prediction of compressive strength of recycled aggregate,yond 28-days,on the compressive strength of recycled aggregate concrete. for this purpose, a predictive model has been construct - ed usinga dataset [19] with 31 test results containing recycled aggregates at various water-cement and replacement ratios, ex-posed to.effect of recycled aggregate on compressive strength of,recycled aggregate is suitable to apply in the construction area. the compressive strength of recycled aggregate concrete was relatively lower and variation was depended on the strength of parent concrete from the obtained aggregate. [4] iii. priliminary investigation the cement was an ordinary portland cement shall confirm is 12269..
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recycled aggregate posses relatively lower bulk density, crushing and impact values and higher water absorption as compared to natural aggregate. the compressive strength of recycled aggregate concrete is relatively lower up to 15% than natural aggregate concrete.
figure 2.2 the effect of recycled concrete aggregate on concrete compressive strength (after yang et al. 2008).. 24 figure 3.1 sieve analyses of (a) natural fine aggregate, (b) natural coarse aggregate, and (c)
strength and durability characteristics of recycled concrete aggregates dept. of civil engineering, viswajyothi college of engineering and technology, vazhakulam 14 7.3 treatment process the various steps involved in the treatment process are as follows : 7.3.1 washing the aggregates collected by sieve analysis were washed by pressure washing about 15 to 20 minutes and was kept for
the ann model, run in a matlab platform, was used to predict the compressive strength of the recycled aggregate concrete. the results show that ann has good potential to be used as a tool for predicting the compressive strength of recycled aggregate concrete prepared with varying types and sources of recycled aggregates.
when recycled aggregates are used in a concrete mix the concrete is termed as recycled aggregate concrete (rac). several researches have studied the influence of ra on concrete properties such as compressive strength, tensile strength, etc. ( ajdukiewiez and kliszczewicz, 2002 , hansen and narud, 1983 , tsung et al., 2006 , ryu, 2002 ).
from the experimental work experimental study of compressive strength of recycled aggregate concrete, the following conclusion can be made: recycling and reuse of building wastes have been found to be an appropriate solution to the problems of dumping hundred of thousands tons of debris accompanied with shortage of natural aggregates.
this study examined that compressive and flexural strengths of recycled aggregate concrete at 7 and 28 days and compared the strength with control mix with natural aggregates. the strengths showed very minimum fluctuations between the mixes. the compressive strength of all mixes exceeded at the age of 28 days. compressive strength of control mix
recycled aggregate (ra) -used as coarse aggregatethe recycled coarse aggregates were produced by crushing the waste concrete cubes at outer uthm material laboratory that had compressive strength between 20 to 25 mpa.
compressive strength of fine recycled aggregate concrete. wainright et al [9] observed that concrete mixes with fra could result in compressive strength increases of up to 5 mpa in some cases. leite [14] noted that the incorporation of fra in contrast to cra increased the concrete’s compressive strength. khatib [7] observed a general loss of
therefore, under the experimental conditions of this investigation, it may be concluded that the recycled coarse aggregate content has only a marginal influence on the coefficient of variation of the compressive strength of recycled aggregate concrete.r = 0 r = 0 r = 30% r = 30% r = 50% r = 50% r = 100% r = 100% (a) (b) f x ( ) 4 summary and conclusionsin this paper, a statistical analysis
this paper investigates the effect of recycled con-crete aggregate (rca) on the rate of concrete compressive strength and stiffness gain with time and on the bond strength between seven-wire steel prestressing strand and concrete. the use of rca did not have a significant effect on the rate of concrete compressive strength or stiffness
this chapter intensively studied the strength indexes of recycled aggregate concrete (rac), which includes the rac compressive strength, tensile strength, flexural strength, the relationship of the conversion coefficients of rac mechanical index, and the effects of elevated temperatures on the rac strengths. the research results in this chapter are
compressive strength. compressive strength of rca concrete can be influenced by the properties and amount of recycled aggregate. several factors can influence the compressive strength in rca concrete, including the water/cement (w/c) ratio, the percentage of coarse aggregate replaced with rca, and the amount of adhered mortar on the rca.
compressive strength of concrete produced with the recycled aggregate was in the range of 41 to 52 mpa. mix 4 had the lowest compressive strength. this was expected due to the nature of grade 4, which has poor particle distribution and contains different impurities.
use of combinations of coarse and fine rap aggregate in normal concrete mixes and compared the results of compressive strength to conventional mixes with 0.4 and 0.5 water cement ratios. compressive strength values were found to decrease with the
disadvantages of recycled aggregate. downgrading of quality of concrete. increase in water absorption capacity ranging from 3% to 9%. decrease in compressive strength of concrete (10-30%) reduces workability of concrete. lack of specifications and guidelines.
the results shows that when the water cement ratio is 0.86 and the mass ratio of recycled aggregate to cement is 5.5 and the dosage of activator is 0.25% (mass fraction with recycled aggregate), the compressive strength of sample is 22.5mpa and can be satisfied with the requirement of mu20 solid concrete brick. 108.
many previous studies have presented that the compressive strength of recycled concrete mixed with a certain proportion of ﬁne recycled concrete aggregates (frcas) is greatly reduced due to the large water absorption rate of frcas [27–29]. additionally, the adverse effect of frcas on concrete is greater than that of coarse recycled concrete
pose a prediction methodology for recycled concrete compressive strength. there are many variables that influence recycled concrete compressive strength (grading curves, maximum size fraction, natural aggregate source, cement class, possible admixtures, etc.) which have not been taken into account. in
and density with time. reduction in the 28 -day compressive strength of concrete due to complete replacement of natural aggregates with recycled concrete aggregate ran ges from 11% to 33%. rca can replace na in the production of both non -structural and structural concrete. patil.et.al. (2013), this study aimed to evaluate physical properties
strength reduction of concrete produced from recycled coarse aggregate and natural fine aggregate ranges from 5 to 24%. this influenced by strength of crushed concrete, water to cement ratio of crushed and new concrete. for concrete produced from both recycled coarse and fine aggregate is
freeze-thaw resistance of recycled aggregate concrete with partial or total replacement of recycled aggregate compared with that of natural aggregate concrete was investigated in this paper. method: ninety specimens were fabricated to study the influence of different recycled aggregate replacement ratios on the surface scaling, mass loss, and residual compressive strength after 100 freeze-thaw
the objectives of this research are to study the concrete homogeneity at a certain sample height and to find the strength prediction of recycled aggregate concrete (rac). in the previous laboratory study, the obtained concrete compressive strength with 20% rac substitution (from the concrete ruins with fc’ = 30 mpa) was 27-30 mpa.
the results are tabulated under table 5. percentage of recycled aggregate concrete compressive strength for 7days (mpa) compressive strength for 14days (mpa) compressive strength for 21days (mpa) 100% 21.24 23.62 24.88 75% 23.70 24.98 25.99 table 5: variation of compressive strength. 12. compression test 13.