مشروع البحث: تاتير أساليب وزمن الدمك علي الكثافة ومقاومة الخرسانة للضغط
تحميل...
المساهمين
الممولين
رقم التعريف
6962
الباحث
محمد الامين مفتاح موسي
الوصف
Concrete is one of the most widely used construction materials in the field of construction. During the past years, there has been a great development that contributed to the construction of various concrete buildings. Despite the development of concrete stages, there are still some problems facing the various of concrete stages.
This study reviews the effect of methods and compaction time on density and compressive strength of concrete, for a concrete mix without chemical admixture, and used different methods of compaction (manual compaction, mechanical compaction) ,with different compaction periods 0, 5, 10, 15 , 20, 25, 30 seconds. The percentage of water cement ratio was changed in the mixture. The percentage of aggregates cement ratio was also changed and the slump test has done in each case. All samples were cured by Immersion in water for 7, 14 and 28 days .
Results of this study show that , the procedure of concrete compaction has an effect on the density and compressive strength, and the mechanical compaction is more efficient than the manual compaction .The results obtained and confirmed by some previous studies[1],Shows that compressive strength of the Concrete increases gradually by increasing compaction time ,and compressive strength reaches a peak on certain compaction time , then decreases if we continue compaction , and occur which called bleeding and segregation[2]. As for density of concrete it was observed through this study that when concrete was cast and left to harden without compaction, resulting a concrete of low density, and as a result of increasing compaction time , density increases. Changing of water cement ratio also has an effect on compaction time of concrete ,the more water cement ratio, the less time for compaction, on the other hand, lower water content, concrete needs more compaction time to get required density and compressive strength . water cement ratio is also fixed in the reference mix and the percentage of aggregates was reduced. When the aggregate content is reduced, the time required for compaction is reduces, and the increase of aggregate cement ratio needs more compaction time to get the required specifications for concrete
الكلمات الدالة
الكثافة ، مقاومة الضغط