ABOUT THE INTERNATIONAL CONCRETE ABSTRACTS PORTAL

  • The International Concrete Abstracts Portal is an ACI led collaboration with leading technical organizations from within the international concrete industry and offers the most comprehensive collection of published concrete abstracts.

International Concrete Abstracts Portal

Showing 1-5 of 15 Abstracts search results

Document: 

SP347

Date: 

March 15, 2021

Publication:

Symposium Papers

Volume:

347

Abstract:

Sponsors: Sponsored by ACI 370 Committee Editors: Eric Jacques and Mi G. Chorzepa This Symposium Volume reports on the latest developments in the field of high strain rate mechanics and behavior of concrete subject to impact loads. This effort supports the mission of ACI Committee 370 “Blast and Impact Load Effects” to develop and disseminate information on the design of concrete structures subjected to impact, as well as blast and other short-duration dynamic loads. Concrete structures can potentially be exposed to accidental and malicious impact loads during their lifetimes, including those caused by ballistic projectiles, vehicular collision, impact of debris set in motion after an explosion, falling objects during construction and floating objects during tsunamis and storm surges. Assessing the performance of concrete structures to implement cost-effective and structurally-efficient protective measures against these extreme impacting loads necessitates a fundamental understanding of the high strain rate behavior of the constituent materials and of the characteristics of the local response modes activated during the event. This volume presents fourteen papers which provide the reader with deep insight into the state-of-the-art experimental research and cutting-edge computational approaches for concrete materials and structures subject to impact loading. Invited contributions were received from international experts from Australia, Canada, China, Czech Republic, Germany, South Korea, Switzerland, and the United States. The technical papers cover a range of cementitious materials, including high strength and ultra-high strength materials, reactive powder concrete, fiber-reinforced concrete, and externally bonded cementitious layers and other coatings. The papers were to be presented during two technical sessions scheduled for the ACI Spring 2020 Convention in Rosemont, Illinois, but the worldwide COVID-19 pandemic disrupted those plans. The editors thank the authors for their outstanding efforts to showcase their most current research work with the concrete community, and for their assistance, cooperation, and valuable contributions throughout the entire publication process. The editors also thank the members of ACI Committee 370, the reviewers, and the ACI staff for their generous support and encouragement throughout the preparation of this volume.

DOI:

10.14359/51732675


Document: 

SP-347_08

Date: 

March 1, 2021

Author(s):

Alex Remennikov and Edward Chern Jinn Gan

Publication:

Symposium Papers

Volume:

347

Abstract:

Explosively formed projectiles (EFP) are one of the most severe explosive and impact loading threats for civil infrastructure and military vehicles. EFP warheads are commonly found in conventional anti-tank weapons. They are also regularly used by insurgent forces against armoured vehicles in conflict-affected countries. The energy of EFPs is significantly greater than that of large calibre ammunition, such that a threat is posed to the occupants of armoured vehicles both by perforation and spalling of the armour. This paper aims to present new experimental results of the hypervelocity impact of EFPs on reinforced concrete (RC) columns to demonstrate the vulnerability of infrastructure to EFP improvised explosive devices (EFP-IEDs). As a possible mitigation measure of threat against EFPs, an RC column was retrofitted with a steel-jacket. The ability of a steel-jacket to minimise RC column damage was evaluated where it was found to minimise damage to the RC column and contain concrete fragments. Threedimensional numerical simulations were performed to elucidate the different stages of EFP interaction with the RC columns. No previously published results on the EFP terminal ballistic performance of RC columns have been found in the open literature.

DOI:

10.14359/51732662


Document: 

SP-347_12

Date: 

March 1, 2021

Author(s):

Assem A. A. Hassan

Publication:

Symposium Papers

Volume:

347

Abstract:

The inclusion of rubber in concrete mixtures improved the impact resistance but negatively affected the strength and fresh properties of self-consolidating concrete (SCC). The objective of this investigation was to optimize the balance between the improved impact resistance and the reductions in the strength and fresh properties of rubberized SCC mixtures. This investigation evaluated and assessed the type/size and percentage of rubber needed to develop successful SCC mixtures with maximized impact strength and minimized reductions in strength. The studied variables were the type/size of rubber used (crumb rubber (CR) and two sizes of powder rubbers), percentage of rubber (0%, 15%, 25%, 30%, 35%, and 40%), type of concrete (SCC and vibrated concrete), and the use of fibers in the mixture. Because of the fresh properties restrictions of SCC, it was only possible to develop rubberized SCC with up to 25%, 30%, and 35% CR, powder rubber 40/80, and powder rubber 140, respectively. With the absence of fresh properties restrictions of SCC, it was possible to develop vibrated rubberized concrete with up to 40% of any type of rubber. Using higher percentages of rubber in vibrated rubberized concrete dropped the compressive strength to less than 25 MPa (3.63 ksi). The results also indicated that despite the slight improvement in the fresh properties and strength of mixtures with powder rubbers compared to mixtures with CR, mixtures with CR showed significantly higher improvements in the impact resistance.

DOI:

10.14359/51732666


Document: 

SP-347_14

Date: 

March 1, 2021

Author(s):

Seong Ryong Ahn and Thomas H.-K. Kang

Publication:

Symposium Papers

Volume:

347

Abstract:

Impact resistance of concrete panels has been researched since the 19th century. Studies therein primarily focused on conventionally reinforced concrete and steel fiber-reinforced concrete. Little research on the impact resistance of prestressed concrete exists. This paper investigated the impact resistance of prestressed concrete panels subject to hard and soft/hollow projectiles and under an assortment of prestressing levels. Damage mode, velocity change, impact force, and internal energy were measured and analyzed. A total of twelve finite element analyses, which considered high strain rate effects, were performed, as well as preliminary analyses with different mesh sizes. It is observed that level of prestressing tends to improve perforation resistance of concrete panels. Additionally, large deformation at soft projectiles occurred during impact, consuming the greater internal energy of the projectiles, unlike hard projectiles. As a result, soft projectiles caused a smaller degree of local failure on the concrete panels than hard projectiles with the same mass and velocity.

DOI:

10.14359/51732668


Document: 

SP-347_10

Date: 

March 1, 2021

Author(s):

Grace Darling, Stephan A. Durham, and Mi G. Chorzepa

Publication:

Symposium Papers

Volume:

347

Abstract:

Concrete median barriers (CMB) are installed to decrease the overall severity of traffic accidents by producing higher vehicle decelerations. In 2016, an update to the AASHTO Manual for Assessing Safety Hardware (MASH) saw a 58% increase in impact severity of test level 4 (TL-4) impact conditions when compared to the NCHRP Report 350 testing criteria. This study investigates the use of fiber-reinforced rubberized CMBs in dissipating the impact energy to improve driver safety involved in crashed vehicles. Two full-scale barrier prototypes with shear keys were constructed and tested under impact conditions in a laboratory setting. Compared to the Georgia Department of Transportation specified single-slope barrier, the fiber-reinforced rubberized concrete mixture, a design with 20% replacement of the coarse aggregate by volume with recycled rubber tire chips and a 1.0% steel fiber addition, was evaluated based on its performance in toughness, energy absorption capacity, and its recoverable deformation. It is concluded that the TC20ST1 barrier performed as well as the control barrier at the impact load of 150.0 kips (667.2 kN), with neither barrier experiencing any visible damage.

DOI:

10.14359/51732664


123

Results Per Page