Yüksel TAŞDEMİR, Emine AĞAR

Bitümlü kaplamalarda düşük sıcaklık çatlaklarının incelenmesi

Düşük sıcaklık çatlaklarını etkileyen faktörler konusunda; bitümlü bağlayıcı oranını, katkı türlerini, hava boşluğu oranını ve yaşlandırma sürelerini değiştirerek gerçekleştirilen kapsamlı bir çalışma bugüne kadar yapılmamıştır. Bu çalışmada, düşük sıcaklık çatlakları üzerinde, belirtilen faktörlerin etkilerini ayrıntılı olarak inceleyebilmek amacıyla, deneysel çalışma gerçekleştirilmiştir. Bitümlü karışımların, düşük sıcaklık çatlaklarına direncini ölçmek için sınırlandırılmış numunede termal gerilme testi cihazı kullanılmıştır. Deney sonuçları üzerinde, İstatistiksel Analiz Sistemi paket programı yardımıyla, genel lineer model işlemleri kullanılarak kovaryans analizi yapılmıştır. Bitümlü bağlayıcı oranı ve hava boşluğu oranının, karışımın kırılma sıcaklığı üzerinde etkili olmadığı belirlenmiştir. Katkı türüne göre, kırılma sıcaklığının değiştiği, yaşlanma süresi arttıkça, kırılma sıcaklığının yükseldiği görülmüştür.

Investigation of low temperature cracking on asphalt pavements

Researches have been carried out for more than half century on low temperature cracking which hasn’t solved yet. Low temperature cracking arises due to extreme cold temperature. The aim of this study is to investigate the importance of low temperature cracking AC pavements. No comprehensive study has been investigated the influence of asphalt content, modifier type, air voids content and aging levels on low temperature cracking of asphalt concrete (AC) mixtures in single experimental research program. In this research, laboratory tests were carried out to evaluate the effect of all factors mentioned above on the low temperature cracking properties of AC mixtures. The thermal stress restrained specimen test (TSRST) was used to investigate the low temperature cracking resistance of the AC mixtures. The analysis of covariance was performed using a general linear model (GLM) procedure in the Statistical Analysis System (SAS) package program. The procedure was incorporated on test results to develop models for determining fracture temperature and fracture strength. It was found that developed models were significant at 95% significance level and asphalt content and air voids content were not significant factors on low temperature cracking. It was observed that fracture temperature changed according to used modifier type and became warmer with the increase of degree of aging.

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