
Compressive Strength ◽  
Concrete Strength ◽  
Reference Value ◽  
Recycled Concrete ◽  
Quality Improvements ◽  
Concrete Compressive Strength ◽  
Concrete Aggregates ◽  
Crushed Concrete ◽  
Fine Aggregates ◽  
Furnace Slag

Abstract Concrete waste as crushed concrete aggregates (CCA) in structural concrete prolongs the technical life of the reference concrete accomplishing closed loop recycling. CCA concrete reaches the reference concrete compressive strength and workability by the densification of CCA and cement paste. Our previous study demonstrates CCA densification by mechanical pre-processing, aggregate quality improvements discerned by increased packing density giving reference concrete strength and workability. This study addresses paste densification with blast furnace slag (GGBS) to replace 30 (wt.%) of Portland cement at reference concrete w/b ratio 0.5 and a lower w/b 0.42. Two CCA replacements are investigated: fine aggregates, CCA50; overall aggregate replacement, CCA100. Compressive strength results show that both CCA50, CCA100 mixes achieve reference values at w/b 0.42, only CCA100 achieves reference value at w/b 0.5 as a climate-optimized concrete. The CCA50 mix-w/b 0.5 reaches reference strength when paste densification by GGBS is combined with CCA densification from mechanical pre-processing of aggregates. The 7-day strength of CCA100 with GGBS increases by 11% by mixing with pre-soaked GGBS. Statistical analysis of CCA100 strength results shows significant improvements with GGBS compared to mechanical pre-processing. Significant improvements are possible in CCA50 mix for a combination of mechanical pre-processed aggregates and GGBS replacement.

Review of Studies concerning Effects of Unbound Crushed Concrete Bases on PCC Pavement Drainage

1996 ◽  
Vol 1519 (1) ◽  
pp. 51-58 ◽  
Author(s):  
Mark B. Snyder ◽  
James E. Bruinsma
Keyword(s):  
Drainage System ◽  
Field Studies ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Drainage Systems ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Crushed Concrete ◽  
Pavement Structures ◽  
Natural Aggregates

Recycled concrete aggregate (RCA) products are sometimes used as replacements for virgin aggregate products in concrete pavement structures. Recent concerns have centered on the deposit of RCA-associated fines and precipitate suspected of reducing the drainage capacity of RCA base layers and associated drainage systems. Environmental concerns have focused on the relatively high pH of the effluent produced by untreated RCA base layers. Several studies have examined these concerns and others; the results of some of these studies have not been published or publicized. The most relevant of these studies are summarized herein. These research efforts demonstrate that calcium-based compounds are present in most recycled concrete aggregates in quantities sufficient to be leached and precipitated in the presence of carbon dioxide. Precipitate potential appears to be related to the amount of freshly exposed cement paste surface. Thus, selective grading or blending with natural aggregates can reduce, but not eliminate, precipitate problems. It was also noted that insoluble, noncarbonate residue makes up a major portion of the materials found in and around pavement drainage systems. Washing the RCA products before using them in foundation layers appears to reduce the potential for accumulation of dust and other fines in the drainage system, but probably has little effect on precipitate potential. Field studies have shown that precipitate and insoluble materials can significantly reduce the permittivity of typical drainage fabrics but that attention to drainage design details can minimize the effects of these materials on pavement drainage.

scholarly journals Investigation of the Use of Recycled Concrete Aggregates Originating from a Single Ready-Mix Concrete Plant

2018 ◽  
Vol 8 (11) ◽  
pp. 2149 ◽  
Author(s):  
Eleftherios Anastasiou ◽  
Michail Papachristoforou ◽  
Dimitrios Anesiadis ◽  
Konstantinos Zafeiridis ◽  
Eirini-Chrysanthi Tsardaka
Keyword(s):  
Soil Stabilization ◽  
Coarse Fraction ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Hardened Concrete ◽  
Fine Aggregate ◽  
Waste Products ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Concrete Mixtures

