Granular effect of fly ash repairs damage of recycled coarse aggregate

2008 ◽  
Vol 13 (2) ◽  
pp. 177-180 ◽  
Author(s):  
Jiu-su Li ◽  
Han-ning Xiao ◽  
Jian-qing Gong
Keyword(s):  
Fly Ash ◽  
Coarse Aggregate ◽  
Recycled Coarse Aggregate

scholarly journals Strength and abrasion performance of recycled aggregate based geopolymer concrete

2021 ◽  
Author(s):  
Asfaw Mekonnen LAKEW ◽  
Mukhallad M. AL-MASHHADANI ◽  
Orhan CANPOLAT
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Fly Ash ◽  
Coarse Aggregate ◽  
Steel Fiber ◽  
Splitting Tensile Strength ◽  
Partial Replacement ◽  
Geopolymer Concrete ◽  
Recycled Coarse Aggregate ◽  
One Year

This experimental work evaluated geopolymer concrete containing fly ash and slag by partial replacement of natural coarse aggregate (NCA) with recycled coarse aggregate (RCA) to manufacture environmental-friendly concrete. The proportion of recycled aggregates considered consists of 10%, 20%, 30%, and 40% of the total coarse aggregate amount. Also, a steel fiber ratio of 0.3% was utilized. The mechanical properties and abrasion resistance of fly ash/slag-based geopolymer concrete were then assessed. Majorly, the mechanical strength of the concrete samples decreased by the increase of RCA content. The geopolymer concrete with 40% RCA gave 28.3% lesser compressive strength and 24% lower splitting tensile strength than NCA concrete at one year. Also, the flexural strength of concrete specimens was reduced by 35% (from 5.34MPa to 3.5MPa) with the incorporation of 40% RCA. The incorporation of 30% RCA caused 23% and 22.6% reduction in compressive strength at 56 days and one year, respectively. The flexural and splitting tensile strength of the specimens was not significantly reduced (less than 10%) with the inclusion of a recycled coarse aggregate ratio of up to 30%. Furthermore, the abrasion wear thickness of every concrete sample was less than 1mm. RCA inclusion of 20% produced either insignificant reduction or better strength results compared to reference mixtures. As a result, it was considered that the combination of 0.3% steel fiber and 20% recycled coarse aggregate in fly ash/slag-based geopolymer concrete leads to an eco-friendly concrete mix with acceptable short and long-term engineering properties that would lead to sustainability in concrete production and utilization sector.

Microscopic Mechanism Study on Carbonation Resistance of Recycled Aggregate Concrete

2011 ◽  
Vol 194-196 ◽  
pp. 1001-1006 ◽  
Author(s):  
Hai Feng Yang ◽  
Zhi Heng Deng ◽  
Xue Liang Li
Keyword(s):  
Fly Ash ◽  
Coarse Aggregate ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Replacement Rate ◽  
Aggregate Concrete ◽  
Recycled Coarse Aggregate ◽  
Concrete Carbonation ◽  
Carbonation Resistance

24 100mm × 100mm × 300mm recycled concrete prisms and 96 150mm × 150mm × 150mm cubes are completed in this paper.The relationships of the carbonation depth in each carbonation age with replacement rate of recycled coarse aggregate and fly ash is studied; The SEM is used to observe the interface structure of recycled coarse aggregate concrete and compared with ordinary concrete, and finally,a recycled concrete carbonation model is proposed. The results showed that: the substitution of recycled coarse aggregate and fly ash cut down the recycled concrete carbonation resistance significantly, which are related with the replacement rate; the content of Ca(OH)2 in the recycled aggregate concrete decreased ,also there are obvious interface transition zone between the recycled coarse aggregate and the new cement;obvious cracks and large voids are exist before the recycled aggregate concrete is loaded, which lead directly to lower carbonation resistance of the recycled concrete.

scholarly journals Development of Self Curing Geopolymer Concrete Incorporating Expanded Polystyrene, Recycled Coarse Aggregate and Rubber Crumbs

2020 ◽  
Vol 9 (2) ◽  
pp. 292-296
Keyword(s):  
Fly Ash ◽  
Industrial Waste ◽  
Coarse Aggregate ◽  
Expanded Polystyrene ◽  
Waste Materials ◽  
Environmental Concerns ◽  
Geopolymer Concrete ◽  
Sustainable Building ◽  
Pond Ash ◽  
Recycled Coarse Aggregate

Sustainable building production includes the effective usage of natural materials by the processing of waste materials. The present work aims to use different waste materials, such as fly ash, industrial waste pond ash, rubber crumbs from rubber tires, recycled coarse aggregate from building waste. In doing so, the goal of reducing building costs will be achieved and can help to solve the issues connected with its disposal, particularly the environmental concerns of the area. Throughout this project, Rubber Crumbs (RC) and Recycled Coarse Aggregate (RCA) were partly substituted instead of coarse aggregate with a percentage of 10, 15, 20, and 5, 10, 15, which were found to improve the flexural strength of concrete. Such products may also be used for renewable building purposes.

scholarly journals Mechanical Strength Properties of Geo Polymer Concrete incorporating Quarry Rock Dust and Recycled Coarse Aggregate

2019 ◽  
Vol 8 (4) ◽  
pp. 8414-8419
Keyword(s):  
Fly Ash ◽  
Mechanical Strength ◽  
Coarse Aggregate ◽  
Strength Properties ◽  
Source Material ◽  
Waste Materials ◽  
Polymer Concrete ◽  
Fine Aggregate ◽  
Recycled Coarse Aggregate ◽  
Rock Dust

Utilization of waste materials in concrete are increasing day by day. Ingredient replacements in concrete using waste materials are one of such threads which bind nature and concrete in a greener way to provide a better environment for the future. Reduction in environmental pollution, effective usage of waste management, the economic factor and quality of concrete are the predominant aspects by which the replacement materials are chosen.[1] Geopolymer Concrete has emerged as one of the possible alternatives to OPC, since 100% of fly ash is used instead of Portland Cement.. In this present study, the prime material which is used as the source material is fly-ash (ASTMC618) which completely replaces cement..Also fine aggregate has become very expensive and scarcity, quarry rock dust have been replaced for fine aggregate. Almost all the demolition and construction waste have been dumped without any usage which ultimately results in pollution.[2] This prime factor is considered to reutilize recycled coarse aggregate instead of coarse aggregate . A greener aided with natural friendly claim can be made only with the usage of the waste materials. To find the better combination mix, the GPC is categorized into four types as GPC-1, GPC-2, GPC-3 and GPC-4. In all the above combination of mixes fly ash is used as prime source material whereas QRD and RCA are replaced with different combinations. Thus this paper, particularly focuses on the effect of replacement of waste materials in combination of different mixes such as FA+CA, QRD+CA, FA+RCA, and QRD+RCA in GPC. The casted specimens are cured at ambient temperature and after three days of rest period, the casted specimens are tested to determine its mechanical strength properties using standard methodology.

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