Properties Of Roller Compacted Concrete Pavement Research Articles

Experimental investigation on mechanical properties of sustainable roller compacted concrete pavement (RCCP) containing waste rubbers as alternative aggregates

Different types of solid waste are generated every year due to global industrialization. With the rapid growth of the automobile industry, the disposal of billions of waste rubbers (WR), which pollute the environment and cannot be disposed of properly, is emerging as an urgent matter of concern. Recycling waste rubbers by using them on pavements will contribute to the elimination of ecological and economic problems. In this study, the effects of waste rubbers on the mechanical properties of roller-compacted concrete pavement (RCCP) were investigated by obtaining sustainable RCCP mixtures using different types of waste rubbers as coarse and fine aggregate substitutes. In this context, waste rubbers with three different sizes (powder, crumb and shredded) were substituted for aggregate by volume at seven levels (0%, 2.5%, 5%, 7.5%, 10%, 20% and 30%) with a maximum of 30% in RCC mixtures. Unit weight, mechanical properties, modulus of elasticity and ultrasonic pulse velocity (UPV) were evaluated and compared according to the waste rubber content in the RCC mixtures. In addition, microstructural analysis of the mixtures was performed through scanning electron microscopy (SEM). The experimental results revealed that the compressive, flexural and splitting tensile strength and modulus of elasticity decreased with increasing waste rubber content in RCC. The utilization of waste rubber increased the ductility of RCC and decreased the density to produce lighter concrete. RCC with a compressive strength of about 30 MPa could be obtained by substituting 10% of waste rubber for aggregate. Thus, the utilization of high waste rubber content in pavements was feasible. This study can contribute to a more sustainable RCCP production by replacing natural aggregates with waste rubbers.

Comparative Study between Recycled Fine and Coarse Aggregate Used in Roller Compacted Concrete Pavement

To decrease the impact on the environment of building waste, the recycled aggregate may be used in various sustainable engineering applications, such as roller compacted concrete pavement (RCCP). This research examined how using recycled aggregate as a partial replacement for natural aggregate as coarse or fine affected the mechanical properties of roller-compacted concrete pavement. The recycled aggregate was crushed and sieved to coarse and fine aggregate before being used in the roller-compacted concrete pavement. Compressive strength, splitting tensile strength, and flexural strength were all evaluated after the samples were prepared at 28 and 90 days of curing. According to the study's findings, the partial replacement of coarse or fine aggregate with recycled aggregate by (10, 15 and 20%) by volume resulted in decreasing the mechanical properties and increasing the absorption and porosity of RCCP due to the contaminated cement paste on the surface of RCA when compared to the reference mix made with natural aggregate. Because the recycled aggregate contains un-hydrated cement particles, the results have improved after 90 days.

Analyses of the Influence of Service Conditions and Mix Design on the Physical-Mechanical Properties of Roller-Compacted Concrete Pavement

Analyses of the Influence of Service Conditions and Mix Design on the Physical-Mechanical Properties of Roller-Compacted Concrete Pavement

The Compaction of Energy and Properties of Roller-Compacted Concrete Pavement with Fillers

Abstract This case study aims to investigate the effects of compaction methods on the mechanical behavior of roller compacted concrete pavement (RCCP) mixtures, which consist of the replacement of different cement by 0%, 5%, and 10% limestone by volume fraction and which were compacted by two compaction methods. These methods are commonly discussed in the literature and were developed to simulate the site conditions in the laboratory. A modified Proctor test was adopted in the mix’s proportional process to optimize the aggregate’s percentage content of RCCP. The experimental series consisted of compression and split tensile performance tests to investigate the development of compaction performances at 28 days. The results showed that, where 10% of the cement was substituted by limestone, the RCC gives important flexural strength values compared to the quantity of the cement substitute. Qualitatively, the reduction in the strength of the concrete using the modified Proctor compaction method led to the weakness of the bond between the layers.

