RT info:eu-repo/semantics/article
T1 Mechanical performance and autogenous and drying shrinkage of MgO-based recycled aggregate high-performance concrete
A1 Revilla Cuesta, Víctor
A1 Evangelista, Luís
A1 Brito, Jorge de
A1 Skaf Revenga, Marta
A1 Ortega López, Vanesa
K1 High-performance concrete
K1 Recycled aggregates
K1 Recycled aggregate’s maturity
K1 Magnesium oxide
K1 Autogenous shrinkage
K1 Drying shrinkage
K1 Ingeniería civil
K1 Civil engineering
K1 Materiales de construcción
K1 Building materials
AB The high strength and durability of high-performance concrete (HPC) may be significantly reduced by shrinkage cracking. The use of reactive magnesium oxide (MgO) can reduce shrinkage of cement-based materials due to its expansive properties. This study intends to analyse the validity of MgO as shrinkage-reducing agent in recycled aggregate HPC. To do so, ten HPC mixes with 0%, 25%, and 100% of both early-age (7-days air curing) and matured (6-month air curing) RA were produced. In half of the mixes, 10% ordinary Portland cement was replaced with MgO. The use of MgO slightly worsened the mechanical behaviour of HPC, especially when combined with large amounts of RA. On the other hand, the expansion of MgO fully offset the autogenous shrinkage of HPC and reduced total shrinkage by around 20–40%. Water storage of RA, and its deferred release over time, produced a more efficient hydration of MgO, which in turn led to a further reduction of autogenous shrinkage. However, the increase of drying shrinkage caused by RA was greater than this decrease of autogenous shrinkage due to MgO, so the higher the RA content of HPC the lower the total shrinkage reduction when adding MgO. Thus, the decrease of total shrinkage caused by MgO was compensated by the shrinkage increase because of RA when adding amounts above 35% early-age RA and 42% matured RA. Therefore, despite the suitability of MgO as shrinkage-reducing agent in recycled aggregate HPC, its effectiveness was reduced with increasing amounts of RA.
PB Elsevier
SN 0950-0618
YR 2022
FD 2022-01
LK http://hdl.handle.net/10259/6372
UL http://hdl.handle.net/10259/6372
LA eng
NO Spanish Ministry of Universities, MICINN, AEI and ERDF [grant numbers FPU17/03374; EST19/00263; PID2020-113837RB-I00; 10.13039/501100011033]. The authors also acknowledge the support of the Foundation for Science and Technology, CERIS Research Centre and Instituto Superior Técnico, the Junta de Castilla y León [grant number UIC231], and the University of Burgos [grant number Y135.GI].
DS Repositorio Institucional de la Universidad de Burgos
RD 24-nov-2024