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May 14, 2015 This paper discusses the suitability of producing concrete with 100 % recycled aggregate to meet durability and strength requirements for different applications. Aggregate strength, gradation, absorption, specific gravity, shape and texture are some of the physical and mechanical characteristics that contribute to the strength and durability of concrete.
Crushing value test The crushing value test was carried out by compression testing machine (CTM). The total load of 40 tones was applied at the rate of 4 ton per minute. The percentage crushing value was determined by divided the passing weight from total weight of aggregate. Slump Test The Unsupported fresh concrete, flows to the
Crushing Value (ACV) and Aggregate Impact Value (AIV) are chosen as indicator of aggregate strength. The properties are tested in laboratory following standard procedures and the test results are compared with standard requirement so as to suggest potential use of recycled aggregate after each generation of recycling.
absorption and specific gravity, (iii) aggregate crushing value and aggregate impact value. 2.1 The Properties The recycled aggregates are generated from demolished construction by crushing using steel hammer. It is then put into jaw crusher where it is broken down into required sizes. The crushed materials are sieved using a vibrator sieve in ...
Dec 28, 2020 Compared with recycled concrete aggregates, there are more mortars attached to recycled brick aggregates. Thus, the water absorption rate and crushing value of recycled brick aggregates are larger than those of recycled concrete aggregates 41, 42. The indexes of fine aggregate are shown in Table 3.
Nov 09, 2014 The aim of this paper is to evaluate the influence of the crushing process used to obtain recycled concrete aggregates on the performance of concrete made with those aggregates. Two crushing methods were considered primary crushing, using a jaw crusher, and primary plus secondary crushing (PSC), using a jaw crusher followed by a hammer mill.
Table 4- Result of Aggregate Impact Value Test on Coarse Aggregate (20mm) and RAP Table 5- Result of Aggregate Crushing Value Test on Coarse Aggregate (20mm) and RAP Weight of sand 0.5 kg Weight of pycnometer or gas jar containing sand and filled with water 1.932 kg Weigh of pycnometer or gas jar filled with water only 1.613 kg
Sep 27, 2020 Recycled aggregates are only classified as recycled concrete aggregates (RCA) when the primary material is concrete. By crushing and compressing existing waste concrete and combining it with aggregate, producers can create concrete aggregate to a specific size and quality, which makes it very cost effective to purchase.
Mar 31, 2020 Recycled concrete as aggregates are relatively weaker in strength as compared to the natural aggregates. Crushing and abrasion value of RCA is also lower then natural aggregates. The NA (natural aggregate) has an ACV (aggregate crushing value) that was about 27% higher than RCA-1, 43% higher than RCA-2 and 57% higher than RCA-3.
Aggregate crushing value test on coarse aggregates gives a relative measure of the resistance of an aggregate crushing under gradually applied compressive load. Coarse aggregate crushing value is the percentage by weight of the crushed material obtained when test aggregates are subjected to a specified load under standardized conditions.
Apr 26, 2018 Aggregate crushing test. The strength of the aggregate can be assessed by conducting this test. The aggregate crushing value gives a relative measure of the resistance of an aggregate to crushing under a gradually applied compressive load. Size of recycled aggregates taken for conducting test was between 12.5mm and 10mm.
This paper presents an experimental research on mechanical properties of recycled aggregate concrete (RAC) at low and high water/binder (W/B) ratios. Concrete at two W/B ratios (0.255 and 0.586) was broken into recycled concrete aggregates (RCA). A type of thermal treatment was employed to remove mortar attached to RCA. The RAC at a certain (low or high) W/B ratio
Jan 20 2017 0183 32 Crushing strength impact value abrasion resistance and elastic modulus of aggregate are interrelated properties that are greatly influenced by porosity Aggregates from natural sources that are commonly used for making normal-weight concrete are generally dense and strong therefore they are seldom a limiting factor to ...
Table 1 Physical properties of NA and RCA Type Used Aggregate Relative Absorption 10% Fact Flakiness in step size (mm) density (%) value (kN) index NA 1-4 9.5 - 19 2.74 0.65 370 25 RCA-1 1 9.5 - 19 2.48 5.24 88 18 RCA-2 2 9.5 - 19 2.52 4.40 125 19 RCA-3 3-4 9.5 - 19 2.54 3.49 135 21 2.2 Concrete compressive strength The 28-days compressive ...
Mar 15, 2017 The overall results indicate that it is feasible to use recycled aggregates for making pervious concrete with acceptable properties including permeability coefficient and total void ratio, and the properties of RAPC are greatly related to crushing index of recycled aggregates. When crushing index is greater than 24%, pervious concrete using recycled
Dec 10, 2020 Crushing treatment on recycled aggregates to improve their mechanical behaviour for use in unbound road layers. ... In Fig. 8, where the CBR value and the compressive strength in the swelling test have been correlated (from Table 5), the higher the value of CBR is, the higher the value of compressive strength is, too. The latter has been ...