Assessing flexural and permeability performance of roller-compacted concrete pavement (RCCP) reinforcing with different types of synthetic fibres and crimped steel fibre

ABSTRACT The ever-increasing use of fibres in roller-compacted concrete pavement (RCCP) necessitates fully identifying the mechanical and permeability properties of RCCPs. Incorporating fibres in RCCP with different properties leads to a better comparative investigation that helps discover the unique effects of each fibre on the RCC characteristics. This aim was achieved via analyzing the test results of compressive and flexural strengths, flexural toughness, drying shrinkage, porosity, and water sorptivity. The reinforced RCCs were prepared by incorporating 0.5% and 1% of steel, Barchip, Kortta, and polypropylene fibres in a plain mixture. The plain mixture was chosen between nine mixtures, the differences of which were defined in w/c ratio, volume of cement content, and type of aggregate grading curve. The results indicated that increase in the volume of fibres from 0.5% to 1% could reduce the drying shrinkage rate and enhances the flexural toughness of FR-RCC. Furthermore, the water sorptivity and porosity were found to increase with the substitution of fibres in the RCC mixtures. Here, the water sorptivity of the specimens was highly dependent on the type and surface geometry of fibres. However, apart from other characteristics of fibres, the porosity was significantly increased, using fibres with a high aspect ratio.

Mechanical properties of roller-compacted concrete pavement containing recycled brick aggregates and silica fume

This study looks into the use of waste clay bricks, in roller-compacted concrete pavement (RCCP). To this end, waste were used in RCCP (at 0% to 100%) as a substitute for sand. Silica fume (SF) was also used to enhance the mechanical properties of the concrete. Mix designs containing 5% to 15% of SF were firstly prepared to determine the optimal amount of SF in the RCCP. Then, SF were used in bricks’ combination. Vebe, ultrasonic pulse velocity, compressive strength, water absorption, splitting tensile strength, abrasion resistance, and skid resistance tests were carried out on the samples. The results indicated that up to 25% substitution of brick waste for sand in RCCP did not cause any significant adverse effect. However, in amounts higher than 50%, the properties of concrete were affected. Thus, SF improved concrete properties and is capable of offsetting the negative effects of using bricks waste in RCCP.

Effect of Ground Granulated Blast Furnace Slag (GGBFS) on Mechanical Properties of Roller-Compacted Concrete Pavement

Abstract Because of various convenient features, such as high manufacturing speed, cost effectiveness, and high strength at low ages, roller-compacted concrete (RCC) has found growing use in the construction of concrete pavements. This study investigated the effect of ground granulated blast furnace slag on the mechanical properties (compressive and tensile strength and modulus of rupture) of RCC at the ages of 28 and 90 days. For this purpose, 40 preliminary RCC mix designs based on slag contents of 0, 20, 40, and 60 % (by weight of cementitious materials), moisture contents of 4, 4.75, 5.5, 6.25 and 7 % (by total weight of cementitious materials and aggregates), and cementitious material contents of 12 and 15 % (by weight of aggregate) were devised and tested to determine the optimum moisture content for eight primary mix designs. The primary mix designs were used to make 144 specimens for the evaluation of targeted mechanical properties. The results showed that the moisture content that was needed to reach maximum compaction increased with increasing slag content. The highest strengths were observed in the specimens that contained 40 % slag, which all exhibited equal or greater strength than the corresponding slag-free specimens. The scanning electron microscope images showed that this difference can be attributed to the better filling of pores and cracks with small-sized slag particles, which outperform cement particles in this respect. It seems that there is an optimum level for replacing cement with slag in order to achieve improved strength and that exceeding this level will lead to strength reduction. In this study, this optimum level was found to be 40 % slag. Moreover, increasing the cementitious material content from 12 to 15 % was found to increase the compressive strength, tensile strength, and modulus of rupture by reducing the water-to-cement ratio.

Classification-Based Regression Models for Prediction of the Mechanical Properties of Roller-Compacted Concrete Pavement

In the field of pavement engineering, the determination of the mechanical characteristics is one of the essential processes for reliable material design and highway sustainability. Early determination of the mechanical characteristics of pavement is essential for road and highway construction and maintenance. Tensile strength (TS), compressive strength (CS), and flexural strength (FS) of roller-compacted concrete pavement (RCCP) are crucial characteristics. In this research, the classification-based regression models random forest (RF), M5rule model tree (M5rule), M5prime model tree (M5p), and chi-square automatic interaction detection (CHAID) are used for simulation of the mechanical characteristics of RCCP. A comprehensive and reliable dataset comprising 621, 326, and 290 data records for CS, TS, and FS experimental cases was extracted from several open sources in the literature. The mechanical properties are determined based on influential input combinations that are processed using principle component analysis (PCA). The PCA method specifies that volumetric/weighted content forms of experimental variables (e.g., coarse aggregate, fine aggregate, supplementary cementitious materials, water, and binder) and specimens’ age are the most effective inputs to generate better performance. Several statistical metrics were used to evaluate the proposed classification-based regression models. The RF model revealed an optimistic classification capacity of the CS, TS, and FS prediction of the RCCP in comparison with the CHAID, M5rule, and M5p models. Monte-Carlo simulation was used to verify the results in terms of the uncertainty and sensitivity of variables. Overall, the proposed methodology formed a reliable soft computing model that can be implemented for material engineering, construction, and design.

