Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : modulus of rupture


Effect of Practical Curing Methods on the Properties of Roller Compacted Concrete

Hisham K. Ahmed; Intesar Kadhim Gata

Engineering and Technology Journal, 2015, Volume 33, Issue 2 engineering, Pages 500-511
DOI: 10.30684/etj.2015.101919

Roller Compacted Concrete (RCC) is a technology characterized mainly by the use of rollers for compaction. This construction method permits considerable reduction in costs and construction time of dams and roads. It is necessary to study the curing of RCC especially in hot weather because RCC has no slump and has low W/C ratio. Therefore the primary scope of this research is to study the effect of various curing methods (continuous watering, wet burlap, nylon, sprinkling, curing cycles, and curing compound) after 24 hrs from casting on the physical properties of roller compacted concrete.
The mix proportion which was used in this investigation, was designed and laboratory tried on the basis of using 250 kg/m³ of Ordinary Portland Cement. This work involves preparing cylindrical specimens with (diameter of 150 mm and height of 300 mm) for measuring the compressive strength, splitting-tensile strength, and static modulus of elasticity. And it also includes prism specimens with (100×100×400 mm) for measuring the modulus of rupture (flexural strength).
Results show that the curing of RCC with continuous watering clearly improved the RCC properties. The results also indicate that the RCC specimens without curing (left in air) suffered from permanent loss of strengths ranging between 20 to 25 % when compared with continuous watering at age of 28 days.

Mechanical Properties of High-Strength Fiber Reinforced Concrete

Zaid Muhammad Kani Al-Azzawi; Kaiss Sarsam

Engineering and Technology Journal, 2010, Volume 28, Issue 12, Pages 2442-2453

Experimental results of this work in addition to a wide range of data from previous work
were analyzed to study the mechanical properties and strength of high-strength concrete with and
without fibers. Different types of steel fibers (straight, hooked, duoform, crimped) with a volume
fraction ranging from 0 to 2 percent were studied. The concrete compressive strength ranged from 41
to 115 MPa. The influence of fiber on the compressive strength, axial strain, modulus of elasticity,
Poisson's ratio, modulus of rupture, and splitting tensile strength, were studied. In addition to that,
size effect of control specimens on high-strength fiber reinforced concrete materials, was observed.
The main conclusion indicates that high-strength concrete (HSC) properties, especially with fibers
are significantly different from normal-strength concrete (NSC).