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80Scaled Aggregate Piers – AASHTO No. 57As the process of 1/10 th scale pier testing was being developed, the use of full-scale sizeaggregate was deemed to be inappropriate for aggregate pier construction. While aggregatepier elements are typically built using well graded aggregate, recycled concrete and oftenAASHTO No. 57 crushed limestone aggregate (Fox and Cowell, 1998), the gradation of thefull-scale material had to be altered by the order of 10 for the method of scaling to be valid.Due to local availability and being relatively inexpensive, AASHTO No. 57 aggregate wasfirst selected and utilized for the purpose of 1/10 th scale aggregate pier construction.Knowing the particle size distribution curve for the full size AASHTO No. 57 aggregate, theprototype aggregate mix was developed as outlined in Table 20 and Figure 46 as outlinedabove (Wisconsin DOT, 2003).Table 20: Full-scale and 1/10 th scale aggregate pier dimensionsFull-scale sizeaggregate Pier*1/10 th scale sizeaggregate pierTotal height, m 3.70 0.370Diameter, m 0.76 0.08Volume, m 3 1.7 0.0017Initial void ratio 0.33 0.34Initial ρ dry , kg/m 3 2,100 2,015Loose lift thickness, m 0.914 0.09Compacted lift thickness, m 0.305 0.03Total mass of aggregate/pier, kg 3,523 3.4Total number of lifts 12 12Total mass of aggregate/lift, kg 294 0.282* Values obtained from Pham and White, 2007**Values for prototype aggregate piers are not exactly 1/10 th scale due to a difference indensityWhile having a typical full-scale compacted aggregate pier to be 0.305 m thick, 0.76 m indiameter and have compacted aggregate density of 2,100 kg/m 3 (White et.al., 2007), theamount of aggregate to be used for each scaled lift was estimated at 280 g by weight.