Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : Cement

Mitigation of the Factors Affecting the Autogenous Shrinkage of Ultra-High Performance Concrete

Adil M. Jabbar; Mohammed J. Hamood; Dhiyaa H. Mohammed

Engineering and Technology Journal, 2021, Volume 39, Issue 12, Pages 1860-1868
DOI: 10.30684/etj.v39i12.2155

Ultra-High Performance Concrete (UHPC) is a new generation of concrete characterized by its high strength, high durability, and high stiffness. Autogenously shrinkage represents one of the issues of UHPC that occurred at early ages. It occurs particularly during the first 48 hours after casting. This paper focuses on the ways that can be depended on to mitigate the autogenously shrinkage and obtain the outstanding mechanical properties of UHPC. The results showed that the use of coarse sand and high dose of high range water reduced the admixture above 5% of cementations of materials weight, and high ambient temperature at the time of mixing and casting led to increasing the autogenously shrinkage. While using fine sand, silica fume at 25% of cement weight, and crushed ice at 50% of mixing water to control the mixing temperature can reduce autogenously shrinkage significantly.

Study The Effect of Traditional Iraqi Stabilizers (Cement and Lime) on Some Properties of Iraqi Clay Soils

Husam H. Baqir; Aqeel Sh. Al-Adili; Ali H. Shareef

Engineering and Technology Journal, 2018, Volume 36, Issue 3A, Pages 248-255
DOI: 10.30684/etj.36.3A.2

This study provides practical results in the use of the composite from sulfate resistance Portland cement (PC) and Quicklime (LQ) to improve and stabilize of soils in Al - Zaafaraniya site in Baghdad governorate and the Garma Ali site in Al Basra governorate, Iraq. PC and LQ were added in percentages of 2,4,6,8 and 10% and 2 and 4%, by dry weight, respectively. Laboratory tests to determine Atterberg,s limits, standard proctor test, USC test and UUU test (unconsolidation, undrained and unsaturated) were conducted. The results achieved a significant improvement in workability, unconfined compressive strength and shear strength. The results of the unconfinedicompressiveistrength test and UUU test for natural and improved soil reveal that the shear strength increase as lime and cement content increase and with increasing curing (0, 7 and 28)days.

Effect of Fibers on Some Engineering Properties of Cement and Lime Stabilized Soils

Suhail A. Khattab; Ibrahim M. Al-Kiki; Abderrahmane H. Al-Zubaydi

Engineering and Technology Journal, 2011, Volume 29, Issue 5, Pages 886-905

Recently, many attempts were made to use metal fiber reinforcements to
improve some soil properties. In this research, the effects of fibers on the
compaction and mechanical properties of cement and lime stabilized soils (silty
and clayey soils respectively) were studied. Variables such as stabilizer (cement
and lime) content, amount and type of metal fibers were studied. Results indicated
that the addition of fibers lead to increase in the maximum dry unit weight. On the
other hand, a maximum values of unconfined and tensile strength were obtained
with the addition of 0.5 % short fiber (FS) and 1.5 % long fiber (FL) respectively.
During the flexural test a brittle manner failure was observed for the unreinforced
samples and samples prepared with little amount of fibers 0.5%. Finally, the
addition of fibers increases the fracture energy of cement stabilized silty soil and
lime stabilized clayey soil.