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Challenge Journal of Concrete Research Letters
Number of Followers: 6

This is an Open Access Journal

Open Access journal
ISSN (Online) 2548-0928
Published by TULPAR Academic Publishing

[2 journals]

Cover & Contents Vol.9 No.2
- Authors: CJCRL Journal Management
  PubDate: 2018-06-08
  Issue No: Vol. 9, No. 2 (2018)
Cover & Contents Vol.9 No.1
- Authors: CJCRL Journal Management
  PubDate: 2018-04-03
  Issue No: Vol. 9, No. 2 (2018)
Standardization the effect of shape of aggregates with respect to
compressive strength of concrete
- Authors: Md. Shafiqul Islam, Md. Abul Kalam Azad, Arup Ratan Sarker
  Pages: 1 - 9
  Abstract: It is proved that aggregate’s types have the severe effect on physicomechanical properties of concrete as aggregate covered almost 70 to 80 percent of the total volume of concrete. The effect of Flaky and Elongated aggregates on strength, durability, and workability of concrete has often been qualitatively expressed. The aim of this work is establishing the same quantitatively. M25 grade concrete for different ratios of weights of Elongated to normal aggregate, Flaky to normal aggregate and combined Flaky & Elongated aggregate to normal aggregate was tested for compressive strength at 28 days concrete. Three different types of aggregates were employed in the investigation, namely; normal aggregate, Elongated aggregate, and Flaky aggregate. Density and water absorption also kept constant to identify the effects on properties of concrete only for differences in shape. Thirty-six concrete cylinder was cast at 28 days. Varying dosages of Normal aggregate (60%, 65%, 70%, 75%,80% 85%), flaky aggregate (40%, 35%, 30%, 25%, 20%, 15%), elongated aggregate (40%, 35%, 30%, 25%, 20%, 15%), by mixture volume and length of 12inch (304.8 mm) & diameter of 6inch (152.4 mm) cylinder were used to test. Compaction was done by temping rod. Concrete cylinder was tested at the age of 28 days of curing. This study proposed of mixing three different types of aggregate in concrete. Compressive strength of concrete was measured by the effect of three different shapes of aggregates of varying dosages.
  PubDate: 2018-04-03
  DOI: 10.20528/cjcrl.2018.01.001
  Issue No: Vol. 9, No. 2 (2018)
Production of durable high strength flowable mortar reinforced with hybrid
fibers
- Authors: Eethar Thanon Dawood, Mahyuddin Ramli
  Pages: 10 - 20
  Abstract: This study deals with the production of durable high strength flowable mortar (HSFM). Firstly, the optimum percentage of silica fume was determined due to Pozzolanic Activity Index (P.A.I) test. Secondly, the selected mortar reinforced by different percentages of steel fibers or hybrid fibers of steel fibers , palm fibers and synthetic fibers (Barchip) to prepare HSFM mixes. Such mixes were tested in compressive strength, splitting tensile strength, static modulus of elasticity, flexural strength, toughness indices determination, and impact load for all the mixes. Lastly, the effects of seawater exposure on the properties of HSFM have been observed. The results show that the use of 10% silica fume as a partial replacement of cement indicate the best P.A.I. On the other hand, the hybridizations of such fibers enhance the performance of HSFM mixes. In addition, the hybrid fibers reduce the permeability of HSFM leading to significance improvement against seawater exposure.
  PubDate: 2018-04-03
  DOI: 10.20528/cjcrl.2018.01.002
  Issue No: Vol. 9, No. 2 (2018)
Effect of freezing-thawing on concrete behavior
- Authors: Zeinab A. Etman, Tamer I. Ahmed
  Pages: 21 - 36
  Abstract: This study aims to determine the effect of change of temperature (freezing-thawing cycles) on the behavior of the mortar and the concrete. Also, the evaluation of the effect of air entering for improving the durability of the mortar and concrete was discussed. 23 mixes were cast to evaluate the purpose of this study. Cement types (Portland cement and limestone cement), aggregate types (dolomite and gravel), dosages of air entering 0.01, 0.1, 0.15 and 0.2% of cement weight and freezing thawing cycles (50, 100, 150, 200, 300 and 400 cycles) were considered. Relative dynamic modules of elasticity which is illustrated the internal cracks growth, durability factor and losses of weight were evaluated. Empirical correlations were formulated. The results showed that; 0.15% air entrained of cement weight improve the durability in term of freezing-thawing; where the durability factor for the mixes was ≥ 85% that exposed to freezing-thawing cycles in range 0-200. Up to 200 cycles of freezing-thawing cycles did not effect on the compressive strength of the mixes and the durability of the mortar and the concrete. It is recommended that more than 300 freezing-thawing cycles must be avoided.
