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 33 Abstracts search results

Document: 

20-210

Date: 

July 1, 2021

Author(s):

Tayseer Z. Batran, Mohamed K. Ismail, and Assem A. A. Hassan

Publication:

Materials Journal

Volume:

118

Issue:

4

Abstract:

This study investigated the structural behavior of lightweight self-consolidating concrete (LWSCC) beams strengthened with engineered cementitious composite (ECC). Four LWSCC beams were strengthened at either the compression or tension zone using two types of ECC developed with polyvinyl alcohol (PVA) fibers or steel fibers (SFs). Three beams were also cast in full depth with LWSCC, ECC with PVA, and ECC with SFs, for comparison. The performance of all tested beams was evaluated based on loaddeflection response, cracking behavior, failure mode, first crack load, ultimate load, ductility, and energy absorption capacity. The flexural ultimate capacity of the tested beams was also estimated theoretically and compared to the experimental results. The results indicated that adding the ECC layer at the compression zone of the beam helped the LWSCC beams to sustain a higher ultimate loading, accompanied with obvious increases in the ductility and energy absorption capacity. Higher increases in the flexural capacity were exhibited by the beams strengthened with the ECC layer at the tension zone. Placing the ECC layer at the tension zone also contributed to controlling the formation of cracks, ensuring better durability for structural members. Using ECC with SFs yielded higher flexural capacity in beams compared to using ECC with PVA fibers. The study also indicated that the flexural capacity of single-layer and/or hybrid composite beams was conservatively estimated by the ACI ultimate strength design method and the Henager and Doherty model. More improvements in the Henager and Doherty model’s estimates were observed when the tensile stress of fibrous concrete was obtained experimentally.

DOI:

10.14359/51732635


Document: 

19-461

Date: 

May 1, 2021

Author(s):

Anuj Gupta and Harishchandra Thakur

Publication:

Materials Journal

Volume:

118

Issue:

3

Abstract:

The present study investigates the impact of agro-green waste as an additive to concrete composition. The objective of the investigation is to evaluate the impact of agro-waste material as a thermal insulator for buildings. It helps in the reduction of energy consumption inside buildings. Wheat straw, rice husk, and coconut coir are used for the preparation of the composite concrete mixture. With a decrease in thermal conductivity and an increase in compressive strength, this paper provides a possibility of agro-waste in the concrete industry.

DOI:

10.14359/51730421


Document: 

18-192

Date: 

March 1, 2019

Author(s):

Meysam Najimi and Nader Ghafoori

Publication:

Materials Journal

Volume:

116

Issue:

2

Abstract:

The current study aims to assess the transport and durability properties of alkali-activated concretes made with hybrid aluminosilicate precursors having different proportions of natural pozzolan as a low-calcium precursor and ground-granulated blast furnace slag as a high-calcium precursor, which are activated with different concentrations and combinations of sodium hydroxide and sodium silicate. The studied parameters included precursor combination (natural pozzolan/slag combinations of 30/70, 50/50, and 70/30), sodium hydroxide concentration (1, 1.75, and 2.5 M), and activator combination (sodium hydroxide/sodium silicate combinations of 70/30, 75/25, and 80/20). The resulting concrete mixtures were tested for slump flow, setting time, compressive strength, absorption, rapid chloride penetration, rapid chloride migration, resistance to sulfuric acid attack, chloride-induced corrosion, and frost resistance. Mercury intrusion porosimetry and X-ray diffraction were used to justify the observed behaviors. The performance of alkali-activated natural pozzolan/slag concretes was also compared with that of a reference concrete made with solely portland cement binder. In view of overall performance, an equal proportion of natural pozzolan and slag (50/50) and a 30/70 combination of sodium silicate and sodium hydroxide proved to be the optimum precursor and activator combinations. The optimum sodium hydroxide concentration was dependent on the precursor and activator combinations as well as the expected fresh, strength, transport and durability performance. In terms of the measured transport properties (that is, absorption, chloride penetration depth, and passing charges) and resistance to acid attack and chloride-induced corrosion, all the studied alkali-activated concretes performed considerably superior to the reference portland cement concrete. In the case of frost resistance, only alkali-activated concretes with 50 and 70% slag performed superior to the reference portland cement concrete.

DOI:

10.14359/51714455


Document: 

17-432

Date: 

January 1, 2019

Author(s):

Qi Cao, Quanqing Gao, Jinqing Jia, and Rongxiong Gao

Publication:

Materials Journal

Volume:

116

Issue:

1

Abstract:

To improve the early-age cracking resistance of self-consolidating concrete (SCC), this paper investigated the effects of an expansive agent (EA), fibers, and the interaction between EA and fibers on the cracking behavior of restrained SCC caused by plastic shrinkage based on the slab test. Twenty-one types of samples were prepared, including one control group, two EA contents (6 and 8% of the mass fractions of cementitious materials), three steel fiber contents (0.25, 0.50, and 0.75% by volume), three polypropylene fiber contents (0.05, 0.10, and 0.15% by volume), three hybrid fiber contents, and nine combinations of EA (8% of the mass fraction of cementitious materials) and fibers. The initial cracking time and propagation of cracks over time were both observed. Test results indicate that an increase of EA dosage presents no significant improvement on early-age cracking resistance capability. Compared with steel fiber (SF), polypropylene fiber (PP) with equivalent fiber factors was particularly effective in reducing the nominal total crack area. In general, crack reduction factors of fiber-reinforced expansive self-consolidating concrete (FRESCC) are 70% greater than that of SCC containing fiber only. It indicates that the combination of EA and fibers enable SCC to present better early-age cracking resistance.

DOI:

10.14359/51710957


Document: 

17-129

Date: 

January 1, 2018

Author(s):

M. Abdur Rasheed and S. Suriya Prakash

Publication:

Materials Journal

Volume:

115

Issue:

1

Abstract:

This paper presents the stress-strain behavior of structural synthetic fiber-reinforced cellular lightweight concrete (CLC) stack-bonded prisms under axial compression. Masonry compressive strength is typically obtained by testing stack-bonded prisms under compression normal to its bed joint. CLC prisms with cross-sectional dimensions of 200 x 150 mm (7.87 x 5.90 in.) with an overall height of 470 mm (1.54 ft) were cast with and without different dosages of synthetic fiber reinforcement. Polyolefin was used as a structural fiber reinforcement at different volume fractions (vf) of 0.22, 0.33, 0.44, and 0.55% with and without microfiber dosage of 0.02%. Experimental results indicate that the presence of fibers helps in the improvement of strength, stiffness, and ductility of CLC stackbonded prisms under compression. Test results also signify that the hybrid fiber reinforcement provides better crack bridging mechanism both at micro and macro levels when compared to only macrofibers. Simple analytical models were developed for stress-strain behavior of CLC blocks and stack-bonded CLC prisms based on the experimental results with and without fibers under compression.

DOI:

10.14359/51701241


12345...>>

Results Per Page 




Please enter this 5 digit unlock code on the web page.