Kajian ini telah dijalankan untuk menyiasat kelakuan pasir penyambung turapan blok konkrit saling mengunci pada jarak sambungan dan kecerunan yang berbeza. Model di makmal yang berukuran 1.2×0.6 (m2) telah dibina dan blok konkrit daripada jenis quadpave yang bersaiz 200×100×60 (mm3) telah digunakan sebagai lapisan atas. Jarak sambungan yang digunakan adalah 2, 4 dan 6 mm dengan kecerunannya adalah 0, 5, 10 dan 15%. Uji kaji tarik keluar dijalankan untuk setiap keadaan. Hasil kajian menunjukkan jarak sambungan 2 mm adalah jarak sambungan yang paling sesuai untuk gunakan pada jalan yang bercerun. Semakin besar jarak sambungan, semakin menurun sifat penguncian antara blok konkrit. Ini berlaku di mana daya yang diperlukan untuk menarik blok keluar semakin mengecil apabila jarak sambungan semakin lebar. Kehadiran air dalam kuantiti yang sedikit menyebabkan pasir pengisi menjadi lebih mampat tetapi apabila air terlalu banyak, hakisan akan berlaku. Kajian ini mencadangkan kecerunan maksimum penggunaan turapan blok konkrit saling mengunci adalah sehingga 10% untuk mengelakkan hakisan pasir pada penyambung dan juga penurunan sifat penguncian antara blok konkrit.
In order to cope with the ever-increasing traffic loading and to minimise the cost of road construction and maintenance, several road trials of High Modulus Base (HMB) materials containing a 15 penetration bitumen (known as HMB15) have been carried out in the UK since 1990s. It has been showed that, although HMB15 behaved in a similar way to conventional Dense Bitumen Macadam with a cost saving of approximately 25%, its long-term durability (aging and moisture damage) is still a major concern of researchers as considerable deteriorations have been commonly observed during the ongoing investigations on cored samples from the sites (either with or without traffic loading). The aim of this paper was to quantitatively show the relationship between aging properties of HMB15 and its binder film thickness (binder content), so that an optimum binder content could be determined. In order to achieve this, 5 groups of cylindrical HMB15 specimens with different binder contents (3.5%, 4%, 4.5%, 5% and 5.5%) were fabricated and subjected to SHRP long-term oven aging test (at 85oC for 5 days), their mechanical properties both before and after aging simulation were tested using Indirect Tensile Stiffness Modulus (ITSM) tests. In addition, binders were recovered at different aging stages and their rheological characteristics were investigated with Dynamic Shear Rheometer (DSR) tests. Based on these, aging indices of different groups were calculated and their mathematical relationship with binder film thicknesses was regressed. The results show that the aging properties of HMB15 mixtures are significantly affected by their binder film thicknesses. However, regression analysis between aging indices and binder film thicknesses indicates that, as the binder film becomes thicker than 9.5 μm, the change of aging indices with film thicknesses becomes minor and therefore, a film thickness of approximately 9.5 μm was recommended for HMB15 mixtures.
The dynamic shear rheometer (DSR) is one of the most complex and powerful instruments currently used to characterise the linear viscoelastic (LVE) rheological properties of bituminous binders. However, the DSR also has its limitations in that the measured complex modulus data are exposed to errors, known as compliance (testing) errors, particularly at low temperatures and/or high frequencies. This study was conducted to investigate the validity of equations developed by Schröter and associates on complex modulus data collected using the DSR. The equations used were originally developed based on the calibration of the advanced rheometric expanse system (ARES) rheometer. It was found that those equations are able to satisfactorily correct the data on unmodified bitumens and unaged bitumen-filler mastics, including unaged and aged samples. Similar results were also observed for storage and loss moduli master curves. Finally, the 2S2P1D Model was used to calibrate the corrected complex moduli data and it was found that the model satisfactorily simulates the rheological properties of tested samples.