A Study into the Qualities of Concrete

made with Coarse Aggregate obtained from Selected Quarry Sites in Anambra State, Nigeria

 

FEATURED PAPER

By Fidelis O. Ezeokoli, Chiagozie B.N. Bert-Okonkwor, Chukwuebuka I. Onyia

Department of Building
Nnamdi Azikiwe University

Awka, Anambra State, Nigeria

 


 

ABSTRACT

The study examined the qualities of coarse aggregate sourced from different quarry sites within Anambra State, Nigeria. Samples for this study were obtained from quarry sites at Enugwu-Ukwu, Aguleri, Nsugbe, Nkwelle –Ezunaka and Ogbunka. The study carried out sieve analysis test, slump test and cube (crushing strength) using the samples obtained from the listed quarry sites. From the test, the study observed that the crushing/compressive strength of the samples at 7 day are between 20-29N/mm2 with Ogbunka samples having the highest compressive strength of 29.33N/mm2. Thus, at 7th day, four out of the five samples tested attained the minimum strength of concrete (i.e. 21N/mm2). Also, the study observed that the percentage of slump ranges from 21.5 – 41% with Nsugbe samples having the best slump value of 21.5%. The study observed that the samples were fairly graded. The percentage of the grains passing through 19.05 diameters is between 64.3 – 84.0%. The study concluded by recommending that stones should be properly graded and properly washed before utilization since most of them are coated with impurities which may interfere with the process of bonding.

1.0 INTRODUCTION

Concrete is a major component of infrastructural facilities in the 21st century because of its versatility in use. Concrete is used more than any other man-made material in the world (Anosike, 2011). Concrete is a composite construction material, composed of cement (commonly Portland cement) and other cementitious materials such as ‘fly ash’ and ‘slay cement’, aggregates (overall coarse aggregate made of gravel or crushed rocks such as limestone, or granite plus fine aggregate such as sand), water, and chemical admixture, (Bert-Okonkwor, 2012). Based on its properties i.e strength, rigidity and easy formability, coupled with the easy availability of the component materials, have made concrete the material of choice for architects, engineers, builders and developers. The three-basic component of concrete – cement, aggregate and water greatly affect the quality of concrete (Duggal, 2008). In-furtherance, Duggal (2019) stated that aggregate occupy about 70-80 percent of the volume and thus considerably influence the properties of the concrete. In line with this, UNESCO-Nigeria Technical & Vocational Education Revitalisation Project-Phase II (UNESCO-NT&VERP II), (2008) opined that “The compressive strength of concrete cannot exceed that of the aggregate used therein.”

Aggregates as defined by UNESCO-NT&VERP II, (2008) are “materials comprising of percentage required of gravel, crushed stone and natural sharp sand of their specific size of particle mixed together at a required ratio to form part of concrete mortar.” To Council of Registered Builders of Nigeria (CORBON) and Nigeria Institute of Building (NIOB), (2014), Aggregates are the granular filler material such as sand, stone dust, gravel, crushed stone, crushed blast-furnace slag, etc. that are used with binder such as Portland cement to produce concrete or mortar. Ezeokonkwo (2014) also described aggregates as inert or chemically inactive materials which form the bulk of cement concrete and are bound together by means of cement as a binder. Aggregate used in construction basically comes in two different sizes—the bigger ones known to be coarse aggregate (grit) and the smaller one’s – fine aggregate (sand) (Ezeokonkwo, Okolie & Ogunoh, 2015). Furthermore, Ezeokonkwo, Okolie and Ogunoh, (2015) stressed that coarse aggregate form the main matrix of concrete and the fine aggregate form the filler matrix between the coarse aggregate. Since up to approximately 80 percent of the total volume of concrete consists of aggregate, aggregate characteristics significantly affect the performance of fresh and hardened concrete and have an impact on the cost effectiveness of concrete (Quiroga & Fowler, 2003). Aggregate characteristics of shape, texture, and grading influence workability, finishability, bleeding, pumpability, and segregation of fresh concrete and affect strength, stiffness, shrinkage, creep, density, permeability, and durability of hardened concrete. Construction and durability problems have been reported due to poor mixture proportioning and variation on grading (Quiroga & Fowler, 2003).

