The effect of joint width between blocks in concrete block pavement

Jointing sand is the main component of concrete block pavement (CBP) that promotes load transfer between blocks. Often, when sands are available from various sources, it becomes a difficult task to judge the right source of sand. This paper presents the results of an experimental program, conducted to demonstrate a quick and simple technique, for selecting the right source of jointing sand for CBP. The optimum joint width between blocks is 3 mm. For joint widths less than the optimum, the jointing sand was unable to enter between blocks. A large amount of sand remained outside the joint sand heaps on the block surfac

The effect of thickness and laying pattern of paver on concrete block pavement

In concrete block pavements, the blocks make up the wearing surface and are a major load-spreading component of the pavement. Earlier findings were inconsistent with respect to the deflection response of concrete blocks in the pavement. This research investigate the anchor beam spacing of concrete block pavement (CBP) on sloping road section based on the degree of slope, laying pattern, blocks shape, blocks thickness, joint width between blocks and bedding sand thickness. The effect of load transfer on the CBP behaviour is discussed. The results of a series of tests conducted in laboratory with horizontal force test and push-in test in several degrees of slopes. The horizontal force testing installation was constructed within the steel frame 2.00 x 2.00 metre and forced from the side until CBP failure (maximum horizontal creep). For the applied push-in test in a rigid steel box of 1.00 x 1.00 metre square in plan and 0.20 meter depth, the vertical load was increased from zero to 51 kN on the CBP sample in 0%, 4%, 8% and 12% degrees of slopes. The herringbone 45o is the best laying pattern compared to herringbone 90o and stretcher bond to restraint the horizontal force, which the blocks contribute as a whole to the friction of the pavement, the blocks being successively locked by their rotation following their horizontal creep. This reduces the incidence of creep and distributes wheel loads more evenly to the underlying pavement construction. The uni-pave block shape has more restraint of horizontal creep than rectangular block shape, because uni-pave block shape has gear (four-dents), while rectangular block shape has no gear (dents).The difference in deflections observed between uni-pave shape and rectangular shape are small. The change in block thickness from 60 to 100 mm significantly reduces the elastic deflection of pavement. Thicker blocks provide a higher frictional area. The load transfer will be high for thicker blocks. The response of the pavement is highly influenced by block thickness. The optimum joint width between blocks is 3 mm. For joint widths less than the optimum, the jointing sand was unable to enter between blocks. A large amount of sand remained outside the joint sand heaps on the block surface. The relationship between push-in force with block displacement on the varying loose thicknesses of 30, 50, and 70 mm bedding sand, shows that the deflections of pavement increase with increase in loose thickness of bedding sand. The deflection is minimum at a loose thickness of 30 mm bedding course. The higher the loose bedding sand thickness, the more the deflection will be. The effect of the degree of slope on concrete block pavements on sloping road section area is significant with friction between blocks and thrusting action between adjacent blocks at hinging points is more effective with thicker blocks. Thus, deflections are much less for thicker blocks with increasing degree of the slope. The spacing of anchor beam is increases with decreasing joint width, degree of slope and bedding sand thickness. To compare results between laboratory test with the simulated mechanical behaviour of concrete block pavements, a structural model based on a Three Dimensional Finite Element Model (3DFEM) for CBP was employed

Permanent deformation of concrete block pavements under highway accelerated loading

Experiment concrete block pavements (CBP) are essential to study and assess the structural pavement performance. Accelerated loading testing is able to determine the pavement response and performance under a controlled, accelerated, accumulation of damage in a compressed time period. A test was performed in laboratory to investigate the permanent deformation development under Highway Accelerated Loading Instrument (HALI). A CBP model constructed from the bottom with hard neoprene, bedding sand and paving blocks filled with jointing sand was prepared and tested. Up to 2500 cycles load repetitions of a 1000 kg single wheel load were applied to the pavement model. The pavement deformation development was studied through its transverse deformation profile, mean rut depth in the wheel path, longitudinal rut depth profile and joint width between paving blocks. Test results indicated that the rut depth increase with increasing number of load repetitions and also the heaves at each side of the wheel path. It has also shown that the constant deformation, accelerating and braking sections of the pavement have been observed and determined

