DAC20603

SOALAN CONTOH

TURAPAN/PAVEMENT

Q1. Describe the differences between Telford’s and Macadam’s pavement structure design concept.Q1. Terangkan perbezaan konsep reka bentuk di antara Telford dan struktur turapan Macadam .

Telford's pavement section was about 350 to 450 mm (14 to 18 inches) in depth and generally specified three layers. The bottom layer was comprised of large stones 100 mm (4 inches) wide and 75 to 180 mm (3 to 7 inches) in depth (Collins and Hart, 1936). It is this specific layer which makes the Telford design unique (Baker, 1903). On top of this were placed two layers of stones of 65 mm (2.5 inches) maximum size (about 150 to 250 mm (6 to 9 inches) total thickness) followed by a wearing course of gravel about 40 mm (1.6 inches) thick (see Figure). It was estimated that this system would support a load corresponding to about 88 N/mm (500 lb per in. of width).

Macadam pavement structure

He used a sloped subgrade surface to improve drainage (unlike Telford who used a flat subgrade surface) on which he placed angular aggregate (hand-broken with a maximum size of 75 mm (3 inches)) in two layers for a total depth of about 200 mm (8 inches) (Gillette, 1906). On top of this, the wearing course was placed (about 50 mm thick with a maximum aggregate size of 25 mm) (Collins and Hart, 1936). Macadam's reason

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for the 25 mm (1 inch) maximum aggregate size was to provide a "smooth" ride for wagon wheels.

The total depth of a typical MacAdam pavement was about 250 mm (10 inches) (refer to Figure 1.5).  MacAdam was quoted as saying "no stone larger than will enter a man's mouth should go into a road" (Gillette, 1906).  The largest permissible load for this type of design has been estimated to be 158 N/mm (900 lb per in. width). 

Q2 How is Asphalt Cutback produced?

Q2 Bagaimana Asphalt cutback dihasilkan?SolutionAsphalt dissolved in solvent (lower molecular-weight hydrocarbons such as diesel oil, kerosene or gasoline) • When solvent evaporates – leaves asphalt residue as a binder (fast-curing cutback produced with gasoline, medium-curing with kerosene, and slow-curing with diesel oil.

Q3 What are its advantages and disadvantages of cutback bitumen?S3 Apakah kebaikan dan keburukan bitumen bitumen cutback ?SolutionFaster curing = higher cost• Disadvantages:

1. • Solvents more expensive2. • Hazardous due to volatility of solvents3. • Release environmentally-unacceptable hydrocarbons into the atmosphere

Q4 Define Asphalt Emulsions S4 Berikan definasi asfal emulsiSolution

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• Asphalt dispersed in water (60 – 70% asphalt & 30 – 40% water + small quantity of emulsifying agent (~ soap material)• Use of emulsions is increasing

Q5 What are its advantages and disadvantages Asphalt Emulsions?S5 Nyatakan kelebihan dan kelemahan asfal emulsi .Solution

Advantages• Can be applied in damp weather• Aggregates can be hot or cold• Eliminates need for fuel to heat & dry aggregates for HMA• Reduces energy requirements through the reduction or elimination of petroleum distillates used in cutback asphalts

Disadvantages• Because asphalt is suspended in water – it is susceptible to being washed off a surface by rainwater if it is not sufficiently cured• Unbroken emulsions may be carried into streams causing ground contamination

S3 (a) Pemilihan bitumen yang mempunyai ciri sesuai sebagai bahan campuran konkrit asfal mempastikan turapan lentur berkualiti tinggi. Senaraikan empat(4) ciri bitumen gred penetrasi yang sesuai tersebut.

1. Bahan penyimen yang kuat, mudah merekat serta tahan lasak.2. Mempunyai sifat kalis air yang tinggi.3. Bahan plastik yang mempunyai sifat kebolehlenturan yang terkawal apabila

bercampur dengan agregat.4. Bersifat koloid.

(4 markah)

(b) Terangkan empat (4) objektif rekabentuk campuran konkrit asfal.

Mixtures of aggregate and asphalt cement binderabout 95% aggregate by weightabout 75% aggregate by volumeideally, 3-5% air voids

1. Flexibility

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high binder contentlow viscosity binder

2. Long-term Durability fluid properties of binder dry clean aggregates water causes “stripping” strong porous angular stone durable aggregates (LA abrasion)

3. Workability: Ease in which material is handled and laid and compacted. poor compaction leads to deformation and the permeability of water and

air. temperature affects workability

4. Strength high viscosity binder crushed stone aggregates (interlock)

(4 markah)

(c) Bitumen cutback and bitumen emulsi mempunyai ciri berbeza.

(i) Terangkan tiga (3) perbezaan berkenaan dengan jelas.(6 markah)

Emulsified asphaltEmulsions When mixed with water binders will generally settle out. An emulsifier must be added to give a stable solution. Bitumen paints are made this way. The water evaporates and the bitumen remains on the surface. The current types of cold rolled materials are based on emulsions.

Emulsified asphalt (emulsion) is a mixture of asphalt cement, water and emulsified agent. This emulsified asphalt is usually used for prime coat (binder and road-base) and tack coat (binder and wearing).

Because the asphalt cement will not dissolve in water, asphalt cement and water exist in separate phases as in figure shown.

Cutback asphaltsCutbacks This term is used to describe a mixture of a binder and a light volatile oil. They are liquid at low temperatures until the volatile oil evaporates.. Due to the release of solvents into the atmosphere they are now rarely used.