May 14, 2015 Full size table. Compressive strength Cubes (150 mm 150 mm 150 mm) were tested for compressive strength according to (ASTM 2011a) at 3, 7, 14, 21, and 28 days, strength development with time is shown in Fig. 8. Compressive strength of concrete produced with the recycled aggregate was in the range of 41 to 52 MPa.
If the gravel proportion exceeded 75%, the aggregate crushing value was reduced by 30%. Based on the numerical and experimental investigations of the crushing characteristics of
Aug 18, 2020 The strength reduction of concrete produced from recycled coarse aggregate and natural fine aggregate ranges from 5% 24%. This influenced by the strength of crushed concrete, water to cement ration of crushed and new concrete. For concrete produced from both recycled coarse and fine aggregate is between 15% 40%.
May 05, 2021 According to the analysis results of the nonlinear fitting curves between the property indexes of mixed recycled coarse aggregate (water absorption and crushing value) and the performance parameters of mixed recycled coarse aggregate concretes (cubic compressive strength, prism compressive strength, splitting tensile strength, static modulus
The 100% of RA used in concrete mix to replace the natural coarse aggregate in concrete with 100 x 100 x 100 cube mm were cast with target compressive strength is 25 MPa. The 28-day compressive strength was crushed at 3, 14, 28 days are reported.
Strength of aggregate is evaluated in laboratory by Aggregate Crushing Value (ACV) test and Aggregate Impact Value (AIV) test after each generation of recycling. The ACV and AIV values of
It was found that compressive strength of concrete made from the recycled aggregate is about 76% of the strength of concrete made from natural aggregate for normal strength concrete (M20). Flexural strength of the recycled aggregate concrete is almost 85% and 80% of natural aggregate concrete.
Feb 28, 2019 Different portions of the recycled aggregate hold varying measures of specific gravity, characterizing the cured casts strength, compression-resistance, and modulus elasticity. However, using a recycled aggregate of more than 65% can impact the mixs durability significantly, reducing its physical properties tenfold.
Dec 12, 2013 The most important parameters associated with recycled concrete aggregate (RCA) production that may affect quality and yield include such properties of the parent concrete as the composition, strength and aggregate grading, type of crushers used, number of crushing stages, the size of the RCA particles, and the size reduction sequence.
Recycling is the act of processing the used material for use in creating new product. The usage of natural aggregate is getting more intense with the development in infrastructure area. In order to reduce the usage of natural aggregate, recycled aggregate can be
Dec 19, 2019 The aggregate crushing value test indicates the strength of aggregate which is the most essential property of coarse aggregate. The aggregate crushing value provides a relative measure of resistance to crushing under a gradually applied compressive load. For achieving a high quality of pavement, aggregate of higher crushing strength i.e. low ...
articleosti_7310891, title Use of recycled concrete as aggregate. Final report, author Buck, A D, abstractNote Supplies of natural mineral aggregates are diminishing as their usage increases. Disposal problems exist because of steadily increasing accumulation of solid wastes. In light of these two situations an investigation was made to evaluate the use of
After that, these recycled concretes were used as second recycled aggregates to produce RAC with the same objectively compressive strength of 30MPa. The physical properties of coarse aggregates including apparent density, water absorption, attached mortar content and crushing value were tested and their mineral characteristics were analyzed.
Jan 01, 2014 Water Absorption and Crushing Value of Coarse Aggregate. The results of water absorption tests on various types of aggregates are given in Figure 2. ... Effect of microstructure of ITZ on compressive strength of concrete prepared with recycled aggregates, Construction and Building Materials, vol. 18, no. 6, pp. 461-468, 2004.
C.S. Poon et al. / Construction and Building Materials 18 (2004) 461468 463 Table 3 Physical properties of natural and recycled coarse aggregates Type of coarse Ten percent Apparent Water absorption As-received moisture aggregate fines crushing density (kgym3) (%) content (%) value (kN) 10 mm 20 mm 10 mm 20 mm Crushed granite 159.7 2.620 1 ...
behavior of recycled aggregate in concrete structures. experimenting fresh and hardened concrete, mixtures containing recycled aggregates. The percent of fine recycled aggregate in the all recycled aggregate was about 5.0% so it was excluded from the study. 0 %,30 % and 60 % of coarse recycled aggregate was used in the experimental tests .
Sep 21, 2021 When the cement dosage was the same, the unconfined compressive strength decreased as the amount of recycled aggregate increased. This was because the crushing value of the recycled construction waste material was higher than that of the new aggregate, and the strength was lower.
Jun 30, 2011 Recycled concrete qualifies for recycled material credits, and because it usually is found locally, it qualifies for local credits. Concrete with recycled concrete aggregate has a smaller carbon footprint. Crushing old concrete to produce aggregate takes less energy than mining virgin aggregate.
Jan 01, 2017 The crushing value of RA varies greatly, and its crush resistance ability is significantly lower than the NA, as is shown in Figure 4. ... 10 X. Yuezhou, The Numerical Simulation and Influence of Aggregate Gradation on the Compressive Strength of Recycled Aggregate Concrete, Xiamen University, 2007. 11 Z. Zhang, K. Wang, H. Liu, and Z. Deng ...