Effect of open-graded coarse aggregate on concrete paving blocks properties for pavement

The potential of using coarse aggregate for open graded in the production of concrete paving blocks (CPB) were presented in this study. Three different sizes of coarse aggregate were used through the investigation: (a) passes 8 mm retains 5 mm, (b) passes 10 mm retains 8 mm and (c) passes 10 mm retains 5 mm as control. Furthermore, a series of tests were carried out to determine the properties of the blocks, namely density, porosity, weight loss, compressive strength and skid resistance test. It was found that the size of coarse aggregate effects on many aspects, especially in the strength of the blocks. However, at the same time it also provides sufficient strength or the minimum required strength (30 MPa) for a rectangular block to be used as part of paving surface. In addition, the blocks show that it is suitable for use in vehicle area when the value of the British Pendulum Number of skid resistance test more than 45 referred to BS 6717; 2001

Highway accelerated loading instrument (HALI) testing on permanent deformation for concrete block pavement

Experiment concrete block pavements (CBP) are essential to study and assess the structural pavement performance. Accelerated loading testing is able to determine the pavement response and performance under a controlled, accelerated, accumulation of damage in a compressed time period. A test was performed in laboratory to investigate the permanent deformation development under Highway Accelerated Loading Instrument (HALI). A CBP model constructed from the bottom with hard neoprene, bedding sand and paving blocks filled with jointing sand was prepared and tested. Up to 2500 cycles load repetitions of a 1000 kg single wheel load were applied to the pavement model. The pavement deformation development was studied through its transverse deformation profile, mean rut depth in the wheel path, longitudinal rut depth profile and joint width between paving blocks. Test results indicated that the rut depth increase with increasing number of load repetitions and also the heaves at each side of the wheel path. It has also shown that the constant deformation, accelerating and braking sections of the pavement have been observed and determine

Performance of concrete block pavement on sloped road section

The construction of Concrete Block Pavement (CBP) on slopes provides interesting challenges for road engineers. The horizontal (inclined) forces exerted on the road surface are greatly increased due to traffic accelerating (uphill) and braking (downhill). These forces will cause horizontal creep of the blocks down the slope, resulting in opening of joints at the top of the road section. The objective of this study was investigate the effect of parameters include degree of slope, laying pattern, joint width, and thickness of paving block on the performance of CBP on slopes. A laboratory-scale test was used to study these parameters based on steel frame horizontal force and push in tests. Three different laying pattern (stretcher bond, herringbone 90o and herringbone 45o) and joint width (3 mm, 5 mm and 7 mm) were used in the test program. The pavement responses are characterized in terms of horizontal creep and deflection due to applied load for half of an allowable single axle limit. The results indicate that herringbone 45o laying pattern and 3 mm joint width performed best on slopes section. The 100 mm paver thickness is found to be more stable than 60 mm thickness from aspect horizontal force resistant. The results also indicate that the increase of the slope increase the horizontal creep, but decrease of the pavement displacement

The Analysis of Stress Distribution on the Physical Model of Road Base Layer

The road base layer as a primary foundation for the flexible pavement needs to provide adequate strength for the working load. The road base layer which is constructed from a gradation of aggregate must distribute the stress as wide as possible to reduce the load per square area. The action of stress distribution on the road base layer mostly relies on its grain-to-grain interaction. This research used the natural crushed aggregate (NCA) and the recycled concrete aggregate (RCA) as the road base materials. Physical models were conducted to evaluate the stress distribution under a static load. The physical model was using a box with a dimension of 620 mm x 620 mm x 500 mm. There were three layers for the physical model such as the road base layer, sub-base layer, and subgrade layer. The thickness of each layer was 200 mm, 100 mm, and 200 mm respectively. A static load with a maximum of 20 kN in the increment of 1 kN was added. The result of the scaled-model was not as similar to the theory of Boussinesq related to the stress distribution. The characteristic of the materials will show a different behavior of the stress distribution

