A Coupled Chemo-Mechanical and Life-Cycle Framework for Oyster-Shell-Derived Cementitious Materials in Aggressive Infrastructure Environments

Manuscript prepared for Construction and Building Materials (Elsevier). A coupled hydration-transport-damage-carbon Monte Carlo framework asks under which processing, substitution and exposure conditions oyster-shell-derived concrete delivers a joint carbon and service-life advantage over ordinary Portland cement concrete, and where that claim fails. Uncalcined shell powder replacing cement (P1) and shell calcium carbonate replacing limestone in the kiln feed (P2) are separated; three infrastructure cases (pavement, dam, marine culvert); paired shell/OPC draws, Sobol sensitivity and an explicit falsification region. A filler-efficiency extension is calibrated by rejection ABC on published scallop-shell concrete data (Abbas and Kudukkan 2025) with a held-out mix, and the claims are re-evaluated under the calibrated posterior. In-silico study; no new experiments; conclusions are conditional on the stated assumptions. Code, tests and results: https://github.com/sandlerleon/oyster-shell-concrete-mc.