Conversely, failures of concrete can sometimes be mild with visible cracks and deflections or severe crack, leading to partial or total collapse of the structure either during the construction or post- construction stage. Incidences of failures of structures linked to bad concrete practice are abounding in Nigeria particularly in our major cities such as Lagos, Port-Harcourt, and Abuja, among others (Ezeokonkwo, 2014). The findings of the committee of enquiry that investigated the collapsed four-storey building at Okpuno, Awka, Anambra state capital in September 2008 reported that the building collapsed the same day the casting of the concrete third floor slab was concluded revealed that the main causes of the collapse was the use of sub- standard materials particularly coarse aggregates used for concrete production. In order to curb the incidence of building collapse across the globe, several researches have been carried out at different time by different individuals, corporate bodies and civic society to ascertain the strength and/or quality of materials used in concrete production. Attention mainly is placed on reinforcements and cements, with little on the aggregates. In continuation, little research has been made in order to establish the quality of the coarse aggregate sourced within study area. Therefore, this study examined the qualities of coarse aggregate sourced from different quarry sites within study area, with a view to determining their suitability for concrete production. The study identifies and obtained samples of coarse aggregate from the different quarry sites within the study area. Also, the study carried out laboratory experiment to ascertain the compressive strengths, aggregates particle size distribution and slump test for the various samples.

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How to cite this paper: Ezeokoli, F.O.; Bert-Okonkwor, C.B.N.; Onyia, C.I. (2019). A Study into the Qualities of Concrete made with Coarse Aggregate obtained from Selected Quarry Sites in Anambra State, Nigeria; PM World Journal, Vol. VIII, Issue VI, July.  Available online at https://pmworldlibrary.net/wp-content/uploads/2019/07/pmwj83-Jul2019-Ezeokoli-Bert-Okonkwor-Onyia-study-of-concrete-qualities-in-Anambra-State.pdf

 


 

About the Authors


Dr. Fidelis O. Ezeokoli

Awka, Anambra State, Nigeria

 

 

 

Dr. Fidelis O. Ezeokoli is a Lecturer in the Department of Building, Nnamdi Azikiwe University with vast experience in building construction and management. He has successfully delivered a number of building projects to time, desired quality and within the client’s budget. He holds a B.Sc., M.Sc. PhD degrees in Building, Construction Management and Construction Management respectively from Nnamdi Azikiwe University, Awka. His research interests are in flood resilient buildings, building materials; construction management; ICT in construction and project management. He is a member of the Nigerian Institute of Building (MNIOB). You can reach him on okeyezeokoli@gmail.com or okeyezeokoli@unizik.edu.ng

 


Chiagozie B. N. Bert-Okonkwor

Awka, Anambra State, Nigeria

 

 

 

Chiagozie B. N. Bert-Okonkwor is a Lecturer in the Department of Building, Nnamdi Azikiwe University with vast experience in building construction and management. He has successfully delivered a number of building projects to time, desired quality and within the client’s budget. He holds a Bachelor of Engineering and Master of Science degrees in Civil Engineering and Construction Management respectively from Nnamdi Azikiwe University, Awka. He is presently rounding off his PhD programme in construction management from same institution. His research interests are construction technology, soil mechanics and foundations, structures, concrete technology, construction management. You can reach him on eizoga234@yahoo.com

 


Chukwuebuka I. Onyia

Awka, Anambra State, Nigeria

 

 

Chukwuebuka I. Onyia is a visiting lecturer in the Department of Quantity Surveying, Institute of Management and Technology Enugu. He holds a B.Sc. and M.Sc. degree in Quantity surveying and Construction Management respectively. He is presently running a PhD programme in construction management, Nnamdi Azikiwe University, Awka. His research interests are in Quantity surveying, cost and construction management, estimating and construction tendering. He is a member of the Nigerian Institute of Quantity Surveying (MNIQS). You can reach him on mailonyia@ymail.com