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  • 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 6 Abstracts search results

Document: 

SP326-72

Date: 

August 10, 2018

Author(s):

Lee Brankley, Ayhan Tugrul, Ladin Camci, and Dave Knight

Publication:

Symposium Papers

Volume:

326

Abstract:

The expectations of stakeholders across the construction industry value chain have increased significantly because of new legislation, a growing body of scientific evidence and a greater understanding of sustainability impacts. There is now a demand for companies to manage a wide range of issues in a systematic way, to improve performance and to be able to demonstrate this.

Designers and specifiers are demanding transparent, reliable data and comparable sustainability information about competing construction materials. Standard setting organizations and building rating systems are maturing in their requirements. Third-party certification bodies have responded with improved certification schemes that facilitate the provision of data collection, auditing and reporting. The CARES Sustainable Constructional Steel (SCS) scheme, which certifies reinforcing carbon and stainless steel, structural steel and hot rolled flat steel internationally, is a good example of such a scheme.

Developed with the inputs of a wide range of stakeholders, the accredited scheme is based on the foundations of technical specifications, traceability and product quality as well as the sustainability principles of inclusivity, integrity, stewardship and transparency. Specification of certified steels for reinforced concrete helps reduce detrimental and increase positive sustainability impacts across the construction industry value chain.


Document: 

SP283-1

Date: 

March 1, 2012

Author(s):

Rolf Eligehausen and Werner Fuchs

Publication:

Symposium Papers

Volume:

283

Abstract:

In the last 10 years there have been tremendous developments made in the strength of the adhesives and the fields of applications of adhesive anchor systems. Hence these systems are used for structural attachments in a wide variety of applications in concrete construction. Suitable products, careful selection and design, and proper installation are vital for the overall performance of a structural connection. While suitable products prequalified under provisions such as AC308 and ACI 355.4-10, and produced under strict quality control are or will be on the market – demonstrated by an Evaluation Service Report - and rational design models have been developed to ensure a reliable use of adhesive anchor systems in daily construction practice, the knowledge of the designers and installers in fastening technology is often not adequate. The knowledge of the designers should be updated regularly. Adhesive anchors should be installed by properly trained installers. However, the training of the installers needs to be improved significantly. The proper training should be demonstrated by a certificate that is issued by an independent agency after passing a corresponding test. The new ACI Anchor Installer Certification program that is currently under progress will fulfill this requirement.

DOI:

10.14359/51683757


Document: 

SP191-06

Date: 

December 1, 1999

Author(s):

D. Whiting and M. Nagi

Publication:

Symposium Papers

Volume:

191

Abstract:

A laboratory and field test program was undertaken to determine the perfromance of a nuclear water/cement content gauge for fresh concrete. The laboratory evaluations included study of the effects such variables as air content, pozzolans, hold time, coarse aggregate, and temperature on gauge response. The laboratory testing demonstrated that the gauge is sensitive to materials compositions and other factors, and therefore must be calibrated with exactly the same materials as will be used on the job in question. With proper calibration in a laboratory setting, the cement gauge is capable of determining cement content of fresh concrete to within approximately 10 to 20 lb/yd3 (6 to 12 kg/m3). The water gauge is capable of determining water content to within approximately 2 to 4 lb/yd3 (1 to 2 kg/m3). Field tests at two locations are described. Favorable results were acheived where calibrations were carefully carried out using the same materials as to be used in actual construction. In these cases, avearge water content determinations for a series of samples using the nuclear gauge were comparable to those obtained using a microwave oven drying technique.The gauge is well-suited for use at construction sites. Technicians (having proper radiation safety training and certification) can successfully operate the gauge after a brief period of training, and the gauge can be transported in construction vehicles and set up on-site with a minimum of effort. The test period is short, requiring approximately ten minutes per sample, including consolidating of concrete into a test bucket.

DOI:

10.14359/5735


Document: 

SP188-54

Date: 

August 1, 1999

Author(s):

T. Ando, E. Sawada, and K. Nii

Publication:

Symposium Papers

Volume:

188

Abstract:

New repair and maintenance technique for existing reinforced concrete structures has been developed as a result of a marriage of corrosion prevention and carbon fiber reinforced polymer (CFRP) installation techniques. Rebar corrosion prevention is basically provided by penetrating liquid and/or mortar, while mechanical degradation is compensated by CFRP. CFRP can also provide an effective protective layer for subsequent corrosive agent penetration. The technique can overcome various drawbacks of the current repair techniques by minimizing repair time and unnecessary chipping of damaged concrete, and protect degrading concrete structures. Such excellent performances have been proven by a series of experiments. Steel rebar embedded in a concrete block brushed with lithium nitrite-based penetrating corrosion inhibitor has been proven rust-free for years. The tensile strength of CFRP sheet have been proven unchanged after the exposure of 10,000 hours of accelerated weathering conditions. The CFRP sheet has also been proven impermeable to salt ion and water by experiments. Both shear and tensile strengths of concrete columns, damaged by salt penetration and then repaired with this new technique, have been proven equal or greater than the original strengths of control column. The performance of this technique has also been granted an official “Examination and Certification of Building Preservation & Maintenance Techniques” by the authorized organizations of the Ministry of Construction, Japan in July, 1998.

DOI:

10.14359/5658


Document: 

SP175-09

Date: 

December 1, 1998

Author(s):

L. Javier Malvar, Kevin P. Hager and James E. Tancreto

Publication:

Symposium Papers

Volume:

175

Abstract:

The Naval Facilities Engineering Service Center (NFESC) is developing a new ordnance storage magazine that will reduce encumbered land and improve operational efficiency. Energy absorbing walls using lightweight concrete are being developed to prevent sympathetic detonation between cased munitions stored in adjacent cells. Design loads, wall response, and wall effectiveness are predicted and compared to test results from one-third scale development tests and full scale demonstration and certification tests. Specially designed lightweight concretes (or chemically bonded ceramics, CBC’s) with high porosities in excess of 50% were used in the development program. The most efficient (cost and performance) barrier wall design utilizes a composite wall consisting of an exterior reinforced concrete cover and a heavy granular fill material. The CBC which makes up the cover has a strength of 2500 psi, a unit weight of 65 pcf, and a porosity over 50%. This CBC cover mitigates initial shock on impact with acceptors while the heavy granular fill reduces wall velocity (and kinetic energy), disperses momentum, and stops fragments. The exterior magazine walls, also constructed with lightweight concrete, reduce shock loads on impact by acceptor munitions.

DOI:

10.14359/5921


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