The waste produced from ready-mixed concrete (RMC) industries poses an environmental challenge regarding recycling. Three different waste products form RMC plants were investigated for use as recycled aggregates in construction applications. Crushed hardened concrete from test specimens of at least 40 MPa compressive strength (HR) and crushed hardened concrete from returned concrete (CR) were tested for their suitability as concrete aggregates and then used as fine and coarse aggregate in new concrete mixtures. In addition, cement sludge fines (CSF) originating from the washing of concrete trucks were tested for their properties as filler for construction applications. Then, CSF was used at 10% and 20% replacement rates as a cement replacement for mortar production and as an additive for soil stabilization. The results show that, although there is some reduction in the properties of the resulting concrete, both HR and CR can be considered good-quality recycled aggregates, especially when the coarse fraction is used. Furthermore, HR performs considerably better than CR both as coarse and as fine aggregate. CSF seems to be a fine material with good properties as a filler, provided that it is properly crushed and sieved through a 75 μm sieve.

scholarly journals Utilization of Recycled Concrete Aggregates in Stone Mastic Asphalt Mixtures

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Mohammad Saeed Pourtahmasb ◽  
Mohamed Rehan Karim
Keyword(s):  
Design Method ◽  
Recycled Concrete ◽  
Engineering Properties ◽  
Partial Replacement ◽  
Concrete Aggregate ◽  
Recycled Concrete Aggregates ◽  
Material Recycling ◽  
Mastic Asphalt ◽  
Fine Aggregates ◽  
Stone Mastic Asphalt

Recycled concrete aggregate (RCA) is considered as one of the largest wastes in the entire world which is produced by demolishing concrete structures such as buildings, bridges, and dams. It is the intention of scientists and researchers, as well as people in authority, to explore waste material recycling for environmental and economic advantages. The current paper presents an experimental research on the feasibility of reusing RCA in stone mastic asphalt (SMA) mixtures as a partial replacement of coarse and fine aggregates. The engineering properties of SMA mixtures containing RCA have been evaluated for different percentages of binders based on the Marshall mix design method. The outcomes were statistically analyzed using two-factor analysis of variance (ANOVA). Test results revealed that the performance of SMA mixtures is affected by RCA due to higher porosity and absorption of RCA in comparison with virgin granite aggregates. However, the engineering properties of SMA mixtures containing a particular amount of RCA showed the acceptable trends and could satisfy the standard requirements. Moreover, to achieve desirable performance characteristics, more caution should be made on properties of SMA mixtures containing RCA.

COMPARISON OF RECYCLED GLASS AND RECYCLED CONCRETE AGGREGATES BEARING MORTAR MIXTURES EXPOSED TO HIGH TEMPERATURE, ABRASION AND DRYING

2018 ◽  
Vol 13 (4) ◽  
pp. 39-59 ◽  
Author(s):  
Ali Mardani-Aghabaglou ◽  
Ahsanollah Beglarigale ◽  
Halit Yazıcı ◽  
Kambiz Ramyar
Keyword(s):  
High Temperature ◽  
Abrasion Resistance ◽  
Drying Shrinkage ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Fine Aggregate ◽  
Concrete Aggregates ◽  
Recycled Concrete Aggregates ◽  
Recycled Glass ◽  
Durability Performance

In this study, the effects of recycled glass (RG) and recycled concrete (RC) fine aggregates on the drying-shrinkage, carbonation, high temperature and abrasion resistance of mortar mixtures were investigated comparatively. In addition, durability performance of the mortar mixtures was investigated through micro-structural analysis. For this purpose, 9 different mortar mixtures were prepared by replacing 25, 50, 75 and 100 wt.% of crushed-limestone fine aggregate with recycled glass and recycled concrete aggregates. Except for the abrasion resistance, the RG mixtures showed better durability performance than the control mixture. However, the RC mixtures containing more than 50% recycled aggregate showed lower performance than the control mixture.

