18 research outputs found
Mechanical properties of hybrid fiber reinforced concrete and a nondestructive evaluation
The problem of the equivalent time to start the internal frost resistance test on self-compacting concrete with supplementary cementitious materials
Assessment of selected parameters of concrete composite containing recyclate obtained from fire-resistant cullet
Predicting the postcracking strength of ultraâhigh performance fiber reinforced concrete by means of threeâpoint bending tests according to EN 14651
An innovative approach for temperature control of massive concrete structures at early ages based on post-cooling: Proof of concept
This study proposes a new methodology for the embedment of flexible PVC hoses (with the shape/geometry of the intended cooling pipes) that allows their removal a few hours after casting (i.e. after setting), while allowing that water is pumped through the circular cavity afterward (through a flexible/impermeable sleeve placed to shield the exposed concrete cavity). The PVC hoses are initially filled with oil under pressure, which are deflated a few hours after casting (particularly after setting is identified), and removed without relevant constraints due to their reduction in diameter inherent to deflation. All components and materials embedded into concrete (hose, sleeve) are fully recoverable after the end of the temperature control period, avoiding the loss of materials, with important financial and sustainability gains. This paper intends to show the proof-of-concept carried out in laboratory context conditions, highlighting the features that led to the selection and phasing procedure of the solution proposed.The authors gratefully acknowledge the Foundation for Science and Technology (FCT) for the financial support to: the Research Unit RISCO (FCT/UID/ECI/04450/2013), the Research Unit ISISE (POCI-01-0145-
FEDER-007633); the post-doc scholarship grant SFRH/BPD/116022/2016; the Research Project IntegraCrete PTDC/ECM-EST/1056/2014 (POCI-01-0145-FEDER-016841). The author Miguel Azenha also gratefully acknowledges the very rich discussion held with the colleague Paulo RamĂsio (University of Minho) on a unrelated matter, that ended up giving birth to the idea forwarded here. Collaboration with Raul
Fangueiro and Carlos Mota in the selection of the pipe to use in this work is also gratefully acknowledged