The sand of zone II is proper for the preparation of concrete if the sand of zone I is selected, the sand ratio should be improved and the amount of cement should be enough to satisfy the workability of concrete if the sand of zone III is used, the sand ratio should be lowered properly to guarantee the strength of concrete. Taken the cumulative screen residue percentage and the size of sieve holes respectively as the ordinate and the abscissa, the numbers regulated in Table 5.5 can be drown into sieve-analysis curves of the upper and the lower limits of three grading regions, shown in Figure 5.2. Compared with the standard indexes in Table 5.5, the real gradations of sand particles are allowed to exceed the limits slightly (except 4.75 mm and 0.60 sieves), but the total percentage should not be more than 5%. The cumulative screen residue in each group represents a gradation.Īccording to GB/T 14684-2001, there are three grading regions of sand when it is calculated by the percentage of the cumulative screen residue of 0.60 mm square-hole sieve, shown in Table 5.5. The relationship between the cumulative screen residue and the unit screen residue is shown is Table 5.4. Screen 500 g dry sand obtained by sample splitting device from coarseness to fineness, then weigh their screen residue, and calculate their percentage a 1, a 2, a 3, a 4, a 5, a 6 (which means the mass of screen residue to the mass of the total sample sand) and the percentage of cumulative screen residue A 1, A 2, A 3, A 4, A 5, A 6 (which refers to the screen residue of one sieve to the sum of all the unit screen residue percentages whose sieves are thicker than it).
A set of square-hole sieves whose diameters are 4.75 mm, 2.36 mm, 1.18 mm, 0.60 m, 0.30 mm and 0.150 mm are adopted specifically. Grading region and fineness modulus can be used to express the gradation and the coarseness of sand particles respectively. The grain gradation and coarseness of sand are determined by screen residue analysis. In Building Materials in Civil Engineering, 2011 (1) Grain Gradation and Coarseness of Sand (1997), Sudarvizhi and Ilangovan 2012, Suresh et al. (2015), Sakthieswaran and Ganesan (2014), Shoya et al. (2004), Hwang and Laiw (1989), Jaivignesh and Gandhimathi (2015), Khan et al. (2010a,b)Īyano and Sakata (2000), Gowda and Balakrishna (2014), Hosokawa et al. (2014), and Sathya and Shanmugavalli (2014)īoakye et al. (2012b), Rajaselvi and Beatrice (2015), Karthick et al.
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