Strength and microstructure properties of double layered concrete paving blocks containing waste tyre rubber granules

This paper aims to examine the effect of replacing the natural aggregate with waste tyrerubber granules. Waste tyrerubber granules were used as aggretate replacement in the pavingblock at four different percentage: 10%, 20%, 30%, and 40%. The paving blocks were tested in terms of their strength and the characteristics of their microstructure by measuring compressive strength, flexural strength, splitting tensile strength, and skid resistance. Field scanning electron microscopy (FESEM) and Fourier Transform Infra- Red(FTIR) analysis werecarried out on the paving block specimen. When 10% of the natural aggregate was replaced with waste tyrerubber granules, there was no substantial difference in the compressive strength but the flexural and splitting tensile strength increased to a certain extent. When more than 20% of waste tyrerubber granulesis incorporated in the paving blocks, the strength is acutely reduced even though there is a growth in ductility. The results proved that even after failure, the paving blocks did not shatter but still stayed imperforated. Double layer rubberized concrete paving blocks (DL-RCPBs) are more flexible and soft to the surface, and thus provide a better ride quality. This characteristic makes it suitable for trafficked roads. DL-RCPBs (30% and 40%) with low strength characteristics could be used on roads that not required high strength and may be viable for other applications, depending on the percentage of waste tyre rubber used. DL-RCPB with higher waste tyre rubber content exhibit higher skid resistance especially on dry surface but reduced on slippery surface. Two main factors that influence the skid resistance are high elasticity and rough surface texture of waste tyre rubber. It is suggested that DL-RCPBs could be introduced as one of alternative concrete paving block (CPB) that can be used in paving application

Properties of asphaltic concrete containing sasobit®

With increasing interest in the use of hot mix asphalt in the paving industry, more studies in this field for improvement of hot mix asphalt properties seem to be necessary. Hence, the main objective of this study was to investigate the effect of sasobit® content as modified binder in hot mix asphalt. 60/70 penetration grade asphalt was separately modified with sasobit® at different concentrations ranging from 0% to 4.5%. The influence of sasobit® on the hot mix asphalt mixtures properties were detected through conventional tests i.e. penetration and softening point. In addition, the Marshall stability, abrasion loss, and resilient modulus were also examined. Results indicated that the hot mix asphalt containing Sasobit® additive has significant affect in terms of penetration and softening point. Furthermore, the addition of Sasobit® seemed to improve the stability, abrasion loss and modulus of stiffness

Prediction of sound absorption coefficient for double layer rubberised concrete blocks

Nowadays rubberised concrete is used to support construction sustainability and contribute to a better development of efficient construction material, in particular by using waste rubber tyre. The use of rubber in block pavement is one of the actions in order to reduce the noise from tyre-road interaction and hence able to reduce pass by noise pollution. In this paper, the influence of waste rubber tyre as the replacement for aggregate on the sound absorption coefficient of double layer rubberised concrete blocks was investigated. Non acoustics and acoustics experimental investigations were carried out on a series of block with thickness of 80 mm with facing layer (FL) of block varies in thickness from 10 to 40 mm. FL and bottom layer consist of concrete mixture containing waste tyre rubber granules (RG) of 5 mm to 8 mm and 1 mm to 4 mm, respectively as replacement of natural aggregate within the range of 10-40%. The ratio for cement: aggregate: sand was 1: 1.7:1.5 and water to cement (w/c) ratio of 0.47. Noun acoustics parameters include density, compressive strength, water absorption and porosity. Acoustic parameters investigation of specimens of double layer block showed that concrete pavement blocks have maximum sound absorption located at low frequency of 500 to 700 Hz. This indicates that it is suitable for application of mitigation of low speed traffic condition. A model was developed to predict the maximum sound absorption coefficient of the double layer block pavements which included the percentage of rubber content, thickness of FL and porosity as statistically significant predictor (p < 0.05). This would benefit the road engineers in managing traffic noise management as the sound absorption coefficient is the key important element in reducing tyre/road interaction noise