Search Results (2)

This study reviewed new concept waterproofing performance gradation to respond to the limit of unified single standard performance standard used in each country from the past until now. This study was carried out using the standard test data from 34 products tested and evaluated by Korea’s national quality test institution for 2 years (2018~2019) based on national standard specification (KS F 4934, Self-Adhesive Rubberized Asphalt Sheet). Major proposal contents utilized the result values of 9 waterproofing performance evaluation criteria included in the national standard specification. Major study contents and results are as follows. Existing widely used domestic and overseas standard grading (Stanine, Sten Scores, Grade 5 Scale, energy consumption efficiency, and other grading) theories were investigated and analyzed. Based on the analysis contents, standard Grade 5 Scale system suitable for waterproofing material performance grading was selected and applied. Grade sections were set according to the application ratio for each grade section of Grade 5 Scale (grade 1 with 10%, grade 2 with 20%, grade 3 with 40%, grade 4 with 20% and grade 5 with 10%). According to the set sections, performance grades were derived for 9 test criteria of 34 products. Section setting standard for grade section was derived centered on the performance result values of 9 criteria. As a result, average value of waterproofing performance of each of 9 test criteria for 34 products was verified to have 1.2 times to 7.52 times higher performance value than the minimum quality standard (based on grade 5). Such results sufficiently showed the limit of the current unified single standard performance application. Also, as a solution for waterproofing quality degradation problem, possibility to apply the waterproofing performance grading of this study was verified. Therefore, through this study, it is decided that new concept quality standard to pursue future waterproofing industry development can be set, quality reinforcement is possible by performance grading for each product and sustainable waterproofing performance maintaining effect at the waterproofing construction site can be expected with the use of such gradation. Full article

It is well known that the performance of hot mix asphalt (HMA) in service life is closely related to a proper aggregate gradation. A laboratory study was conducted to investigate the effects of nominal maximum aggregate size (NMAS) on the performance of stone matrix asphalt (SMA). The volumetric characteristics and performance properties obtained from wheel tracking tests, permeability test, beam bending test, contabro test are compared for SMA mixes with different NMAS. The results indicated that voids in mineral aggregate (VMA) and voids filled with asphalt (VFA) of SMA mixtures increased with a decrease of aggregate size in aggregate gradation. SMA30 had the lowest optimum asphalt content among all the mixtures. Increase of NMAS contributed to improvement of the rutting resistance of SMA mixtures. However, a decrease of NMAS showed better cracking and raveling resistance. Permeability rate of SMA was primarily affected by the air voids (AV) and break point sieve, but was also sensitive to aggregate gradation to some extent, with reduced NMAS corresponding to less permeability rate. Based on the test results, SMA5 and SMA13 are suggested to be used as a water-proof layer in bridge deck pavement, and SMA20 and SMA30 are suggested to be used as binder course in asphalt pavement, which needs to possess superior rutting resistance at high temperature. Full article