Dissertação
Microestrutura e durabilidade a cloretos de protótipos de concreto com cinza de casca de arroz com e sem moagem prévia
Fecha
2013-02-27Registro en:
SOKOLOVICZ, Bóris Casanova. MICROSTRUCTURE AND DURABILITY OF A CHLORIDE
PROTOTYPES WITH CONCRETE GRAY RICE HUSK WITH AND
WITHOUT PRIOR GRIND. 2013. 165 f. Dissertação (Mestrado em Engenharia Civil) - Universidade Federal de Santa Maria, Santa Maria, 2013.
Autor
Sokolovicz, Bóris Casanova
Institución
Resumen
Cement is the main component of concrete, which is the second most common
material used by man. The cement manufacturing process is largely responsible for
the emission of carbon dioxide in the atmosphere. The construction industry has
been studying the possibility of using agroindustrial byproducts for cement mortars,
which aims to reduce the environmental impact of cement production and promote
improvements in the performance of concrete. In this context, the rice husk ash is
one of the most studied mineral additions, as well as being an industrial waste widely
available, generally provides a longer service life of reinforced concrete structures.
This paper investigates the microstructure and durability of rice husk ash and
residual natural, unprocessed prior production of structural concrete. We studied
prototypes of concrete with dimensions of 20 x 20 x 75 cm with partial replacement of
cement by rice husk ash and milled in natural levels of 0%, 15% and 25% in the
relations / ag 0.45; 0 55 and 0.65. These prototypes were exposed to natural
environmental conditions, up to 540 days. We conducted tests of compressive
strength, water chemically combined (AC), mercury intrusion porosimetry (MIP),
accelerated penetration of chlorides (EAPC) by the method of ASTM C 1202 and
total chlorides retained. The results showed that the compressive strength at 540
days showed the highest values for mixtures with crushed CCA, while mixtures
containing natural CCA showed the lowest resistance being lower than the reference
blend. In assay mixtures containing CCA AC ground showed the best performance.
For testing PIM, mixtures that showed the highest amounts of mesopores and pores
of gel mixtures were milled with CCA, where there was the refinement of the pores of
the 91 days to 540 days, thereby reducing the porosity of these mixtures. For the test
of EAPC, mixtures ground with CCA showed the lowest cargo bystanders, especially
the mixture with 25% substitution. The blends with natural CCA showed loads
passers below the reference mixture, showing a good performance. For the assay of
the total content of chloride retained, mixtures with CCA ground showed the lowest
levels, confirming that the best performance of CCA promotes grinding on concrete.
The blends with natural CCA showed values very close to the reference mixture. The
results show the technical feasibility of CCA natural levels in 15% of partial
replacement of cement.