Cutback asphalts are liquid asphalts which are manufactured by adding (cutting back) petroleum solvents to asphalt cements.

They are made to reduce the asphalt viscosity for lower application temperature. Application to aggregate or pavement causes the solvent to escape by evaporation and leave the asphalt cement residue on the surface.

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Based on the rate of evaporation, cutback asphalt are divided to three types – rapid curing (RC), medium curing (MC) and slow curing (SC).

(ii) Bincangkan tiga (3) sebab penggunaan bitumen emulsi lebih meluas digunakan.

(6 markah)

Primary objective is to use for road surfacing without much heating.

It is stable under transportation ,storage &application condition.But it may break soon after application.It may have low viscosityIt may flow due to irregular spraying but not due to road irregularitiesImportant properties of Bitumen emulsion:

1. Stability2. Viscosity3. Breaking4. Adhesivity

As main advantages this improves the handling of bitumen at room temperature.Promotes surface interactions .Its mixture with the aggregate attains full strength.Economical and saves energy .Reduced atmosphere pollution. Water can also added before use to dilute as per requirement.

Rains can not effect it at the time of use and after use.

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AGREGAT

S1 (a) Pembinaan subgred jalanraya memerlukan tanah yang mempunyai ciri-ciri sesuai digunakan. (i) Senaraikan empat (4) ciri tanah yang sesuai dijadikan subgred.

The good sub-grade are;1. Stable under the varieties of vehicle load and climatic condition.2. The strength remain along the design period3. Able to drain water.

4. stabil di bawah pelbagai beban kenderaan dan cuaca.5. mempunyai kekuatan yang berkekalan sepanjang hayat rekabentuk. 6. sebaik-baiknya dapat mengalirkan air.7. Prevents soil settlement and frost damage

Provides stabilityReduces water seepage, swelling and contractionReduces settling of soil

(ii) Untuk setiap ciri yang dinyatakan, terangkan ujian bagi mengenalpasti ciri tersebut

.Ujian-ujian yang perlu dijalankan:

Kehilangan akibat nyalaan Had Cecair dan Had Plastik Pemadatan Nisbah Galas California

(8 markah)

(b) Kekuatan subgred sebagai struktur turapan lentur bergantung kepada beberapa faktor kejuruteraan. Terangkan tiga (3) faktor yang mempengaruhi kekuatan subgred dalam pembinaan jalanraya.

Faktor yg mempengaruhi kekuatan s/gred1. jenis tanah2. Kandungan air3. pemadatan

A subgrade’s performance generally depends on three of its basic characteristics (all of which are interrelated):

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1. Load bearing capacity.  The subgrade must be able to support loads transmitted from the pavement structure.  This load bearing capacity is often affected by degree of compaction, moisture content, and soil type.  A subgrade that can support a high amount of loading without excessive deformation is considered good. 

2. Moisture content.  Moisture tends to affect a number of subgrade properties including load bearing capacity, shrinkage and swelling.  Moisture content can be influenced by a number of things such as drainage, groundwater table elevation, infiltration, or pavement porosity (which can be assisted by cracks in the pavement).  Generally, excessively wet subgrades will deform excessively under load.

3. Shrinkage and/or swelling.  Some soils shrink or swell depending upon their moisture content.  Additionally, soils with excessive fines content may be susceptible to frost heave in northern climates.  Shrinkage, swelling and frost heave will tend to deform and crack any pavement type constructed over them.

(6 markah)

(c) Tiga jenis gred agregat yang terdapat digunakan dalam campuran turapan lentur ialah;

(i) Gred seragam (Uniformly graded)

(ii) Gred sekata ( Well graded)

(iii) Gred jurang   (Gap graded)

Jelaskan ciri-ciri setiap gred yang dinyatakan di atas.

The properties of the aggregate gradation depends strongly on the distribution of aggregates sizes.There are several general types of aggregate gradations. (i) Uniform gradations have large percentages of one size. Few points of contactPoor interlock (shape dependentHigh permeability

(ii) Well graded aggregates have approximately equal amounts on each sieve in the stack. Good interlockLow permeability

(iii) Gap graded aggregates have large and small but few intermediate sizes.Only limited sizesGood interlock

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Low permeability

PEMBINAAN JALAN RAYA

S1. Terangkan tujuh (7 ) proses dalam kerja pembinaan jalan raya bermula daripada peringkat awal hingga akhir.

Jawapan: Kerja-Kerja Pembinaan Jalan Skop utama kerja-kerja pembinaan jalan adalah:-

i. Membersih tapakii. Kerja ukur tanah/setting outiii. Kerja tanah ; korekan, potongan, tambakaniv. Rawatan tanahv. Membina struktur jalanvi. Membina jambatanvii. Membina sistem saliranviii. Membina penahan tembokix. Membina perlindungan cerunx. Memasang/mengadakan perabot jalanxi. Memasang lampu jalan/lampu isyaratxii. Pengurusan alam sekitarxiii. Pengurusan Trafik

S2. (a) Describe three (3) factors which influence to the strength of sub-grade in road structure.

S2. (a) Terangkan tiga (3) faktor yang mempengaruhi kekuatan subgred dalam struktur jalan raya.Answer

Three (3) factors which influence to the strength of sub-grade in road structure. are listed as follows.

Three (3) The factors which influence to the strength of the sub-grade are listed as follows.