scholarly journals Laboratory Investigation of Fatigue Characteristics of Asphalt Mixtures with Steel Slag Aggregates

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Hassan Ziari ◽  
Shams Nowbakht ◽  
Sajad Rezaei ◽  
Arash Mahboob
Keyword(s):  
Fatigue Life ◽  
Resilient Modulus ◽  
Steel Slag ◽  
Engineering Properties ◽  
Fine Aggregate ◽  
Coarse Aggregates ◽  
Fine Aggregates ◽  
Indirect Tensile ◽  
Fatigue Characteristics ◽  
Marshall Stability

There are many steel-manufacturing factories in Iran. All of their byproducts, steel slag, are dumped randomly in open areas, causing many environmentally hazardous problems. This research is intended to study the effectiveness of using steel slag aggregate (SSA) in improving the engineering properties, especially fatigue life of Asphalt Concrete (AC) produced with steel slag. The research started by evaluating the physical properties of the steel slag aggregate. Then the 13 types of mixes which contain steel slag in portion of fine aggregates or in portion of coarse aggregates or in all portions of aggregates were tested. The effectiveness of the SSA was judged by the improvement in Marshall stability, indirect tensile strength, resilient modulus, and fatigue life of the AC samples. It was found that replacing the 50% of the limestone coarse or fine aggregate by SSA improved the mechanical properties of the AC mixes.

scholarly journals Petrography of fine aggregates from Kaligandaki River, western Nepal: implication for assessment of deleterious constituents

1970 ◽  
Vol 14 ◽  
pp. 29-34
Author(s):  
Naresh Kazi Tamrakar
Keyword(s):  
Size Fraction ◽  
Lower Amount ◽  
Fine Aggregate ◽  
Concrete Aggregates ◽  
Rock Fragments ◽  
Fine Aggregates ◽  
Quartz Grains ◽  
River Banks

Seven fine aggregate samples from test pits driven at the river banks of the Kaligandaki River and banks of the contributingstreams around Kokethanti-Chhyo Bagar area were petrographically analysed as these will be used for concrete aggregates. Theaggregates had median grains size of 0.45-1.00 mm and were well graded. They were dominantly composed of carbonate rockfragments and the total QFL modes being Q14.81–28.87F0.63–4.58L66.55–84.15. All the samples were classified as medium-grainedcalc-lithic sands. Quartz grains were dominantly megaquartz. Some chert grains and few quartz grains occurring in siliceouslimestones were of microquartz.Considering deletereous constituents, the sample T1 had chert fragments. The sample T2 had high amount of micas suggestingits low workability. Silt/clay-grade size fraction was the deletereous material to all the samples and this fraction should be removedduring processing. The samples T2, T6 and T7 showed greater preferability among the samples as these had lower amount ofunsound rock fragments such as carbonaceous schists/phyllite, and other deletereous materials.DOI: http://dx.doi.org/10.3126/bdg.v14i0.5436Bulletin of the Department of Geology Vol.14 2011, pp. 29-34  

scholarly journals PENGARUH PENGGUNAAN AIR KOLAM TERHADAP KUAT TEKAN BETON (Studi Kasus Kecamatan. Kateman, Keritang dan Tembilahan Kota)

2020 ◽  
Vol 6 (3) ◽  
pp. 153-162
Author(s):  
Muhammad Juldin ◽  
Akbar Alfa
Keyword(s):  
Compressive Strength ◽  
Concrete Specimen ◽  
Well Water ◽  
Fine Aggregate ◽  
Concrete Aggregates ◽  
Coarse Aggregates ◽  
Fine Aggregates ◽  
Pass Through ◽  
Average Compressive Strength

