Economic advantages and rapid construction of Roller compacted concrete (RCC) has been considered by researchers and stakeholders of hydraulic structures with the increasing use of Roller compacted concrete in dams industry and highway projects. The purpose of this experimental research is to investigate the influence of polypropylene fibers with different size and amounts on the mechanical properties of Roller compacted concrete. Different type of fibers and admixtures has been suggested and in this research, cement type II from Sofian cement factory, silica fume from Azna-Lorestan factory, super plasticizer with poly carboxylic base, aggregates from Talmase factory (coarse aggregate with Dmax= 50 mm and fine aggregate with FM= 3.12), filler from Azardash factory, and poly-propylene fibers from Isfahan factory in different sizes of 6 and 12 mm by using in amounts of 0.35, 0.70 and 1.4 kg/m3. Cylindrical samples of 150´300 mm were prepared with above mentioned local materials and cured in fresh water in definite periods days of 3, 7 and 28 days in laboratory temperature and tested according to standards ASTM C39 and ASTM C496 for compressive and tensile strengths of samples. Consideration of test results showed that the Aspect Ratio of fibers is an important factor in strength of samples. Mainly for compressive strength, the best results come out by shorter fibers; and for tensile strength, the best results were with longer fibers. According to the test results, using polypropylene fibers in Roller compacted concrete mix, tensile strength was increased almost 20%.

This research aimed to investigate the mechanical and physical properties of Roller compacted concrete (RCC) used with Recycled concrete Aggregate (RCA) as a replacement for natural coarse aggregate. The maximum dry density method was adopted to prepare RCC mixtures with 200 kg/m³,of cement content and coarse natural aggregates in the concrete mixture. Four RCC mixtures were produced from different RCA incorporation ratios (0%, 5%, 15%, and 30%). The compaction test, compressive strength, splitting tensile strength, flexural tensile strength, and modulus of elasticity, porosity, density, and water absorption tests were performed to analyze the mechanical and physical properties of the mixtures. One-way Analysis of Variance (ANOVA) was used to identify the influences of RCA on RCC’, s mechanical properties. As RCA increased in mixtures, some mechanical properties were observed to decrease, such as modulus of elasticity, but the same was not observed in the splitting tensile strength. All RCCs displayed compressive strength greater than 15. 0 MPa at 28 days, splitting tensile strength above 1. 9 MPa, flexural tensile strength above 2. 9 MPa, and modulus of elasticity above 19. 0 GPa. According to Brazilian standards, the RCA added to RCC could be used for base layers.

In this study، some mechanical properties of Roller compacted concrete (RCC) containing recycled concrete aggregate (RCA) have been investigated. Different mixtures of RCC، in which the fine، coarse or fine and coarse fractions have been replaced with RCA have been made and their mechanical properties including compressive strength، flexural strength، elastic modulus and energy absorption have been evaluated. The compressive and flexural strength of the mixtures have been measured at the different curing ages of 7، 28 and 91 days، while the elastic modulus and energy absorption have been evaluated on the specimens cured for 28 days. Results show that the mixtures containing RCA have a slightly less compressive strength than the control mixture made of natural aggregate. The highest compressive strength was obtained for the mixture containing recycled coarse fraction and natural fines. The flexural strength test results showed that the mixtures containing recycled aggregates have a higher flexural strength than the control mixture، with the highest flexural strength for the mixture containing coarse RCA and natural fines. Furthermore، the ratio of flexural to compressive strength، which is used as an indicative of energy absorption، is higher for the mixtures made of RCA، with the highest for the mixture containing both fine and coarse RCA. The elastic modulus test results show that the mixtures containing RCA have a higher energy absorption than the control mixture، while their elastic modulus is less than the that of the control mixture. The lowest elastic modulus was obtained for the mixture containing both coarse and fine fraction of RCA. This research results show that RCA obtained from structural concrete is feasible to be used in RCC.

In recent years, the asphalt production cost has been increased appreciably. On the other hand, by decreasing the construction projects, the cement industries could not work at full capacity. In order to overcome these problems a considerable attention has been attracted to the development of concrete pavements. This study was thus conducted to investigate the durability and mechanical characteristics of Roller compacted concrete Pavements (RCCP).The influence of variation in water content was investigated by using different w/c of 0.33, 0.35 and 0.38. Three different cement contents of 325 kg=m3, 350 kg=m3, and 375 kg=m3 were also made for comparison purposes. A pozzolanic cement concrete and a concrete mixture with 7% cement replaced by silica fume were also compared to the plain concrete.The concrete mixtures had 28 days compressive strengths higher than 35 MPa, surpassing the recommended minimum level of ACI325-10R. Increasing the cement content, in conjunction with decreasing w/c content, led to higher compressive strengths at 7 and 28 days. Silica fume concrete outperformed the other mixtures at 28days. Similar trends were obtained for flexural strength test results.The durability results indicate that by decreasing the w/c content from 0.33 to 0.38, the penetration depth of water was reduced from 10 mm to 14 mm. The lowest penetration depth was observed for the mixtures containing silica fume and the pozzolanic cement. This shows a more tortuous and discontinuous microstructure in these mixtures due to pozzolanic reactions.The salt scaling resistance results indicate that the mixture containing silica fume had higher deicer salt scaling resistance compared to the other mixtures. The mixtures with pozzolanic cement and that with the lowest w/c content (0.33) had also higher resistance against salt scaling compared to the other plain mixtures. Increasing the w/c content significantly influence the salt scaling resistance of the mixtures, leading to lower salt scaling resistance.

