The Department of Civil Engineering awarded a Ph.D. degree in the field of building materials engineering to the student (Iman Kattoof Harith) on 24/5/2022 at the postgraduate hall in the department for her tagged research:

“Innovative of nano-modified concrete mixed, placed and cured at hot/dry application in summer periods”

The discussion committee consisted of:

1- Prof. Dr. Wasan Ismail Khalil                                                                 President

2- Prof. Dr. Nada Mahdi Fawzy                                                                   Member

3- Prof. Dr. Muhammad Mansour Kazem                                                    Member

4- Asst. Prof. Dr. Qais Jawad Frayyeh                                                         Member

5- Asst. Prof. Dr.  Ali Attiea Jaber                                                               Member

6- Prof. Dr. Maan Salman Hassan                                        Member and Supervisor

7- Asst. Prof. Dr. Shatha Sadiq Hasan                                  Member and Supervisor

One of the most problems that face concrete production in Iraq and various countries in the Middle East is hot weather concreting. For example, in Iraq, the temperature reached 50°C in the summer season, therefore, the construction season is shortened by at least two months (July-August). Several international standards have recommended specific precautionary cooling measures to reach the maximum acceptable temperature of recently mixed concrete, in target to avoid adverse effects on concrete. The main objective of the study is to reveal the effects of cooling via using liquid nitrogen on the soft and hardening properties of concrete as well as the microstructure of hardened concrete. Multiple concrete mixtures with different pozzolanic materials were produced, poured, and cured at high temperatures (40 - 45oC) pointing to uses in hot summer periods in most regions of Iraq. The design of the experiment's approach was followed to evaluate the efficiency of liquid nitrogen in improving the properties of fresh and hardened concrete against other alternatives. Considered independent variables were fly ash, nano-silica, and liquid nitrogen. Pouring concrete at high temperatures weather requires the use of up to 276 liters / m3 of liquid nitrogen to reduce the concrete temperature by 20 degrees Celsius. The results showed that liquid nitrogen considerably improved the whole fresh and hardened properties of concrete mix produced at high temperatures.