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Controlo de compactação de aterros em argila expandida
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Os agregados leves de argila expandida, utilizados em aterros estruturais pelo seu reduzido peso
volúmico, carecem de uma metodologia de controlo de compactação consolidada, pois os métodos
clássicos (Proctor, garrafa de areia, gamadensímetro) não são aplicáveis a este material poroso e
de comportamento frágil. Esta dissertação desenvolve e valida uma metodologia de controlo de
qualidade da compactação de aterros com argila expandida, recorrendo ao penetrómetro dinâmico
PANDA. O programa experimental incluiu ensaios em modelo reduzido, avaliando a influência da
espessura de camada e do número de passagens de compactação, e ensaios em caixas-modelo de
1 m³, que validaram o critério de redução volumétrica de 10% do EXCA (2007) e caracterizaram a
heterogeneidade da compactação. Estes ensaios foram complementados por uma caracterização
laboratorial das amostras recolhidas antes e após cada ensaio (massa volúmica, resistência
mecânica e granulometria), validando, de forma independente, parte destas conclusões. Com base
nos resultados, desenvolveu-se uma correlação original entre qd e o módulo de deformabilidade E,
a Fórmula de Correlação qd-E para Argila Expandida (2026), E = 17,77 · qd^0,681 (R² = 0,965),
sustentando um intervalo de aceitação de qd ∈ [1,25; 2,00] MPa para o controlo de compactação
de aterros com Argila Expandida em obra.
Lightweight expanded clay aggregates, used in structural embankments for their low bulk density, lack a consolidated compaction quality-control methodology, since classical methods (Proctor, sand-cone, nuclear density gauge) are not applicable to this porous, brittle-behaviour material. This dissertation develops and validates a compaction quality-control methodology for embankments built with Expanded Clay Aggregate, using the lightweight dynamic penetrometer PANDA. The experimental programme included small-scale model tests, evaluating the influence of layer thickness and number of compaction passes, and 1 m³ model-box tests, which validated the EXCA (2007) 10% volumetric-reduction criterion and characterised compaction heterogeneity. These tests were complemented by a laboratory characterisation of samples collected before and after each test (bulk density, mechanical resistance and particle size distribution), independently validating part of these conclusions. Based on the results, an original correlation between qd and the deformability modulus E was developed, the qd-E Correlation Formula for Expanded Clay Aggregate (2026), E = 17.77 · qd^0.681 (R² = 0.965), supporting a qd acceptance interval of [1.25; 2.00] MPa for compaction quality control of embankments with Expanded Clay Aggregate on site.
Lightweight expanded clay aggregates, used in structural embankments for their low bulk density, lack a consolidated compaction quality-control methodology, since classical methods (Proctor, sand-cone, nuclear density gauge) are not applicable to this porous, brittle-behaviour material. This dissertation develops and validates a compaction quality-control methodology for embankments built with Expanded Clay Aggregate, using the lightweight dynamic penetrometer PANDA. The experimental programme included small-scale model tests, evaluating the influence of layer thickness and number of compaction passes, and 1 m³ model-box tests, which validated the EXCA (2007) 10% volumetric-reduction criterion and characterised compaction heterogeneity. These tests were complemented by a laboratory characterisation of samples collected before and after each test (bulk density, mechanical resistance and particle size distribution), independently validating part of these conclusions. Based on the results, an original correlation between qd and the deformability modulus E was developed, the qd-E Correlation Formula for Expanded Clay Aggregate (2026), E = 17.77 · qd^0.681 (R² = 0.965), supporting a qd acceptance interval of [1.25; 2.00] MPa for compaction quality control of embankments with Expanded Clay Aggregate on site.
Descrição
Palavras-chave
Expanded clay aggregate Dynamic penetrometer PANDA Compaction control Dynamic cone resistance Deformability modulus Embankments Agregados de argila expandida Penetrómetro dinâmico PANDA Controlo de compactação Resistência dinâmica de ponta Módulo de deformabilidade Aterros