AbstractConcrete is a composite material (mixture) consisting of cement, coarse aggregates, fine aggregates and water. The concrete formation mixture is designed in such a way as to produce fresh concrete that is easy to work with and meets the plan's compressive strength after hardening.The cement used is PCC type cement, although the composition of cement in concrete is only about 10%, but the role of cement is very important in concrete. Aggregates are mineral granules originating from nature or artificial which have a function as a mixture of fillers in concrete. The aggregate of the concrete mixture filler is divided into fine aggregates used from Javanese Inhu and coarse aggregates from Tanjung Balai Karimun. The fine aggregate is usually in the form of sand that passes through a filter with a diameter of 4.75 mm or 5 mm, while coarse aggregates do not pass through the filter. The water used is well water from Kateman District, Keritang District and Tembilahan District, Indragiri Hilir Regency, Riau Province.The compressive strength of concrete is the amount of load per unit area which causes the concrete specimen to break and there is no more carrying capacity. The average compressive strength of 28 days of cube specimens with well water in Kateman District = 491 kg / cm2, Keritang District = 469 kg / cm2 and Tembilahan District City = 475 kg / cm2.   AbstrakBeton merupakan bahan komposit (campuran) yang terdiri dari semen, agregat kasar, agregat halus dan air. Campuran bahan-bahan pembentukan beton dirancang sedemikian rupa, sehingga menghasilkan beton segar  yang mudah  dikerjakan  dan  memenuhi  kekuatan  tekan  rencana  setelah mengeras.Semen yang digunakan adalah semen tipe PCC, walaupun komposisi semen dalam beton hanya sekitar 10%, namun peran semen sangat penting dalam beton. Agregat adalah butiran mineral yang berasal dari alam atau buatan yang memiliki fungsi sebagai bahan pengisi campuran pada beton. Agregat pengisi campuran beton terbagi atas agregat halus yang digunakan berasal dari Japura Inhu dan agregat kasar berasal dari Tanjung Balai Karimun. Agregat halus biasanya berupa pasir yang lolos saringan dengan diameter 4,75 mm atau 5 mm, sedangkan agregat kasar tidak lolos saringan tersebut. Air yang digunakan yakni air sumur berasal dari Kecamatan Kateman, Kecamatan Keritang dan Kecamatan Tembilahan Kota Kabupaten Indragiri Hilir Provinsi Riau.Kuat tekan beton adalah besarnya beban per satuan luas yang menyebabkan benda uji beton pecah dan tidak ada lagi daya dukungnya. Hasil kuat tekan rata-rata umur 28 hari benda uji kubus dengan air sumur Kecamatan Kateman = 491 kg/ cm2, Kecamatan Keritang = 469 kg/cm2dan Kecamatan Tembilahan Kota = 475 kg/cm2.

Experimental Study on the Fundamental Characteristics of Different Parent Recycled Concrete Fine Aggregates

2013 ◽  
Vol 368-370 ◽  
pp. 1080-1085 ◽  
Author(s):  
Yong Jun Qin ◽  
Lei Li ◽  
Aihemaiti Yibulayin ◽  
Guang Tai Zhang ◽  
Rui Liang
Keyword(s):  
Concrete Strength ◽  
High Strength ◽  
Recycled Concrete ◽  
Recycled Aggregate ◽  
Fine Aggregate ◽  
Strength Concrete ◽  
Recycled Fine Aggregate ◽  
Fine Aggregates ◽  
Different Types ◽  
Overall Performance

Recycled aggregate performance vary with different native concrete strength and use environment. Recycled fine aggregate was obtained after the primary concrete was broken and screened. According to Recycled coarse aggregate for concrete and mortar (GB/T 25176-2010), the physical properties of the different types of recycled fine aggregate were analyzed, in addition, determine the classification. The results shows that the properties of recycled fine aggregate all meet the level and they are vary by strengths of its maternal primary concrete and using environments. The overall performance of fine aggregate of high strength primary concrete is the best, followed by the low strength concrete and the moderate strength concrete.

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