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1. Types of soils The most suitable soil are granular soil and the most unsuitable material for the sub-grade is the peat soils.2. Water content Suitable moisture content of soil is determined through laboratory compaction test. 3. The method and compaction effort

The strength of soil also depends on these factors and at site the type of plant used for the compaction and the number of repetition of compaction also been considered

(b) List four tests used to determine the suitability of soils as a sub-grade and road embankment .

Answer

The 4 tests are listed as follows:1Loss On Ignition (LOI) – BS 1377: Part 3: 19902Liquid Limit (LL) and Plastic Limit (PL) – BS 1377: Part 2: 19903Compaction Test – BS 1377: Test 13: 1975 (Part 4: 1990)4 California Bearing Ratio (CBR) – BS 1377: Test 16: 1975 (Part 4: 1990)

(c) Define compaction of subgrade. AnswerThe densification of material by means of mechanical manipulation.Compaction of subgrade.is a process by which the solid soil particles to be used as a road foundation are packed more closely together, usually by mechanical mean (rollers), with the intention of to increase the dry density of soil.

(d) What happen to density and void ratio during compaction. Answer

Increased in Density is reduces the amount of void without changing the volume and moisture content.

(e) How is it accomplished?

Answer A unifrom layer of 100 to 150mm of material is compacted with several passes of

heavy equipment, such as roller, until specified unit weigth is achieved. The dry density can be achieved by increasing the degree of compaction

(d) Describe four objectives of compaction.

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The objectives of subgrade compaction are:1. To increase the bearing capacity / shear strength.2. Reduce the soil settlement 3. Reduce the permeability (serapan air)4. Control the swelling and shrinkage (pengecutan)5. Increase soil durability (ketahanlasakan)

(e) Describe three properties of a good subgrade.

AnswerThe good sub-grade should have the properties as follows:

1 Should be stable under the varieties of vehicle load and climatic condition.2 The strength of the sub-grade should remain along the design period.3 The ability to drain water.

stabil di bawah pelbagai beban kenderaan dan cuaca mempunyai kekuatan yang berkekalan sepanjang hayat rekabentuk sebaik-baiknya dapat mengalirkan air.

Rajah S2(b) menunjukkan rajah skematik Loji Campuran Tong, nyatakan proses-proses yang terlibat di dalam loji tersebut.

Rajah S2(b)

Jawapan:

1. Cold Feed Bins – untuk menghasilkan nisbah campuran.2. Cold Feed Conveyor – mengangkut agregat ke drum pencampur.3. Automatic Weighing System – menimbang secara automatik berat agregat4. Asphalt Storage Tank – menyimpan asfal untuk pengeluaran satu hari.5. Asphalt Pump – memindahkan simen asfal daripada tangki simpanan asfal.6. Drum Mixer – agregat yang dipam dimasukkan ke loji pencampuran untuk

dipanaskan dan dicampurkan dengan gas panas.

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F ............................

Aras formasi

A ...................................

B ...................................C ...................................D ...................................E ...................................

7. Dust Collector – mengumpul debu yang dihasilkan daripada proses pengeringan.8. Hot-Mix Conveyor – mengangkut campuran asfal ke dalam silo.9. Mix Surge Silo – menyimpan dan mengeluarkan campuran asfal ke dalam lori di loji.10. Control Van – mengawal suis pembakaran agregat dan campuran asfal, mesin, tong

penyuap dan suis gear.

Nyatakan satu (1) fungsi bagi setiap lapisan turapan berikut:

(i) Lapisan Tapak(ii) Lapisan Pengikat

(i) Lapisan Tapak: lapisan galas beban yang utama. (1 markah)

(ii) Lapisan Pengikat: pengagih beban ke tapak jalan dan menyediakan satu lapisan asas yang rata di mana lapisan haus akan dihampar ke atasnya.Penggunaan bitumen Emulsi semakin luas berbanding dengan bitumen Cutback. Berikan dua (2) sebab kenapa penggunaan bitumen emulsi semakin meningkat berbading bitumen Cutback.

Emulsi CutbackPeraturan

alam sekitarMengandungi air Mengandungi bahan meruap

yang mencemarkan udaraPembaziran Tidak melibatkan proses

ruapanBila meruap, bahan bakar

berharga dibazirkan ke udaraKeselamatan Kemungkinan berlaku

kebakaran adalah kurangKemungkinan berlaku

kebakaran tinggi kerana terdapat takat likat yang rendah

Kegunaan Boleh digunakan pada jalan lembap

Memerlukan keadaan kering

Suhu Menggunakan suhu yang lebih rendah dan menjimatkan kos

Menggunakan suhu yang lebih tinggi oleh itu memakan kos

yang tinggi

Berdasarkan Rajah S2(a), labelkan lapisan turapan jalan boleh lentur tersebut.

Rajah S2(a)

A : Lapisan Penghausan

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B : Lapisan PengikatC : Lapisan TapakD : Lapisan Subtapa E : SubgredF : Lapisan Permukaan

S1. (a) What is the purpose of having road administration? Apakah tujuan pentadbiran jalan diwujudkan?

(5 marks/markah) (c) List the types of road authorities in Malaysia and briefly state their function and duties.

Senaraikan jenis-jenis pihak berkuasa jalan di Malaysia serta nyatakan fungsi dan tanggung jawab mereka secara ringkas.

(15 marks/markah)

S4. (a) In road construction, aggregates can be classified as fine aggregate or coarse aggregates. Explain the difference. Dalam pembinaan jalan, batu baur boleh dibahagi kepada dua kategori iaitu halus dan kasar. Terangkan perbezaanya.

