QUALITATIVE EVALUATION OF FINE AGGREGATE FOR SELECTED QUARRIES IN AL-NAJAF AL-ASHRAF

Abstract

Fine aggregate considered as the oldest building material known by human; it's not inert substance. Each of its physical and chemical properties need theoretical and laboratory studies because of its effect on the compressive strength and durability of concrete. One of the most important properties is the content of sulphate salts, which must be taken into account in all construction works. This research aims to conduct laboratory qualitative assessment of fine aggregate to demonstrate its suitability for construction work and quality assurance. Samples of fine aggregate (sand) were collected from four quarries in Al-Najaf Alashraf [(Syd Ali (S1), Wilaya Ali (S2), Syd Ahmed (S3), and Muhand Al-Khiat (S4)]. Some of the physical tests (sieve analysis, deleterious materials (clay%), bulk density, specific gravity, and absorption), chemical analysis for sulphate salts content, X-Ray technology for mineral composition as well as the compressive strength test were conducted on these samples. Sieve analysis was compared with the Iraqi specifications (IQS), British Standard (B.S), and American Society for Testing and Materials (ASTM). Under the standard Iraqi specifications, the results showed that three of the samples [Wilaya Ali (S2), Syd Ahmed (S3), and Muhand Al-Khiat (S4)] fall within Grading Zone (III) which are used in concrete works. While the sample Syd Ali (S1) falls within Grading Zone (IV) which is used in other construction works, such as Tiles and Rendering. On the other and, as per the British Standard, all samples are 188 Huda Z. Kubba et al. compatible for Grading Zone Limits, for the ASTM, all samples are not compatible for the Grading Zone Limits. The sulphate salts content (SO3) of sample Syd Ali (S1) and Wilaya Ali (S2) is (0.28, 0.11%), respectively, falls within the limits of the standard Iraqi specification, while sulphate content of samples Syd Ahmed (S3) and Muhand Al-Khiat (S4) is (10.65, 2.2%), respectively. The compressive strength of concrete of the sample Wilaya Ali (S2) is (24, 33) MPa for age (7, 28) days, respectively, and it is higher than the other Samples Syd Ahmed (S3) and Muhand Al-Khiat (S4) by (0.54, 0.39) % MPa and (0.42, 0.24) MPa, respectively for age (7, 28) days, while the compressive strength of the sample Syd Ali (S1) is slightly lesser than the Sample (S2) by (0.22, 0.06) % MPa for age (7, 28) day. From X-Ray diffraction test, it appears that there are three minerals (Calcite, Quartz, and Gypsum) for Samples [(Syd Ali (S1), Wilaya Ali (S2), Syd Ahmed (S3), and Muhand Al-Khiat (S4)], except for sample Wilaya Ali (S2) where Gypsum is not found, and it's of trace amount for sample Syd Ali (S1) which is (1.0%), large amount for sample Syd Ahmed (S3) which is (5.1%), and very large amount for sample Muhand Al-Khiat (S4) which is (47.5%). The results of X-Ray diffraction test confirm the results of chemical analysis for sulphate salt content (SO3) in all samples especially for Wilaya Ali (S2). From the results of this research, its clear that Sample Wilaya Ali (S2) is the best for concrete works where the grading and sulphate salts content (SO3) is accepted by (IQS), and this sample gives an accepted compressive strength. While Sample Syd Ali (S1) was the finest with an accepted sulphate salts content as compared with (IQS) which makes it is suitable for other construction works rather than concrete. Samples, Syd Ahmed (S3) and Muhand Al-Khiat (S4) are with high sulphate salts content (which cannot be treated) as compared with (IQS) which make them not compatible for concrete and other construction works.

Keywords

• Fine aggregate
• Quarries; Grading
• Sulphate salts
• Compressive strength