Properties of roller-compacted concrete pavement containing waste aggregates and nano SiO2

This study deals with the use of waste materials as replacement of fine aggregate in roller-compacted concrete pavement (RCCP). To achieve this, waste ceramic, waste concrete, and waste glass were initially crushed and mixed and then replaced natural fine aggregate at varying amounts in RCCP. Furthermore, to mitigate the probable negative effects of waste aggregates and also to improve the mechanical properties of cement paste, nano SiO2 was employed in the mixes design. After preparing the mixes, Vebe time, compressive strength, splitting tensile strength, water absorption, abrasion resistance, and skid resistance were measured. The results show that more than 40% of sand replacement with waste materials could have a negative effect on the properties of RCCPs. However, this impact is negligible up to 10% of waste material proportions. The compressive strength of the mixes containing waste materials was lower than that of the control mix, except for the sample containing 10% ceramic waste.In terms of water absorption, mixes with waste materials had higher water absorption than the control mix. Besides, abrasion somewhat increased as a result of adding waste materials, except for the samples containing 10% glass and 10% ceramic wastes that showed a slight decrease. Moreover, mixes with waste materials had higher skid resistance than the control mix. Overall, waste ceramic mixes showed better mechanical properties and waste glass mixes had better performance in terms of water absorption. In addition, using nano SiO2 leads to improve the mechanical properties of the RCCP; the optimum content of nano SiO2 has determined to be 0.7% of cement weight.

The effect of using low fines content sand on the fresh and hardened properties of roller-compacted concrete pavement

Aggregate gradation is one of the most important property that influence the behaviour of roller-compacted concrete pavement (RCCP). There are some limitations for gradation of coarse and fine aggregates from the standards. Based on the ACI 211.3R, the content of sand size less than 75 μm should be between 2 to 8% of the total aggregates. To study the effectiveness of using a nonstandard sand (a sand with a gradation out of the specified restrictions) on the properties of RCCP, three types of sand with a difference in very fine particles content were used. The sands used are: 1) standard sand, 2) modified sands containing about 6% limestone powder, and 3) a low fines content sand containing <1% very fine particles. Two types of RCCP containing 12 and 15% cement were used as control mix. The results show that using low fines content sand or limestone modified sand instead of standard sand in RCCP increased Vebe time. The use of low fines content sand in RCCP did not have significant effect on the compressive, splitting tensile and flexural tensile strengths. However, the use of limestone modified sand in the RCCP significantly reduced the mechanical properties. RCCP was made of low fines content sand had more porosity than RCCP with standard sand. It can be concluded from test results that sand with lack in very fine particles can be used in RCCP.

Compressive strength and durability properties of roller-compacted concrete pavement containing electric arc furnace slag aggregate and fly ash

This study investigates the effects of electric arc furnace (EAF) slag aggregate and fly ash on compressive strength and durability properties (i.e. water absorption, abrasion resistance, and sulfate resistance) of roller-compacted concrete pavement (RCCP). The EAF slag aggregate as natural aggregate substitution was used at three levels (i.e. 0%, 50%, and 100%) and cement was replaced by fly ash at three ratios (i.e. 0%, 20%, and 40%). The EAF slag aggregate used in this study was exposed to outdoor condition for several months to reduce the volume instability. The RCCP mixing proportions were determined by soil compaction method. The compressive strength of RCCP was examined at 3-, 7-, 28-, and 91-day age. Meanwhile, the water absorption, abrasion resistance, and sulfate resistance of RCCP at 91-day age were used to study the durability properties. Furthermore, the length change of mortar bars made with EAF slag aggregate was measured to evaluate the expansive potential of EAF slag caused by autoclave condition and alkali-silica reaction (ASR) condition. Additionally, X-ray diffraction analysis was offered to identify the crystalline phases of mortar patterns under autoclave and ASR testing condition. The results presented that the compressive strength and sulfate resistance of RCCP containing EAF slag aggregate declined slightly, whereas the water absorption and abrasion resistance increased in comparison to those of traditional RCCP. Besides, the use of fly ash as cement substitution improved the compressive strength of slag-RCCP at long-term age. A replacement of 20% fly ash provided the slag-RCCP fulfilling the strength and durability requirements for pavement. In addition, the expansion in terms of length change of mortar bars indicated that EAF slag aggregate after the proper treatment performed the volume stability under the autoclave condition and ASR test.

