Download Limestone Characteristics for Concrete Production in Jamshoro, Sindh, Pakistan and more Study Guides, Projects, Research Engineering Geology in PDF only on Docsity!
Engineering Geological Characteristics of limestone Types
For Concrete Production in Jamshoro Sindh , Pakistan
MUSHTAQUE AHMED PATHAN, RAFIQUE AHMED LASHARI,
SHABIR AHMED ABBASI, MARYAM MAIRA PATHAN.
( C P & A GEOLOGY, U o S JAMSHORO)
Cell No. 00923362401532
Abstract
The production of concrete in PAKISTAN involves the use of several mineral aggregates such as gravel, granites, sand and limestones. The use of limestones for concrete, however, is well patronized especially by private low cost housing builders due to its low cost compared to other alternatives. Limestones are known to have strength characteristics which are not uniform and as such vary from low to high depending on their petrographic state. This research provides some Engineering Geological characteristics of limestone types used for concrete works in parts of Sindh and offers a classification of limestones for easy field identification by Construction Engineers. The results of strength tests and petrologic examination confirm that there are different types of limestones with strengths that correlate positively with their level of geologic state. In addition, the most compacted limestone was found to be resistant to weathering and useful for producing concrete for construction work.
Keywords: Limestone types, aggregate strength,Geological Characteristics, concrete
1. Introduction
Concrete production for construction purposes is an activity which goes on in almost every country. Concrete is a mixture of fine and coarse aggregates, an appropriate binder and water in specified ratios and is used for constructing foundation walls, floor slabs, columns and many other elements of buildings. The strength of concrete depends on several factors including aggregate characteristics such as aggregate size, aggregate type and aggregate strength.
The size of aggregate used for concrete production is known to have some effect on the strength of the concrete. Shetty, (2000) has indicated that when large size coarse aggregates are used in concrete the strength of the concrete is reduced due to weak bonds caused by greater heterogeneity, internal bleeding and the development of micro cracks. In another research, Woode et al. (2015) confirmed that the coarse aggregate with the smallest comparative size gave the maximum compressive strength of concrete and that concrete strength reduces after a critical maximum aggregate size is attained. They further observed that as the heterogeneity of aggregates increases the compressive strength of concrete reduces.
In Jamshoro Sindh, several rock types for producing aggregates are available but the rocks which form the bulk of mineral aggregates used for construction include shale, limestone (Kesse, 1985; Woode, 1994; Adom-Asamoah et al, 2014). The type of construction aggregate used in a particular locality in Jamshoro depends on the requirements of the project involved and also proximity of the source of the aggregate to the project site. In the middle and northern sectors of the SINDH sandstone and limestone are extensively used..
Limestone and sandstone, which are converted to aggregates by crushing mechanically, are also exported for use in other regions of Sindh especially in the road sector. Due to the high cost of aggregates made from other igneous rocks, low cost housing construction works by indigenes are undertaken using limestone which is comparatively cheaper.
The limestone rock aggregates are usually produced by family groups who hand crush the limestone rock
from an outcrop using hammer and chisel. TheLimestone is crushed manually in some places by local villagers because they do not have the modern mechanical tools or machinery, some times crushing is of different sizes because of its strength, degree of weathering, compactness, hardness etc.
Field evidence has shown that different types of limestone occur in the Petaro Structural Unit. The different limestone types have not been clearly identified and categorized in terms of strength and geological features for concrete production. The lack of proper categorization of the limestone has resulted in a situation where producers of limestone rock aggregates mix up the various types before being offered for sale. The outcome of this mixing is that the strength of the resulting limestone rock aggregates is compromised and may be unpredictable.
The aim of this research, therefore, is to identify and classify the different types of limestone used in some parts of Sindh and to test for their strength properties so as to determine their suitability for use in construction activities.
2. Materials and Methods Materials
Different types of limestones were selected from rock outcrops of the Jamshoro
25.3349° N, 68.2143° E BHOLARI
25.3541° N, 68.2683° E KOTRI
25.5167° N, 68.3000° E PETARO
25.4169° N, 68.2743° E JAMSHORO
25.3850° N, 68.3649° E S U CAMPUS
The different limestone types are readily accessible to the communities along the formation.
Methods
Tests performed on the aggregates include aggregate impact value, aggregate abrasion value, 10% fines value, aggregate crushing value, water absorption test and petrologic examination of limestone samples.
. Aggregate Impact Value Test
The material used for the Aggregate Impact Value (AIV) is aggregate passing a 12.70 mm sieve and retained on a 9.52 mm sieve. The test samples were placed in the steel mould and compacted by a single tamping of 25 strokes of the tamping rod and subjected to 15 blows of the hammer dropping through a height of 381 mm (BS 812-112).
The crushed aggregate was sieved over a 2.36 mm sieve and the fraction passing 2.36 mm was weighed. The fraction retained on the sieve was also weighed and the aggregate impact value determined. Aggregate Abrasion Value Test
The test sample weighing 5000g was placed in the Aggregate Abrasion Value (AAV) testing machine and steel balls were added for the crushing as outlined in ASTM C131. The drum of the machine was rotated for 500 revolutions at a speed of 30 to 33 revolutions per minute and the crushed aggregate was discharged and sieved through a 1.70mm sieve and then weighed. The abrasion value of the coarse aggregates was then determined. Ten Percent Fine Value Test
Ten percent fines value is an indication of the resistance of aggregate to crushing when subjected to loading. The test which was carried out in line with BS 812-111, determined the forces required to produce 10% of fine values.