(10 marks/markah) (b) Describe test or procedure usually used to verify the suitability of aggregates and test to be carried out to ensure the completed works in terms of specification compliances.

Jelaskan kaedah atau ujian yang digunakan untuk memastikan kesesuaian batu baur untuk pembinaan jalan seterusnya jelaskan juga ujian yang digunakan untuk memastikan kerja yang telah siap mematuhi piawaian yang telah ditetapkan.

(10 marks/markah)

S6. (a) Describe drainage components and their functions in a typical road and highway projects. Terangkan komponen-komponen saliran serta fungsinya dalam satu projek jalan atau lebuhraya yang tipikal.

(8 marks/markah)

S1. a) Nyatakan tujuan ujian CBR kepada subgred.b) Terangkan secara ringkas prosedur ujian CBR.c) Piawai CBR: pada kedalaman pen 2.5mm, beban = 13.24 kN; pada kedalaman 5 mm beban = 19.96. Jadual S1 menunjukkan dapatan ujian CBR ke atas sampel subgred. Tentukan nilai CBR subgred.

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The objective of the California Bearing Ratio test is to determine the CBR value for a soil under consideration as a pavement foundation.This value is a percentage comparison with the standard crushed rock from California. Thus this test is a comparison test.The CBR value is used to quantify the response of the pavement foundation and subgrade to loading. The standard crush rock from California values are as follows:

Jawapan: 1. Ujian CBR dilakukan dengan menusukkan piston ke permukaan sampel dengan

kecepatan 1mm/min. Catat beban dan kedalaman penetrasi. Gambarkan carta hubungan antara beban melawan kedalaman penetrasi.

Piawai CBR: pada kedalaman pen 2.5mm, beban = 13.24 kN; pada kedalaman 5 mm beban = 19.96.Nilai CBR sampel diperoleh dengan membandingkan beban pada kedalaman 2.5 dan 5 mm dan membandingkannya dengan beban piawai tersebut di atas: CBR = [Test unit load] / [Standard Unit Load] x 100 (%)

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Nilai CBR yang diambil adalah nilai pada kedalaman penetrasi 2.5mm. Namun bila nilai CBR pada kedalaman penetrasi 5.0 mm ternyata lebih besar, ujian harus diulangi. Bila pada pengujian ulangan ternyata nilai CBR pada 5.0mm tetap lebih besar dari pada CBR pada 2.5mm maka digunakan nilai CBR pada penetrasi 5.0mm.

S7 . Tentukan nilai CBR sampel agregat dalam Rajah S7.

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S8. Terangkan lima (5) tujuan mampatan tanah dalam pembinaan subgred untuk jalan raya.

There are five principle reasons to compact soil:

-Increases load-bearing capacity- Prevents soil settlement and frost damage- Provides stability- Reduces water seepage, swelling and contraction- Reduces settling of soil

S2 (a) Terdapat tiga jenis lapisan tapak Macadam yang boleh dibina.

(i) Terangkan secara ringkas jenis-jenis lapisan tapak tersebut.(ii) Jelaskan kelebihan dan kelemahan bagi setiap lapisan tapak tersebut.

(9 markah)

Jawapan:(i) Jenis-jenis lapisan tapak Macadam:

Macadam Ikatan Kering (1markah) Macadam Campuran Basah (1markah) Tapak Jalan Macadam Berbitumen (1markah)

(ii) Kelebihan dan kelemahan:Macadam Ikatan Kering

Kelebihan; tapak jalan jenis ini adalah pengasingan dapat dihindarkan dan kosnya yang rendah. (1markah)

Kelemahan; cuaca-hujan menyebabkan aggregat halus basah dan tidak dapat mengisi rongga. (1markah)

Macadam Campuran Basah Kelebihan; tidak berlaku pengasingan, mudah dikerjakan dan mudah dipadatkan.

(1markah) Kelemahan; setiap lapisan yang dipadatkan perlu diberikan masa untuk kering.

(1markah)

Tapak Jalan Macadam Berbitumen Kelebihan; agihan beban yang baik, pengurangan tebal lapisan tapak, perlindungan

lapisan subtapak dan subgred. (1markah) Kelemahan; kos agak tinggi. (1 markah)

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(c) Rajah S2 menunjukkan skematik Loji Campuran Drum, terangkan kaedah yang digunakan di dalam loji tersebut bagi menghasilkan campuran yang digunakan.

(11 markah) Kaedah

i. Agregat dibawa dari longgokan menggunakan jengkaut kedalam corong tuag penyuap sejuk.

ii. Agregat jatuh dibawah corong tuang melalui getaran atau tarikan graviti keatas sabuk penghantar (conveyor belt) dan dihantar ke penaik sejuk. Nisbah pencampuran agregat dilaras menggunakan pintu boleh laras dan penyuap berbilang kelajuan.

iii.Penimbang otomatik pada penaik sejuk menimbang agregat secara berterusan semasa dihantar ke dram pengering.

iv. Dalam bilik kawalan pelarasan berat terhadap lembapan dibuat dan berat bitumen dipam mengikut kadar yang sesuai ke dram.

v. Agregat dikeringkan dan dipanaskan pada penghujung permulaan dalam dram dan bergerak kebawah dimana pada 1/3 hujung akhir dram bitumen dan pengisi dimasukkan.

vi. Bitumen menyalut agregat dan pracampuran dihantar keluar melalui hujung dram ke penaik bancuhan panas.

vii. Dari sini pracampuran dihantar ke tong simpanan bancuhan dimana ianya akan disimpan atau dimuatkan ke dalam lori angkut.

viii. Kadar pengeluaran biasanya sekitar 300 tan/jam.

