Effects of aging, temperature, moist aggregates and filler type on performance of warm mix asphalt incorporating rh-wma additive / Bashir M. Bashir Aburawi
Campuran asphalt panas (HMA) telah menjadi bahan utama yang digunakan
di dalam turapan sejak beberapa dekad yang lalu. Sejak kebelakangan ini, berbanding
campuran HMA konvensional, campuran asfalt suam (WMA) telah menunjukkan
potensi yang besar dan ber manfaat tidak dapat diperolehi daripada campuran HMA,
kerana campuran WMA boleh dihasilkan pada suhu yang lebih rendah tanpa memberi
kesan kepada prestasi turapan. Bahan tambah WMA boleh mengurangkan kelikatan
pengikat. Oleh itu, suhu pengeluaran dan pemadatan adalah lebih rendah berbanding
campuran HMA konvensional. Salah satu bahan tambah yang digunakan untuk
menghasilkan WMA adalah sejenis lilin yang dinamakan sebagai RH-WMA. Di dalam
tesis ini, ciri-ciri reologi asfalt PG64 dengan dan tanpa RH-WMA pada keadaan
penuaan yang berbeza telah dikaji. Secara keseluruhan, keputusan ujian reologi
pengikat menunjukkan bahawa kandungan RH-WMA telah memberi kesan yang
signifikan terhadap parameter reologi asfalt pengikat dari segi kelikatan, G*/sin δ dan
G*sin δ. Teknik analisis imej telah digunakan untuk mengelaskan kegagalan perekatan
dengan menggunakan ujian hentaman. Ujian hentaman telah dijalankan terhadap
acuan baru yang telah direka khas dan kesan keadaan penuaan dan suhu ujian asfalt
pengikat dengan RH-WMA telah dikaji. Analisis keputusan menunjukkan bahawa
penuaan jangka masa pendek dan panjang asphalt pengikat telah meningkatkan
kegagalan rekatan. Suhu pembinaan (campuran dan pemadatan) telah dikurangkan
dengan penambahan bahan tambah RH-WMA yang menyebabkan penurunan kadar
kelikatan. Walau bagaimanapun, pengurangan suhu campuran boleh menghalang
kelembapan daripada tersejat sepenuhnya daripada agregat dan telah memberi kesan
kepada ikatan asfalt dan menjadikan campuran terdedah kepada pelucutan. Dua bahan
tambah anti pelucutan iaitu kapur terhidrat dan pengubahsuai turapan (PMD) telah
digunakan untuk mengurangkan kesan pemusnah disebabkan oleh kelembapan. Kesan
kandungan RH-WMA, suhu penghasilan dan ujikaji terhadap prestasi campuran telah
dikaji dari sudut kekuatan tegangan tidak terus (ITS), modulus kebingkasan (MR) dan
kekukuhan rayapan. Hasil ujian mendapati bahawa nilai ITS dan MR berkurang dengan
peningkatan kandungan RH-WMA pada suhu ujian dan campuran masing-masing.
Kesan pengeringan agregat yang tidak sempurna terhadap sifat-sifat mekanik
campuran berasfalt telah dibuktikan dengan jelas dalam tesis ini. Oleh itu, penggunaan
agregat yang kering sepenuhnya adalah penting untuk memastikan prestasi campuran
yang memuaskan. Hasil ujian juga menunjukkan bahawa penuaan telah meningkatkan
rintangan terhadap kelembapan bagi WMA. __________________________________________________________________________________
Conventional Hot Mix Asphalt (HMA) has been the primary material used in
pavement in past decades. Recently, compared to conventional HMA, Warm Mix
Asphalt (WMA) has shown great potential and offers benefits not given by HMA,
since the WMA can be produced at lower temperatures without affecting pavement
performance. Since WMA additives can reduce the binder viscosity, the production
and compaction temperatures can be lowered, compared to conventional HMA. One
of the additives used to produce WMA is a type of wax named RH-WMA. In this
thesis, the rheological properties of a conventional a virgin PG64 asphalt binder with
and without RH-WMA at different aging conditions were investigated. The overall
rheological binder tests results indicated that RH-WMA content had significant effects
on the rheological parameters of asphalt binders in terms of viscosity, G*/sin δ and
G*sin δ. Image analysis technique was used to classify the adhesive failure by using
impact test. The impact test was conducted on a newly fabricated mould and the effects
of aging conditions and test temperatures of asphalt binder incorporating RH-WMA
were investigated. The analysis results showed that short-term aging and long-term
aging of asphalt binder increased the percentage of adhesion failure. The construction
temperature (mixing and compaction) was reduced by the addition of RH-WMA
additive due to viscosity reduction. However, the reduction of mixing temperatures
may prevent moisture from being completely evaporated from the aggregate and thus,
effect the asphalt binder bond, making the mixture more susceptible to stripping. Two
anti-stripping additives, namely hydrated lime and Pavement Modifier (PMD) were
used to reduce the destructive effects of moisture. Effects of RH-WMA content,
production and testing temperatures on mixture performance were investigated in
terms of indirect tensile strength, resilient modulus and creep stiffness. The result
indicates that both ITS and MR decreased as the RH-WMA content increased at the
respective test and mixing temperatures. The effects of incomplete drying of
aggregates on the mechanical properties of asphalt mixtures were clearly evident in
this thesis. Therefore, the use of fully dried aggregates was important in ensuring
satisfactory mix performance. Mixes prepared with 3% RH-WMA and compacted at
125°C° exhibit the best performance compare with HMA. Specimen incorporating
PMD filler improved resistance to stripping compared to mixes with hydrated lime
filler regardless of compaction temperature. The test results also indicated that aging
improved the moisture resistance of WMA.
Effects of aging, temperature, moist aggregates and filler type on performance of warm mix asphalt incorporating rh-wma additive / Bashir M. Bashir Aburawi
Effects of aging, temperature, moist aggregates and filler type on performance of warm mix asphalt incorporating rh-wma additive_Bashir M. Bashir Aburawi_A9_2017_MYMY