  PubDate: 2018-04-03
  DOI: 10.20528/cjcrl.2018.01.003
  Issue No: Vol. 9, No. 2 (2018)
Experimental and numerical study of the behavior of RC slabs with openings
reinforced by metal mesh under impact loading
- Authors: Yousry B. I. Shaheen, Ghada Mousa Hekal, Ahmed Khaled Fadel
  Pages: 37 - 51
  Abstract: The main objective of the following work is to inspect the effect of reinforcing metal mesh on the behavior of slabs with openings under impact loadings. Based on an earlier numerical study by Shaheen et al. (2017), slabs with mid-side openings revealed the worst behavior regarding to deflection and cracked pattern when subjected to impact loading compared to other slabs with different locations of openings. Hence, the present work focuses specifically on this type of slabs and the variation in their behavior when reinforced by welded or expanded metal mesh. Seven specimens were prepared and tested in Faculty of Engineering, Menoufia University, Egypt. Moreover, a FE model for the slabs was built using Abaqus 6.14 and verified against test results. It was found that expanded metal mesh had a significant effect on reducing deflection due to impact load as well as controlling of cracks in contrast with welded metal mesh.
  PubDate: 2018-06-08
  DOI: 10.20528/cjcrl.2018.02.001
  Issue No: Vol. 9, No. 2 (2018)
Prediction of self compacted rubberized concrete properties using Taguch
methods
- Authors: Mohamed Safaan, Fatma Mohamed Eid, Amal A. Nasser, Mohamed Emara
  Pages: 52 - 61
  Abstract: The effect and optimization of using self-compacting rubberized concrete was investigated by using Taguchi method. Design of experiment was performed via orthogonal array to accommodate four factors with four levels. These factors were the percentage of fine rubber, coarse rubber, fly ash and viscocrete in the concrete mix. The signal-to-noise (S/N) ratio and the analysis of variance (ANOVA) were employed to study the performance characteristics of self-compacting rubberized concrete (SCRC). Rubberized concrete can be improved using the concrete proportioned as self-compacting concrete. The results indicate that there was a reduction in the strength with increasing rubber content but there was an increase in impact resistance. However, the replacement of 10% of coarse aggregate with coarse rubber gave more strength than that of zero rubber mix by 124% at 90 days. Replacement of 20% of both fine and coarse aggregates with fine and coarse rubber respectively, increased impact resistance by 453% compared to the corresponding SCRC control mix.
  PubDate: 2018-06-08
  DOI: 10.20528/cjcrl.2018.02.002
  Issue No: Vol. 9, No. 2 (2018)
Reinforcement corrosion in coastal and marine concrete: A review
- Authors: Saha Dauji
  Pages: 62 - 70
  Abstract: Concrete is used as a structural material for construction of buildings, jetties, harbors, etc. in many coastal and marine locations. The reinforcement used in concrete is susceptible to corrosion, resulting in loss of steel area, loss of bond, expansion of the reinforcement volume leading to cracking or spalling of concrete. Marine environment induces higher corrosion of reinforcement, compared to in-land locations. Concrete exposed to tidal fluctuations, or to the action of waves and currents are among the most severely affected. Corrosion of reinforcement in concrete is of major concern in coastal and marine environment. Control and monitoring of corrosion is a big challenge to engineers. In the recent years, different investigators reported their studies in this area. Depending on the severity of the exposure conditions, different corrosion inhibitors and protection methods have been attempted with varying degrees of success. The present article presents a generic review of the corrosion issues in marine concrete. Drawing from the experiences of the various researchers, the corrosion measurements, and corrosion control schemes, including use of coated reinforcements and corrosion inhibitors are discussed. The durability performance based design of concrete in the probabilistic framework and the life cycle cost analysis for durability design decisions have been identified as the future direction of corrosion protection of coastal and marine structures.
  PubDate: 2018-06-08
  DOI: 10.20528/cjcrl.2018.02.003
  Issue No: Vol. 9, No. 2 (2018)