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Roller Compaction Concrete

Self-healing concrete also called bioconcrete is a type of concrete which  possesses the ability [ ... ]

INTRODUCTION:

Roller Compaction Concrete (RCC) also refers to (Rollcrete) or (Rolled Concrete), now a days this two names are not commonly used in books and daily activity in construction site, the term of roller compacted concrete that the concrete is compacted by roller as used in asphalt pavement, mechanical properties of this concrete its almost similar to conventional placing of concrete, despite the concrete mixture it should be different. Mixture of this concrete should be as much as stiff and dry to support the weight of roller and other equipment's used in construction, mixture slump it should be less than zero.paving style is almost similar to asphalt pavement because in roller compacted concrete usually paving machine was used to pave the concrete into specific depth, then concrete compacted by heavy dual-drum steel wheel roller, pneumatic tire roller is not used because concrete properties are different than asphalt.

 

The main advantage of this roller compacted concrete is cost effective, no need for molds and formwork this could save time, less labor require, and paving process is finish in one day and the road is almost ready for traffic.

American Concrete institute (ACI) in Cement and Concrete Terminology (ACI 1 16R-90) define Roller Compaction Concrete (RCC) as "Concrete compacted by roller compaction; concrete that, in its unhardened state,will support a roller while being compacted".

 

Fig.1:  Roller compaction concrete

HISTORY OF ROLLER COMPACTION CONCRETE:-

Roller compaction concrete was developed mainly for dam construction, to complete concrete dam rapidly because of fast paving process, and its considered as a lower-cost alternative for earth or rock fill dam, and this concrete was become the alternative method for conventional concreting in dam construction industry, Fig-2 show dam construction project constructed by roller compaction concrete. the main idea behind developing and inventing roller compaction concrete when cement mixed with soil to improve the shear strength, and the mixture of soil and cement (some times called cement treated base) compacted by rollers, and they notice that the result quite good for improvement and soil shear strength is much higher than before.

The Japan was the first user of roller compacted concrete for construction core of dam body in (Shimajigawa)started in 1978. The first use of RCC for construction full dam body in United States, RCC used for (Willow Creek) dam constructed by U.S. army corps and engineering in 1982, "Approximately 330,000 m3 or RCC" was placed in this 50 m high dam in less than 5 months.

 

 

Application and Advantages:-

Mass RCC can be applicable any where where conventional concrete was used, mainly RCC used for construction of concrete dams, according to previous construction information, the cost of construction as much as lower than using conventional concrete for about 15% to 30%, that is why RCC is economy, another important advantage is time saving, construction process is to fast and whole body of dam can be construction on one construction season, the whole process require less labor force.

Fig.2: Dam construction by using roller compaction concrete

 

Types of RCC:-

According to location of using RCC, there is two category can be selected:

1- Low Cement Content:- when strength is not main requirement and heat rise is a critical issue specially in mass concreting, RCC can be used for massive structure such as dams, levees, retaining walls,etc.).

2- High Cement Content:- When strength is a main criteria, and the concrete should resist to impact and have abrasion resistance, high cement content was used, this one due to heat rises used for thin section such as a pavement.


REFERENCE:-

1- Joseph A. Dobrowolski, 1998. Concrete Construction Handbook. 4th edition, New Jersy: McGraw-Hill, PP 27.3.

2- CivilFerba (www.civilferba.net)

 

About Aci-Kurdistan Chapter

The ACI chapter of Kurdistan is a recently establisehd branch of ACI, which cover the geographic region of the southern kurdistan which so called (Iraqi Kurdistan region). The main goal of the chapter is to merge our knowledge about the concrete with the most recent standards and specifications. Also, the Kurdistan chapter makes a strong tie between the universities across the Kurdistan region.

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