Investigation of resilient modulus of medium-dense sand-clay mixtures with different clay contents under repeated traffic loads

Abstract

Resilient modulus is commonly used in prediction of long-term deformation performances of pavement foundation layers under repeated traffic loads. For this reason, the determination of this material property accurately has a great importance in pavement designs. In this study, resilient modulus of medium-dense sand-clay mixtures was investigated through cyclic triaxial and heart-shaped stress paths. For this purpose, sand-clay specimens having a clay content as 0%, 5%, 10%, and 20% by weight were prepared at an initial relative density of 50% and tested using hollow cylinder testing apparatus. According to the test results, the resilient modulus values of sand-clay mixtures are overestimated by cyclic triaxial stress path, which results in the underestimation of deformation behavior of medium-dense sand-clay mixtures under traffic loads compared to heart-shaped stress path. Based on the findings of this study, it is concluded that a heart-shaped stress path should be taken into consideration for a more accurate prediction of resilient modulus of sand-clay mixtures for pavement designs.

Keywords

• Resilient modulus
• Sand-clay mixture
• Heart-shaped stress path
• Cyclic triaxial stress path

Tekrarlı trafik yükleri altında farklı kil içeriklerine sahip orta-sıkı kum-kil karışımlarının esneklik modülünün incelenmesi

Öz

Esneklik modülü, tekrarlı trafik yükleri altında yol temel tabakalarının uzun dönem deformasyon performansının tahmin edilmesinde yaygın olarak kullanılmaktadır. Bu nedenle, bu malzeme özelliğinin doğru tayini yol tasarımlarında büyük öneme sahiptir. Bu çalışmada, orta sıkı kum-kil karışımlarının esneklik modülü, dinamik üç eksenli ve kalp şekli gerilme izleri ile araştırılmıştır. Bu amaç doğrultusunda, ağırlıkça %0, %5, %10 ve %20 kil içeren kum-kil numuneleri %50 başlangıç rölatif sıkılıkta hazırlanmış ve yarık silindir deney cihazı kullanılarak test edilmiştir. Deney sonuçlarına göre kum-kil karışımlarının esneklik modülü değerleri dinamik üç eksenli gerilme izi ile daha fazla tahmin edilmektedir. Bu durum ise orta-sıkı kum-kil karışımlarının trafik yükleri altındaki deformasyon davranışının kalp şekli gerilme izine kıyasla daha düşük tahmin edilmesine sebep olmaktadır. Bu çalışmanın bulgularına dayanarak, kum-kil karışımlarının esneklik modülünün yol tasarımları için daha doğru bir şekilde tahmin edilmesinde kalp şekli gerilme izinin göz önüne alınması gerektiği sonucuna varılmıştır.

Anahtar Kelimeler

• Esneklik modülü
• Kum-kil karışımı
• Kalp şekli gerilme izi
• Dinamik üç eksenli gerilme izi

Kaynakça

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