S3 (a) Berikan 2 perbezaan antara turapan lentur dan turapan tegar.

1. Hayat rekabentuk turapan tegar lebih lama, iaitu 40 tahun berbanding turapan lentur hanya 10 tahun (JKR).

2. Kurang kerja penyenggaraan perlu dilakukan ke atas turapan tegar berbanding turapan boleh lentur.

3. Bahan mentah utama untuk binaan turapan tegar mudah didapati dalam negara (Malaysia).

4. Turapan tegar kebolehantelapan rendah, kecuali pada sambungan.5. Turapan tegar mampu menanggung beban gandar yang sangat berat6. Kos permulaan binaan turapan tegar adalah tinggi berbanding turapan lentur.7. Turapan tegar sukar dikorek atau ditebuk setelah terbina berbanding turapan boleh

lentur. Oleh itu menyukar kerja-kerja pemasangan utiliti dibawah turapan atau tanah.8. Proses dan kaedah pembinaan turapan tegar melibatkan tenaga mahir, dan jentera

yang berteknologi tinggi.

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(1) Pilih hayat rekabentuk turapan

(6) Pilih bahan yang akan digunakan pada setiap lapisan(7) Dapatkan ketebalan rekabentuk setiap lapisan turapan

(4) Dapatkan beban bertokok lalu lintas sepanjang tahun(5) Tentukan jenis dan kekuatan subgred

(2) Dapatkan kadar pertumbuhan tahunan lalu lintas(3) Dapatkan jumlah kenderaan perdagangan sehari searah

(8) Nyatakan struktur turapan yang dihasilkan

9. Sifat ketegaran papak mengorbankan sedikit keselesaan memandu teta[i tidak [ada turapan boleh lentur

10. Memerlukan penyenggaraan yang rapi pada sambungan turapan tegar demi kekuatan dan kelanjutan usia turapan tegar.

(mana-mana 2 di atas: 2 markah)

S3 (b) Jelaskan proses rekabentuk ketebalan struktur turapan dalam bentuk carta alir.

S4 (a) Terangkan secara ringkas tiga (3) fungsi bahu jalan.(3 markah)

Antara fungsi utama bahu jalan ialah:1. Berhenti kecemasan2. Kenderaan berhenti atas pelbagai sebab3. Ruang mengelak atau mengurangkan kemalangan yang lebih teruk4. Keselesaan dan kemudahan pemanduan disebabkan sense of openness yang ada

pada bahu jalan dengan lebar yang mencukupi5. Meningkatkan keselamatan dengan meningkatkan jarak penglihatan

(1 jawapan=1m)

(b) Terangkan tiga (3) prinsip pembinaan pembahagi jalan. (6 markah)

Prinsipnya adalah untuk:1. menyediakan kebebasan yang diperlukan daripada gangguan atau konflik

dengan kenderaan dari arah bertentangan

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2. menyediakan ruang atau kawasan pemulihan (recovery) untuk kenderaan yang terbabas atau di luar kawalan

3. menyediakan untuk penukaran kelajuan dan ruang untuk kenderaan membelok ke kanan

4. menyediakan ruang untuk penambahan lorong di masa akan datang(1 jawapan=2m)

(c) Rajah S4 menunjukkan (superelevation) bagi jalan raya mendatar sejajar, bincangkan konsep yang mana membolehkan kenderaan untuk berada pada lengkung dengan selamat pada kelajuan lebih tinggi

(5 markah) Tujuan menggunakan superelevation keratan rentas jalan adalah untuk

mengimbangi daya emparan, atau menarik keluar, untuk kenderaan menyeberangi lengkung mendatar (3 markah)

Geseran Sisi dibangunkan antara tayar dan permukaan jalan untuk mengimbangi keluar kenderaan (2 markah)

REKABENTUK KETEBALAN TURAPAN LENTUR

Q1. Design a road pavement for a 2-lane highway with an average daily traffic of1350 vehicles, 16% of which are commercial vehicles with an un-laden weight >1.5 tons.Q2. Describe 4 Design Factors considered in pavement thickness by all design methods

1 Traffic Loading (heavy trucks)1. Soil Subgrade Strength2. Pavement Materials Characteristics (strengths of materials comprising the pavement

build-up)3. Environmental Conditions (Its effect on soil and pavement material strength)

Q3. The method of design provided in the New JKR Method includes consideration of the following :

1. Pavement performance,2. Traffic, std axle3. Roadbed soil – soil CBR, Elastic Modulus 4. Materials of construction –surfacing, base , sub base5. Environment -temperature,

Q4. Describe five (5) Thickness Design Inputs based on JKR new Design Method.

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1. Performance Period (years) – no The period of time used in determining pavement thickness and as the basis for forecasting future traffic loads; typically assumed to be20 years in length.

2. Soil Strength –CBR as a measure the measure of soil strength, accounting for seasonal variation in soilstrength;

3. Traffic Loading Over the Performance Period o Measured in Equivalent 18,000 lb.Single Axle Loads (ESAL or W18); o ESAL is a means by which the pavement damage caused by different axle configurations and truck weights can be normalized; For determining the pavement thickness use the accumulated ESALs over the Performance Period.

