Ms. Micheli S. GONÇALVES Ms. Alessandra P. CAVALHEIRO Dra. Marlova P. KULAKOWSKI Dr. Claudio S. KAZMIERCZAK Evaluation of concrete made with coarse recycled aggregate from precast concrete WASCON 2012 Gothenburg, SE GRADUATE PROGRAM CIVIL ENGINEERING Universidade do Vale do Rio dos Sinos – UNISINOS A Jesuit University – South Brazil GMAT – Research Group in Construction Materials and Recycling
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Ms. Micheli S. GONÇALVES
Ms. Alessandra P. CAVALHEIRO
Dra. Marlova P. KULAKOWSKI
Dr. Claudio S. KAZMIERCZAK
Evaluation of concrete made with
coarse recycled aggregate from
precast concrete
WASCON 2012 Gothenburg, SE
G R A D U A T E P R O G R A M
CIVIL ENGINEERING
Universidade do Vale do Rio dos Sinos – UNISINOS A Jesuit University – South Brazil
GMAT – Research Group in Construction Materials and Recycling
G R A DU A T E P R O G R AM
CIVIL ENGINEERING
Recycled concrete aggregate
(RCA) from concrete waste
Some of the problems
to use RCA is
its higher water
absorption
and its lower specific
mass
Concrete waste has a high potential for use
as recycled aggregate in structural concrete.
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0 10 20 30 40 50 60 70 80
Wa
ter
ab
so
rpti
on
(%
)
Time (min)
RCA 50 MPa
RCA 37 MPa
RCA 18 MPa
Natural Aggregate
G R A DU A T E P R O G R AM
CIVIL ENGINEERING
Recycled concrete aggregate (RCA)
from concrete waste
The ways to compensate its higher absorption can be
Pre-wetting;
Adding water to concrete mixing water;
Adding water for slump adjustment;
Aggregate saturation.
Others relevant aspects in the use of RCA
The influence of the compressive strength of the concrete which the
RCA is originated;
The quantity employed.
Previous study indicates
Maximum 50% ratio of RCA content
Maximum rate of 50% to compensate RCA water absorption.
WASCON 2012 Gothenburg, SE
G R A DU A T E P R O G R AM
CIVIL ENGINEERING
Aim
Case study
The research project was developed in a
partnership with a precast concrete industry
Porto Alegre – South Brazil;
It was carried out in laboratory;
The results helped to define some
parameters for the use of RCA in
production of precast concrete panel.
WASCON 2012 Gothenburg, SE
The purpose of this study was to investigate the influence
of recycled concrete aggregate from precast concrete
waste on mechanical properties of new concretes.
G R A DU A T E P R O G R AM
CIVIL ENGINEERING
Materials
Binding materials High early strength Portland Cement
15% of Fly Ash as mineral admixture
Superplasticizer Polycarboxylate-type
Fine natural aggregate Quartz river sand
Coarse natural aggregate Crushed basalt
WASCON 2012 Gothenburg, SE
It was employed the same materials used by the partner
industry in the production of precast concrete panels.
from production of slabs;
it is subject to conventional curing;
has 40 MPa;
RCA-C
The waste diagnosis showed that the higher quantity of
continuously generated wastes is originated from two dry-cast