The effect of coarse to fine aggregate ratio on the fresh and hardened properties of roller-compacted concrete pavement

Roller-compacted concrete pavement (RCCP) is an economic and durable rigid pavement. Although about half century has passed since the first RCCP was implemented, information about this type of concrete is still limited. RCCP as a zero-slump concrete, has lower cement content than conventional vibrated concrete. Therefore, the quality of the aggregates has a significant impact on the properties of concrete. For this reason, the quantity of coarse and fine aggregates in RCCP should be optimized. This study investigates the effect of coarse to fine aggregate (C/F) ratio on the fresh and hardened properties of two RCCPs with cement contents of 9% (204 kg/m3) and 12% (268 kg/m3). Compressive strength, splitting tensile strength, flexural tensile strength, Vebe time and porosity tests were carried out. The test results demonstrate that increasing the C/F ratio from 0.6 to 1.8 increased the Vebe time threefold, while increasing the cement content from 9% to 12% decreased the Vebe time by 12%. In addition, increasing the C/F ratio from 0.6 to 1.2 significantly decreased the porosity of RCCP, to about 60% for RCCP with 9% cement and 38% for RCCP with 12% cement. Generally, the most suitable C/F ratio for RCCP appeared to be from 1.2 to 1.4. Thus, to attain a workable, high-strength and durable RCCP, a mix with 12% cement and 1.2C/F ratio is recommended.

Evaluating the effect of macro-synthetic fibre on the mechanical properties of roller-compacted concrete pavement using response surface methodology

This study provides guidance for the design of macro-synthetic reinforced roller-compacted concrete pavement (RCCP) with appropriate consistency and enhanced mechanical performance for pavement applications. The response Surface Methodology was used to study the effects of fibres (0–0.5%), cement (300–350 kg/m3) and water (120–150 kg/m3) on the Vebe time, compressive and flexural strength, and fracture energy of RCCP. The interaction between these three factors were examined modelled using a statistical regression model, showing that the addition of macro-synthetic fibres to the RCCP mixture linearly reduces the RCCP consistency (Vebe time), while fibres do not significantly affect the compressive strength. Based on three-point bending test results on notched beam, fibre, cement, and water linearly affect the flexural strength. However, fibre tended to influence the fracture energy more significantly than flexural strength. It was found that the mortar-fibre interaction highly affects the RCCP post-cracking behavior Therefore, hardening of the post-cracking zone in the load-CMOD curve is expectable for high-flexural strength RCCP at a high volume fraction of fibres.

Shrinkage behaviour of superplasticised RCCP and its relationship with internal temperature

ABSTRACTShrinkage properties of roller-compacted concrete pavement (RCCP) and its relationship with internal temperature variations in superplasticised RCCP were studied. The control and superplasticised RCCPs containing different amounts of sodium naphthalene sulphonate superplasticiser between 1 and 4% by weight of cement were compacted at their optimum water content. The short- and long-term shrinkage and internal temperature variations were monitored in isolated and non-isolated conditions. Micro-structural analysis was implemented using the electron scanning microscope and X-ray diffraction methods. The initial internal temperature of superplasticised RCCP during the first hours of setting was higher than the control mix. A dormant period of low internal temperature was found for superplasticised mixes which started after about 7–13 and 6–10 h in non-isolated and isolated conditions, respectively. For non-isolated condition, the dormant period lasted about 3 days. Under isolated condition, similar trend was found after 4–8 days. During the first day of curing, the total and drying shrinkages of the control RCCP were considerably higher than the superplasticised mixes. On the contrary, the long-term monitoring indicated higher total and drying shrinkages in superplasticised mixes. Based on statistical analysis, the relationship between the autogenous shrinkage and area under the internal temperature diagram was significant.