This study implemented the artificial bee colony (ABC) metaheuristic algorithm to optimize the Artificial Neural Network (ANN) values for improving the accuracy of model and evaluate the developed model. Compressive strength of RCC was investigated using mix design materials in three forms, namely volumetric weight input (cement, water, coarse aggregate, fine aggregate, and binder), value ratio (water to cement ratio, water to binder ratio, and coarse aggregate to fine aggregate ratio), as well as the percentage of mix design values of different ages. A comprehensive, proper-range dataset containing 333 mix designs was collected from various papers. The accuracy of the research models was investigated using error indices, namely correlation coefficient, root-mean-square-error (RMSE), mean absolute error (MAE), and developed hybrid models were compared. External validation and Monte Carlo simulation (MCS)-based uncertainty analysis was also used to validate the models and their results were reported. The experimental stage of the prediction of compressive strength values showed significant accuracy of the ANN-ABC model with (MAE=11.49, RMSE=0.920, RME=5.21) compared to other models in this study. Besides, the sensitivity analysis of predictor variables in this study revealed that the variables “specimen age,” “binder,” and “fine aggregate” were more effective and important in this research. Comparison of the results showed that the improved proposed model using the ABC algorithm was more capable and more accurate in reducing the error rate in providing computational relations compared to the default models examined in the prediction of the compressive strength of RCC and also tried in simplifying computational relations.

Roller-compacted concrete (RCCP) is a zero-slump and stiff-dry mixture which is usually placed with an asphalt paver and compacted by conventional vibratory Roller compactors to achieve the required density. Typically, the RCCP is constructed without joint. It needs neither forms nor surface finishing, nor does it contain bar reinforcing and dowels. Consequently, considering a proper mix design, load transfer can be achieved through aggregate interlock. Nevertheless, RCCP can be reinforced with fibers in order to improve the durability, flexural strength, load transfer capacity, and so on. Accordingly, this research was conducted to study the effects of fibers on the mechanical properties of RCCP and present a prediction fatigue model based on third-point beam fatigue test. Based on three-point bending test results on notched beam, fiber, cement, and water linearly affect the flexural strength. However, fiber tended to influence the fracture energy more significantly than flexural strength. It was found that stress ratio, fiber content and fracture energy was the significant term to predict fatigue life, respectively.

Highway construction industry produces millions of tons of recycled asphalt annually, large amounts of which usually remain unusable and occupy the stockpile areas. Therefore, the suitable use of these materials is inevitable. Although, using of recycled asphalt pavements (RAP) in asphalt mixtures is common, there are few consideration about using of these materials in Portland cement concrete especially Roller compacted concrete. In this study, RAP materials were used as coarse aggregates, fine aggregates, and both fine and coarse aggregates in the Roller compact concrete mixes. The energy absorbency of specimens were analyzed with the force-deformation curves that obtained from the three-point flexural test. Results revealed the beneficial effects of the RAP material on the energy absorbency or material flexibility. Based on the laboratory results, replacing the coarse part with RAP will achieve an intermediate mixture which exhibited higher flexibility than the reference specimen and higher strength than two other mixes which containing fine RAP and both parts of RAP.

Construction of dams by using Roller compacted concrete (RCC) is a relatively recent technology which has increasingly developed in the past few years. With regard to various horizontal lift joint in the body of RCC dams and in order to increase the safety factor in the design, the experimental investigation was conducted on the basis of improving bond strength in RCC by using interface cement grout and imparting changes in normal pressure. RCC samples were constructed in two layers with maximum aggregate size of 25 mm, type I cement of Isfahan plant and Khash pozzulan. On the whole, in different conditions of using grout with w/c ratio of 0.5, 0.75, and 1 as well as no grout condition, the first stage of bond strength tests in normal pressure (0, 5, 10, and 15 kg/cm2) by using the designed machine in this study and the second stage tests were conducted in normal pressure (20, 25, 30, 35, and 40 kg/cm2) by using stone direct shear machine. From the sum of 250 made samples, the results of bond strength and compressive strength in 7, 28, and 90 days in the first stage, and the results of maximum bond strength and residual bond strength in 28 days in second stage have been obtained. On the basis of the results obtained, bond strength parameters have been obtained and analyzed. The results of this study indicated that the Mohr coulomb criterion shows the upward tend of bond strength with an increase in normal pressure very well, and by increasing the normal pressure from the first stage to the second stage, interface cohesion decreases and the interface angle increases. Also, by using grout between layers paves, the way for an increase in bond strength compared to the no grout condition, and there will be a decrease in bond strength with an increase in w/c ratio of grout. In this case, changes in cohesion parameter are in phase with changes in bond strength while to sensible changes in interface conditions are evident on the interface friction angle.

Roller compacted concrete (RCC) is a type of zero slump concrete produced from the same materials with normal concrete. Use of RCC has substantially increased in the last decades especially for pavement applications. It has a low construction cost and can be done quickly compared to asphalt pavement. It is widely constructed in roads carrying heavy loads in low speed. Also in recent years, the use of RCC in highways and inner-city streets has also increased. Roller compacted concrete pavement (RCCP) has a competitive advantage over high-performance asphalt pavements in terms of high compressive strength, good durability, low maintenance cost and longer service life. In this article at first, the materials used in the production of RCC, including cement, stone materials, water, and finally the method of mixing plan are discussed. Then to examine the properties of RCC with a focus on RCCP including mechanical properties, modulus of elasticity, fatigue and creep behavior, volume change, thermal properties, permeability and water absorption, wear, durability of pavement in the cycle of melting and freezing and surface properties of RCC been paid. The purpose of this article is to know the different characteristics of RCC and the research done in the mixture design to achieve a mixture with greater strength and durability.