4. Traffic Loading Consider directional distribution of heavy trucks (i.e. is the truck traffic consistent both directions? If no, design for direction with heaviest traffic.)

5. Geometric Design - Lane Factor – for multilane pavements design the thickness based on the lane that carries the greatest number of trucks.

- Terrain Conditions

4. (a) Terangkan maksud pemadatan dalam kerja tanah. Bincangkan factor-faktor yang mempengaruhi darjah pemadatan

(10 markah) (b) Sebutkan TUJUH aktiviti yang terlibat dalam kerja tanah untuk

pembinaan jalanraya serta peralatan utama yang digunakan untuksetiap aktiviti tersebut.

(10 markah)

5 . (a) Sebutkan prinsip-prinsip yang diutarakan oleh John Macadam (1756)dan Thomas Telford (L757) dalam pembinaan jalan raya. Selanjutnya lakarkan struktur turapan Macadam dan Telford.

(10 markah)(b) Terangkan faktor-faktor yang mempengaruhi rekabentuk turapan.

(10 markah)

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S1. (a) Rajah S1(a) menunjukkan lapisan bagi struktur jalan raya turapan lentur. Labelkan

struktur yang ditunjukkan oleh anak panah.

Rajah S1(a)

(8 m)

(b) Terangkan dengan jelas fungsi setiap perkara berikut dalam pembinaan jalan raya:

(i) Fungsi Pemadatan tanah untuk subgred jalan rayaThere are five principle reasons to compact soil: - - Increases load-bearing capacity- Prevents soil settlement and frost damage- Provides stability- Reduces water seepage, swelling and contraction- Reduces settling of soil

(ii) Fungsi Lapisan Sub TapakLapisan Sub Tapak( Subbase Course) .

- between base course and subgrade. - Function as Structural support - minimize the intrusion of fines from the subgrade into the pavement structure and improve drainage. - consists of lower quality materials than the base course but better than the subgrade soils. - Subbase courses are generally constructed out of crushed aggregate or engineered fill.

Sub gred

Bebendul

PenahanBebendul

Lapisan penghausan

Lapisan pengikat

Tapak jalan

Sub tapak

Aras formasi

penghausan

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(iii) Fungsi Ujian Nisbah Galas California (California Bearing Ratio Test)Tujuan

Untuk mendapatkan nilai kekuatan sesuatu lapisan turapan yang akan

menanggung beban lalulintas dalam menyediakan rekabentuk struktur

turapan jalan raya atau lapangan terbang. Ujian dilakukan ke atas bahan

yang melepasi ayak 20.0 mm.

Process A sample of the material that needs testing is loaded into our mould, either on site or in our laboratory. Then a 3sq inch (approx. 50mm dia) plunger is loaded against the sample and the penetration into the sample is measured at various increments.

Results are expressed in relative terms, as a percentage of the determined value of 3000lbf to penetrate 0.1inch (2.5mm at 13.3KN in today’s terms) in the originals tests. In modern construction, the required CBR value is specified for soils and fill from formation level up through granular fills to the sub-base immediately below a concrete slab or asphalt road. The actual requirements will be determined by the Design Engineer but typical values might be 3-5% for clay formation or 15-30% for Type 1 sub-base.

Advantages 1. The tests are relatively quick and inexpensive. 2. They can be performed in the laboratory or on site on undisturbed or re-

compacted samples. 3. Results can be obtained within a day. 4. We can perform these tests on a self-contained basis (although the assistance of

an excavator on site is often helpful). (12 m)

S2 (a) Nyatakan EMPAT (4) ciri agregegat sesuai untuk bahan asfal konkrit

campuran

panas lapis penghausan (Hot Mix Asphalt wearing course)

(4 m) Ciri-ciri agregat untuk turapan Hot Mix Asphalt wearing course adalah;

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1. Kekuatan – untuk menahan tindakan jentera pembinaan dan beban lalulintas.

2. Ketahanan – tidak mudah pecah, merekah atau berkeping dibawah tindakan cuaca.

3. Bentuk dan tekstur permukaan yang baik – untuk memberikan kekuatan dan kestabilan melalui sifat saling mengunci dan rintangan terhadap anjakan.

4. Kebersihan dan ketulenan – mengekalkan keseragaman dan kualiti campuran.

5. Afiniti terhadap bitumen – memastikan campuran tahan lasak dan mempunyai ikatan yang baik dengan bahan pengikat.

6. Penyerapan air rendah – memudahkan kerja pengeringan dan pencampuran serta mengelakkan tanggalan pengikat.

7. Tahan pengilapan – memastikan turapan mempunyai rintangan gelinciran yang mencukupi dan tidak mudah tergilap.

8. Penggredan yang baik – memastikan campuran mempunyai taburan saiz yang sesuai bagi mengekalkan mutu dan kekuatan turapan.

(b) Ciri fizikal utama bagi agrgregat untuk tujuan pembinaan jalan raya

termasuk dalam senarai (i) hingga (vi). Terangkan secara ringkas sebab

setiap ciri dalam senarai (i) hingga (vii) perlu dinilai bagi menjamin kualiti

bahan agregat.

(i) Penggredan (Gradation) Penggredan yang baik – memastikan campuran mempunyai taburan saiz yang sesuai bagi mengekalkan mutu dan kekuatan turapan.

