Properties of previous concrete made with recycled concrted aggregates and cement additions

Abstract

Results of an investigation on mechanical and durability properties of pervious concrete made with Coarse Recycled Concrete Aggregates (RCA) as partial or complete replacement of Coarse Natural Aggregates (NA) are presented. The relative efficacy of Silica Fume (SF) and Metakaolin (MK) in compensating loss of strength and durability properties of the pervious concrete mixes due to the use of RCA was evaluated. To assess the mechanical properties of pervious concrete mixes, tests such as compressive strength, split tensile strength and flexural strength tests were conducted on all the pervious concrete mixes. The ultrasonic pulse velocity tests were also conducted on various pervious concrete mixes. In order to assess the fatigue performance, flexural fatigue tests were conducted on some selected pervious concrete mixes. Further, to assess the durability properties of various pervious concrete mixes, tests such as porosity and permeability were conducted on all the mixes whereas, acid resistance tests were conducted on some selected mixes. The compressive strength tests on all the pervious concrete mixes were conducted after 7, 28, 56 and 90 days of curing whereas split tensile strength, flexural strength and ultrasonic pulse velocity tests were conducted after 28, 56 and 90 days of curing. Flexural fatigue strength tests on pervious concrete mixes were conducted after 56 days of curing age. Cylindrical specimens of size 200 mm × 100 mm, cubical specimens of size 100 mm × 100 mm × 100 mm and beam specimens of size 100 mm × 100 mm × 500 mm were tested for the properties mentioned wherein the replacement levels of NA with RCA were kept at 0%, 25% 50%, 75% and 100%. Incorporation of SF and MK (upto 10%) in the binder mix was done in such a way to convert the binary blended mixes to ternary and quaternary blended mixes. The control pervious concrete mix consisted of 100% NA with 70% Ordinary Portland Cement (PC) and 30% Fly Ash (FA) thus resulting in binary blended pervious concrete mix. The maximum degrad