Title:
Mechanical, Durability, and Time-Dependent Properties of Recycled Aggregate Concrete with Fly Ash
Author(s):
M. Surya, V. V. L. Kanta Rao, and Parameswaran Lakshmy
Publication:
Materials Journal
Volume:
112
Issue:
5
Appears on pages(s):
653-662
Keywords:
concrete resistivity; creep and shrinkage; mechanical properties; rapid chloride permeability test (RCPT); recycled aggregate concrete; recycled concrete aggregate
DOI:
10.14359/51687853
Date:
9/1/2015
Abstract:
This paper presents the results of tests on mechanical properties, durability, short-term testing for creep, and drying shrinkage of recycled aggregate concrete (RAC). A natural aggregate concrete (NAC) mixture was designed for a characteristic compressive strength of 40 MPa (5.8 ksi) and the natural coarse aggregate (NA) was replaced by coarse recycled concrete aggregate (RCA) at 50, 75, and 100%. The existing concrete mixture design method was slightly modified to design the RAC mixtures, taking into account the lower specific gravity of the RCA. Fly ash was used as mineral admixture. The test results were compared with those of NAC and the NAC containing fly ash (NAF). The RAC exhibited comparable slump and strength to, and lower elastic modulus than, that of NAC. The resistivity was higher and chloride permeability was lower for RAC when compared to NAC; however, the same were inferior to NAF. The drying shrinkage strain of RAC mixture with 100% RCA was observed to be 1.24, 1.37, and 1.41 and creep strain was 1.15, 1.10, and 0.98 times that of NAC at 30 days, 60 days, and 90 days, respectively.