In this study the effect of different amounts of lime and natural pozzolan on geotechnical properties of a silty sand soil has been investigated. To do this, 20 treatments were prepared with adding five lime levels of 0, 1, 3, 5 and 7% (by weight) and four levels of pozzolan including; 0, 5, 10 and 15%. Compaction characteristics, compressive strength and bearing capacity of the treatments were determined using standard test procedures. For evaluation of compressive strength, cylindrical specimens (3.5 cm in diameter and 7 cm in length) were made and cured for three different ages including 7, 14 and 28 days in three replication. Result of compaction tests showed that adding of both lime and pozzolan alone and with together increase optimum moisture content and decrease the maximum dry density of treated soil samples. Statistical analysis using SPSS software showed that although adding of natural pozzolan and lime to the soil increases the compressive strength significantly, but adding of them with together is more effective. So that the compressive strength of a treatment having 3% lime and 15% pozzolan was found to be 16 times of untreated sample. Furthermore, the results of California Bearing Ratio, CBR test showed that the values of CBR in different treatment increased up to 12 times of untreated sample.

中文翻译：

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用天然火山灰和石灰改善粉质砂土的岩土性能

在这项研究中，研究了不同量的石灰和天然火山灰对粉质砂土岩土特性的影响。为此，准备了20种处理方法，添加了5种石灰水平，分别为0、1、3、5和7％（按重量计）和4种火山灰含量，包括：0、5、10和15％。使用标准测试程序确定处理的压实特性，抗压强度和承载力。为了评估抗压强度，制作圆柱形样品（直径3.5厘米，长度7厘米），并固化三个不同的年龄，包括7天，14天和28天，一式三份。压实测试的结果表明，单独添加石灰和火山灰以及同时添加石灰和火山灰会增加最佳水分含量，并降低处理过的土壤样品的最大干密度。使用SPSS软件进行的统计分析表明，虽然向土壤中​​添加天然火山灰和石灰可以显着提高抗压强度，但将它们一起添加更为有效。因此，发现具有3％的石灰和15％的火山灰的处理的抗压强度是未处理样品的16倍。此外，California轴承比率CBR测试的结果表明，不同处理下的CBR值增加到未处理样品的12倍。