Print ISSN: 1813-0526

Online ISSN: 2220-1270

Main Subjects : Structures


A Review on Mix Design of Self-Compacting Concrete

Nuha H. Al_jubory; Tuqa Waleed Ahmed; Roua Suhail Zidan

Al-Rafidain Engineering Journal (AREJ), 2020, Volume 25, Issue 2, Pages 12-21
DOI: 10.33899/rengj.2020.126727.1017

In recent years, the use of self-compacting concrete in structures has increased significantly around the world
Many studies have been carried out on the characteristics of this type of concrete with the urgent need to design concrete mix and to find the material ratios used in this type of concrete so far there are no standard mix design self-compacting concrete methods, but there are many types of research to design mixes. Hence the need to review and compare these methods is of considered interest. The review of these studies helps researchers to choose the appropriate method of designing the mixtures of self-compacting concrete and their requirements, whether the strength or workability requirements.

Strengthening and Rehabilitation of Concrete Prisms Using GFRP Sheets

Ashtar S. Al-Luhybi; Bayar J. Al- Sulayfani

Al-Rafidain Engineering Journal (AREJ), 2020, Volume 25, Issue 1, Pages 17-23
DOI: 10.33899/rengj.2020.126531.1008

The use of external strengthening by fiber reinforced polymer (FRP) technology has significantly increased in recent decades. This is because (FRP) has the properties that make it the most suitable option for strengthening and rehabilitation of damaged concrete structures instead of using traditional materials such as steel plates. In this paper, the behaviour of non-reinforced concrete beams externally wrapped with Glass Fiber Reinforced Polymer (GFRP) sheets has been examined. Fourteen unreinforced concrete prisms were cast with a rectangular section of (150 × 125 mm) and a length of (760mm), these specimens were divided into five group. First group was not externally wrapped with GFRP sheets (control specimens), and the remaining groups were GFRP wrapped with a variable number of GFRP layers (thickness of wrapping). In the first stage of study, the prisms have been tested and the effect of external wrapping and increasing the wrapping thickness on the behaviour of prisms was observed. In the second stage, the unwrapped concrete prisms that were tested and failed (control specimens) were rehabilitated by externally wrapping them with one layer of GFRP sheets. The results have shown that wrapping with GFRP sheets increased the capacity of the prisms and failure load had reached to (342.5%) for prisms wrapped with three layers when compared to the control specimens. It was also noticed that there was an increase in the toughness of the prisms by increasing the number of GFRP layers. The results have shown that there was a decrease in the failure load of the four layer wrapped prisms, and this was due to the early failure of the prisms due to the debonding of the GFRP sheets from the prism surface. The damaged specimens which were later rehabilitated have shown an increase in load carrying capacity compared to the control specimen.