(ii) Keliatan dan Rintangan Lelasan (Toughness and Abrasion Resistance)

• Kekuatan – untuk menahan tindakan jentera pembinaan dan beban lalulintas.• Ketahanan – tidak mudah pecah, merekah atau berkeping dibawah tindakan

cuaca.• Resistance to wear• Important

Pavement surfaces – agg. Not get rounded or polished due to trafficFloors – subject to heavy trafficRoadbeds – subjected to innumerable cycles of lad application and removal

(iii) Graviti Tentu (Specific Gravity)Kebersihan dan ketulenan – mengekalkan keseragaman dan kualiti campuran

• Necessary to measure accurately the volumes occupied by the aggregate and any water that might have seeped into the pores in the particles

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•(iv) Bentuk Zarah dan Permukaan Tekstur (Particle Shape and Surface Texture)

• Bentuk dan tekstur permukaan yang baik – untuk memberikan kekuatan dan

kestabilan melalui sifat saling mengunci dan rintangan terhadap anjakan. Particle shape and surface texture

• Affect the strength and bond with cementing materials• Resistance to sliding of one particle over another• Flat –thin or long needle shaped particles break more easily• Rough faces allow a higher friction strength•

(v) Ketahanan dan Kekukuhan (Durability and Soundness)• Tahan pengilapan – memastikan turapan mempunyai rintangan gelinciran yang

mencukupi dan tidak mudah tergilap.• Kekuatan – untuk menahan tindakan jentera pembinaan dan beban lalulintas.• Ketahanan – tidak mudah pecah, merekah atau berkeping dibawah tindakan

cuaca.

(vi) Kebersihan dan bahan mudarat (Cleanliness and Deleterious Materials)

• Deleterious substances – Harmful or injurious materials– Include weak or low quality particles and coatings that are found on the

surface of aggregate particles– Include

• Organic coating• Dust• Clay lumps• Shale• Coal particles• Friable particles easyt o crumble• Chert may break up when exposed to freezing and thawing• Badly weathered particles • Soft particles• Lightweight particles

(16 m)

S3 (a) Senaraikan LIMA (5) ciri bitumen gred penetrasi 80-100

Ciri Bitumen Gred Penusukan 80-100

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1. Pada suhu bilik ianya berwarna hitam, melekit, berkeadaan separa pepejal

2. Bahan yang sangat likat3. Bahan penyimenan yang kuat & tahan lama dengan ciri rekatan &

kalis air yang sangat baik4. Rintangan yang sangat tinggi terhadap tindakan kebanyakan asid,

alkali & garam5. Kegunan utama dalam penghasilan campuran panas yang digunakan

untuk pembinaan turapan anjal6. Dicairkan dengan memanaskannya untuk dicampur bersama agregat

membentuk campuran panas & apabila sejuk campuran ini akan membentuk turapan yang sangat kuat

7. Pengkelasan dilakukan melalui ujian penusukan @ ujian kelikatan8. Gred bitumen penusukan mengikut:9. Ujian penusukan – antara 40 ke 30010. Kelikatan – 5 ke 40

(4 m)

(b) Nyatakan tujuan dan berikan prosedur ringkas ujian titik lembut (softening point).

(4 m) Titik Lembut (Softening Point) (AASHTO T 53-4)

Tujuan – menentukan suhu di mana pertukaran fasa berlaku dalam bitumen

- Definisi – suhu di mana bitumen tidak berupaya untuk menyokong berat bebola besi dan mula mengalir

- Dikenali sebagai ujian cincin & bebola- Ujian ini digunakan bersama ujian penusukan untuk menentukan nilai

Indeks Penusukan (IP) sesuatu bitumen.- IP digunakan untuk menganggar ciri viscoelastik bitumen & bancuhan- Ini akan menentukan kesesuaian sesuatu bitumen sebagai bahan

turapan jalan- IP = (1951.4 – 500 log P – 20 SP) / (50 log P – SP – 120.14)- Biasanya IP antara -1 dan +1 sesuai untuk pembinaan jalan raya

Prosedur Ujian softening point Bitumen dipanaskan & dituang ke dalam sepasang cincin Selepas disejukkan, cincin diapungkan dalam bekas berisi air

pada suhu 5°C. Bebola keluli diletakkan ke atas sampel bitumen tadi & air

dipanaskan perlahan-lahan Bila suhu meningkat, bitumen mula melembut dan bebola

tenggelam ke dalam bitumen Bebola kemudiannya jatuh melalui cincin hingga menyentuh

plet yang berada 25.4mm di bawahnya Suhu apabila bebola menyentuh plet diambil sebagai titik

lembut bitumen

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(c) Terangkan kegunaan bahan tack coat dan prime coat dalam pembinaan jalan raya.

(4 m)

(d) Bincangkan dengan jelas jenis dan fungsi setiap bahan yang di gunakan dalam campuran konkrit asfal Asphalt Concrete Wearing Course.