Aggregate Crushing Value Test
The Aggregate Crushing Value (ACV) is a measure of the resistance of an aggregate crushing under gradually applied compressive load. In this test the aggregate passing through 12.5mm and retained on sieve size 10mm is placed in 3 layers into the cylindrical mould, each layer is tamped with 25 strokes. The aggregate in the mould is then weighed, its surface leveled and the plunger inserted. The whole assembly is put into the compression testing machine, the load is started at an equal ratio, when the process is completed the sieving of sample is done in 2.36 mm sieve, the particles retained and passed is measured and ACV is then calculated.
. Water Absorption Test
Procedure for classification of limestones
Different types of limestones were identified in the Laki limestone Unit formation, which is the main source of limestone rock aggregates in Jamshoro area. The limestones were subjected to petrologic examination for various geologic characteristics such as structure, thickness, friability, fracture pattern, flakiness, lustre and colour. Petrographic analysis of some samples of the limestone rock..
3. Results
The results below are the outcome of the field inspections of rock outcrops within the Laki limestonel Unit and various strength tests conducted in the Laboratories in Jamshoro on the limestone samples.
Table 1. Showing strength tests results and water absorption of limestone types in Laki Limestone Jamshoro.
Sample AIV 10 % Fine Force/KN AAV ACV Force/ KN Water % % % Absorption % J1 36.37 18.29 110 29.85 32.17 400 1. J2 19.49 17.1 200 28.75 31.4 400 0. J3 15.30 13.14 260 27.45 17.75 400 0.
J1-
Calcareouslimestone ;
J2- Thin layered Fossiliferous limestone;
J3- Hard limestone
Table 2. A Geological Lithofacies of limestone types found in the Jamshoro area Sindh., Pakistan.
Limestone Type Description
Structure Fracture Thicknes s
Flakiness Lustre Colour
Hard compacted limestone with micro fossils
No Fractures
Variable Very hard, limestone, breakes with hammer gives sone echo sound when hit
Variable colours
J1 Different Calcareous varieties of
limestone Earthy brown, Dark yellow brown and cream.
Moderatel y
thick Fractures Thinly Flak y
Variable
layers between layered 10- Layers cannot Different J2 Individual grains and 200mm be broken with varieties of Thin layered of the source rock across th e
hand due Greasy brown,
limesto ne
in some layers are grains their thickness; dark
visible onl y
with Give s
moderate brown and
the ai d
o f
hand amount of dust cream.
lens .
Ma y
be when crushed
schistose. Massive Fractures Massive Give s
ver y
low Variable
Individual grains through layers > amount of dust Different J3 of the source rock grains 200mm when crushed Glassy varieties of
J
J
J
In view of its resistance to weathering J3 limestone may be valuable for highway construction and as a base material for buildings. The glassy luster of J3 limestone however, may cause weak bonding between the aggregate and cement mortar due to its smooth surface. The J3 limestone rock aggregate have angular shapes and could form good interlocking network which makes it superior aggregate over rounded aggregates in terms of strength. Zaidi, S.M., et al., 2008
Three different varieties of laki limestone Jamshoro area Sindh, Pakistan.
Conclusion
Three different types of limestone have been identified as the source of construction aggregates for concrete production in parts of Jamshoro area. They include quartzitic sandstones, thin layered limestone and metalimestone and have been classified as J1, J2 and J3 limestone types. The limestone types have presented different strength values which correspond to their degrees of strenghth. The J3 limestone has the highest strength and and may be most useful for concrete suitable for structural work. The J1 limestone is the least weathered as indicated by the presence of some sedimentary features.
References
- Ahmed, S., Hussain, S., Qamar-uddin, A.G. and Ali, M., 2015. STUDY ON GENERAL GEOLOGY, FOSSILS AND CUT STONE OF THANO BULA KHAN, JAMSHORO, SINDH, PAKISTAN. Gomal University Journal of Research , 31 (2).
- Arshad, H. and Qiu, Y.J., 2012. Evaluation of Dina Aggregates for Pavement Construction in Pakistan. In Advanced Materials Research (Vol. 548, pp. 239-242). Trans Tech Publications. .
- Ghaffar, A., Siddiqi, Z.A. and Ahmed, K., 2016. Assessing suitability of Margalla crush for ultra high strength concrete. Pakistan Journal of Engineering and Applied Sciences.
- (^) 4. Gondal, M.M.I., AHSAN, N. and JAVID, A.Z., 2009. Engineering properties of potential aggregate resources from eastern and central Salt Range, Pakistan. Geol. Bull. Punjab Univ , 44.
- (^) 5. Gondal, M.M.I., Ahsan, N.A.V.E.E.D. and Javaid, A.Z., 2008. Evaluation of Shaki Sarwar and Rajanpur aggregates for construction in southern Punjab Province, Pakistan. Geol. Bull. Punjab Univ , 43 , pp.101-107.
- (^) 6. Gondal, M.M.I., Ahsan, N.A.V.E.E.D. and Javaid, A.Z., 2008. Evaluation of Shaki Sarwar and Rajanpur aggregates for construction in southern Punjab Province, Pakistan. Geol. Bull. Punjab Univ , 43 , pp.101-107.
- (^) 7. Qureshi, M.A., Aslam, M., Shah, S.N.R. and Otho, S.H., 2015. Influence of Aggregate Characteristics on the Compressive Strength of Normal Weight Concrete. University of Engineering and Technology Taxila. Technical Journal , 20 (3), p.1.
.
- Yaqub, M. and Bukhari, I., 2006, August. Effect of size of coarse aggregate on compressive strength of high strength concrete. In 31st Conference on Our World In Concrete & Structures (pp. 16-17).
- Zaidi, S.M., Rafeeqi, S.F.A., Ali, M.S. and Khan, A.M., 2008. Aggregate characterization-an important step towards addressing construction issues in Pakistan. In First international conference on construction in developing countries (ICCIDC–I) “Advancing and integrating construction education, research & Practice” August (pp. 4-5).