(4 m)Generally, hot-mix asphalt concrete mixture consists of asphalt cement

(AC60/70 or AC 80/100 are most common), fine aggregate (sand), and coarseaggregate (crushed limestone)

• The quality and proportion of each of these components plays an importantrole in the property and durability of the finished asphalt pavementRequired properties of the pavement are:• Stability – is the strength of the pavement to resist deformation undertraffic load. It comes from aggregate interlocking and asphalt cohesions• Durability – is the resistance of the pavement against disintegration

eitherby weathering of asphalt or mechanical breakdown of aggregate.• Flexibility – is the ability to withstand deformations without cracking• Skid Resistance – is the ability of the pavement to provide long-lasting

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nonskid surface. Pavement bleeding and aggregate polishing is the two main

sources of slippery surfaceCompromise is needed for the property of asphalt, aggregate, and theamount of air voids in the asphalt mixture

JENIS DAN FUNGSI SETIAP BAHAN

(e) Bincangkan perbezaan ciri bitumen cutback dengan bitumen emulsi.(5 m)

Cutback- Bitumen cecair yang dihasilkan dengan mencampurkan bitumen (50 –

80%) dengan cecair pelarut petroleum- Terbahagi kepada 3 mengikut kadar ruapan

a) Awet cepat (Rapid Curing – RC) campuran bitumen dengan bahan pelarut yang cepat meruap digunakan sebagai salut jejalur & rawatan permukaan

b) Awet Sederhana (Medium Curing – MC) Campuran bitumen dengan bahan pelarut yang meruap pada

kadar sederhana seperti kerosin Digunakan sebagai salut perdana, campuran sejuk untuk kerja

tampalan & proses pencampuran jalanc) Awet Perlahan (Slow Curing – SC)

Campuran bitumen dengan bahan pelarut yang lambat meruap seperti disel

Digunakan sebagai salut perdana, campuran sejuk untuk kerja tampalan dan pengurang debu

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Contoh singkatan yang biasa digunakan : MC – 70 = bitumen cutback jenis awet sederhana dengan kelikatan kinematik minimum 70 sentistokes

Emulsi- Bitumen cecair hasil campuran bitumen (55 – 65%) dengan air &

bahan emulsi dalam pengisar koloid.- Merendahkan kelikatan bitumen – membolehkannya digunakan pada

suhu yang lebih rendah- Jenisnya bergantung kepada agen pengemulsi

Anionik – Globul bercas negative yang terhasil apabila agen pengemulsi bercas positif digunakan iaitu dari jenis alkali. Ianya sesuai digunakan bersama agregat bercas positif seperti batu kapur

Kationik – Globul bercas positif yang terhasil bila agen pengemulsi bercas negatif digunakan iaitu jenis berasid. Ia sesuai digunakan bersama agregat bercas negatif seperti batu pasir, kuarza & agregat bersilika

Terbahagi kepada 3 berdasarkan kadar set yang bergantung kepada jenis peratus kandungan agen emulsi yang digunakan

▬ Set Cepat (RS) – rawatan permukaan, salut jelujur dan Macadam penusukan

▬ Set Sederhana (MS) – Macadam penusukan, campuran sejuk gred terbuka

▬ Set Perlahan (SS) – salut jelujur, campuran sejuk gred tumpat & tampalan retak

Perbandingan Emulsi semakin meluas berbanding Cutback kerana :

  Emulsi Cutback

Peraturan alam sekitar

Mengandungi air Mengandungi bahan meruap yang mencemarkan udara

Pembaziran Tidak melibatkan proses ruapan

Bila meruap, bahan bakar berharga dibazirkan ke udara

Keselamatan Kemungkinan berlaku kebakaran adalah kurang

Kemungkinan berlaku kebakaran tinggi kerana

terdapat takat kilat yang rendah

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Kegunaan Boleh digunakan pada jalan lembah

Memerlukan keadaan kering

Suhu Gunakan suhu yang lebih rendah dan menjimatkan

kos

Sebaliknya

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ASPHALT MIX DESIGN What is a mix design? Basically, its just a recipe for making hot mix.

What are the ingredients?

Well first you need a binder: That would be the asphalt cement

What’s being bound together? That would be the aggregate

The objective of the design process is to “determine the proportions of asphalt cement and aggregate that will give long lasting performance as part of the pavement structure”

OBJECTIVES “to determine a cost-effective blend and gradation of aggregates and asphalt (cement) that yields a mix having:

1. sufficient asphalt (cement) to ensure a durable pavement

2. sufficient mix stability to carry traffic without distortion or displacement

3. sufficient voids in the total compacted mix to allow for a slight amount of asphalt expansion due to temperature increases without flushing, bleeding and loss of stability

4. a maximum void content to limit the permeability of harmful air and moisture into the mix

5. sufficient workability to permit efficient placement of the mix without segregation and without sacrificing stability and performance

6. for surface mixes, proper aggregate texture and hardness to provide sufficient skid resistance in unfavourable weather conditions”

To determine the Percentage of Optimum Binder Content

the percent asphalt cement is in terms of the total mix mass in this course

in order to get the right balance between aggregate and binder we need to know some the basic property of the aggregate is its grain size distribution or gradation

properties of these materials

this, more than any other property will affect the performance of the mix

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Wearing Surface Course Mixtures for wearing surfaces, so fine aggregate needed to give a smoother texture

must still have sufficient stability and durability for traffic loads

Maximum Particle Sizes range between 9.5 mm and 19 mm (⅜” to ¾”)

open-graded friction course (OGFC), a.k.a. porous friction course or popcorn mix used to reduce hydroplaning and increase skid resistance

Binder Course Mixtures intermediate layer between surface and base

larger Maximum Particle Sizes 19 mm - 38 mm (¾” – 1 ½”)

can be used as a base course or as a surface course where heavy wheel loads and tight radius power steering turns are involved such as is port facilities, logging yards and industrial loading docks

can be placed directly on compacted subgrade or over a granular base

Maximum Particle Sizes range up to 75 mm (3”)

larger particle sizes result in higher stability in dense-graded mixes and facilitate drainage in open-graded mixes

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