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This study investigates the feasibility and effectiveness of employing waste ceramic (WC) in rigid pavement as a replacement for fine aggregate. WC was integrated into concrete; untreated and treated with a silane compound, where 30 wt.% and 50 wt.% sand was replaced with WC. The workability, compressive strength, water absorption, skid resistance, microstructural analysis, and surface chemistry of mixtures were evaluated. The results illustrated the positive impact of using treated WC on the water absorption of mixtures, where a maximum reduction of 19% was achieved in the mixture with 50% treated WC. Moreover, concrete with 30% treated WC attained a higher compressive strength of 43 MPa than its untreated counterpart, which achieved 29 MPa, when tested at 28 days. The integration of treated and untreated WC in concrete pavement reduced its skid resistance due to the presence of glaze in the untreated mixture and silane in the treated mixture. The morphological and surface chemistry analyses confirmed the development of C–S–H, CaCO3, and SiO2 in high contents in concrete with silane-treated WC. Also, a strong bonded interfacial transition zone was noticed in concrete with silane-treated WC, unlike concrete with untreated WC, which had a poor interfacial transition zone. [ABSTRACT FROM AUTHOR]

A haunch system improves the performance of a beam-to-column structure, in combination with a geopolymer haunch, the green-concrete concept is supported by reducing the Portland cement use. The energy dissipation, load‒deformation behavior, failure mode, residual deformation, and plastic hinge formation under a loading‒unloading scheme were studied based on experimental full-scale specimens. The responses of the loading‒unloading protocol were compared to the monotonic loading results. A geopolymer and conventional concrete haunch having similar compressive strengths were analyzed. It was shown that the geopolymer haunch performed excellently and that a concrete haunch remarkably improves the performance of a structure regardless of the haunch material. The geopolymer haunch enhanced the load level at first cracking for 10%, and the formation of plastic hinges 0.7% and 4.5% for the monotonic and loading–unloading, respectively, but slightly reduced the ultimate load by 1%. The loading‒unloading protocol had a negative impact of 3% to 7% on the overall performance, the reduction was lower for the geopolymer haunch underlining the superiority of this material. The loading–unloading scheme resulted in a monotonic strength degradation and deviation in failure mode. A finite element model was constructed to generate and analyze the relation of the haunch's concrete strength to the load‒deformation response. It was found that the haunch's compressive strength had no influence on the behavior of the beam-to-column joint, even for a haunch with a compressive strength as low as 25 MPa. [ABSTRACT FROM AUTHOR]

Cement-based materials have low tensile strength and naturel or synthetic-based fibers can be added to the concrete in order to eliminate this adverse effect. In this study, it was aimed to investigate the effects of basalt fiber on the mechanical properties of concrete and the corrosion performance of reinforcement concrete specimens. Control mix, 1, 2, and 3% basalt fiber additive concrete specimens were produced in the study. Concrete specimens were cured in a standard water curing environment for mechanical, physical, and durability tests. Unit weight, ultrasound transition time, splitting-tensile, compression, flexure, electrical resistivity, and rapid chloride permeability tests were performed on concrete specimens. Furthermore, accelerated corrosion and half-cell potential experiments were made on the reinforcement concrete specimens. The changes occurring under the effect of corrosion and the changes in the mechanical and physical properties of the control and basalt fiber concrete series were examined. A significant increase was observed in bending and splitting tensile strengths compared to the reference concrete by using basalt fibers in the concrete mixture. The best results in corrosion tests were seen in 2% basalt fiber reinforced concrete specimens. It has been observed that concretes by using basalt fiber are more resistant to corrosion than control specimens. [ABSTRACT FROM AUTHOR]

The use of waste bricks in pavement construction has gained an immense attraction to researchers because it not only minimizes the scarcity of regular construction materials but also helps in minimizing the waste disposal problems. However, it is sometimes required to add some additives in the mix for improving its strength characteristics, and hence researchers have tried using several additives in concrete/pervious concrete mixes, but the application of nano SiO2 in pervious concrete is a new concept. The prime focus of this study is to check the suitability of using over burnt bricks in the pervious concrete pavement using nano-silica (nano SiO2) as an additive. The laboratory test results show that the addition of nano SiO2 in PC has significantly improved its strength parameters but showed a negative impact on its pore properties. The compressive strength, split tensile strength and flexural strength can be increased by more than 50%, 30% and 55%, respectively, while the porosity and permeability are reduced by around 20% and 45%. Finally, the test results are also validated with the results obtained by other researchers, and it is observed that the PC mixes made with waste over burnt brick aggregates can provide similar results as obtained by using stone aggregates. Although the present study does not incorporate any long-term behaviour of PC, however, from this overall study, it is found that the waste bricks can easily be utilized as a replacement of stone aggregates in the pervious concrete pavement by using nano SiO2 as an additive. [ABSTRACT FROM AUTHOR]

There has been a growing interest in using agricultural waste in concrete construction lately, because of environmental friendliness, resource conservation and economic considerations. Laboratory experiments were conducted to examine the possibility of using palm frond waste ash, as an additive in cement-based composites. The parameters investigated included the effect of palm frond waste ash at 10%, 20%, and 30% admixing levels by weight of cement, on normal consistency and setting times of cement paste, flow, compressive and flexural strength of mortar at 7, 28, 56, and 90 days, and chloride ion permeability of mortar at 28 and 90 days. Similar experiments were also performed on commercially available mineral admixture such as F type fly ash for comparison purposes. Palm frond waste ash additions to portland cement (PC) mortars somewhat increased the water required for normal consistency, prolonged the setting times, marginally lowered the workability, and improved considerably the compressive strength and chloride ion permeability at 28 and 90 days compared to control mixes without ash. Test results indicated that, up to 30% of palm frond waste ash can be added to PC cement mortar without compromising the strength and durability properties and compare fairly well with similar test results reported on a commercial admixture for concrete such as F type fly ash. [ABSTRACT FROM AUTHOR]

Under the traffic action, the pavement crumbling occurs rapidly, which leads to severe impairments that are reflected on the surface layers: rutting, cracking, substances rejection, polishing and pulling out the aggregates on surface. This situation often involves the renovation of the surface's layers. It is, therefore, urgent to appeal to a new vision of pavement design based on optimizing the use of local materials, nonrenewable, and respect for the environment. The recycling of bituminous substances is one of the relevant solutions. It has the advantage of reusing building materials by mixing them with a proportion of refined ones to achieve the required performance. This assignment researches for different rates of coated aggregates, the effects of manufacturing temperature and blending time in the mixing of the constituents during production as well as the additive (powder of rubber) on the improvement of the recycled asphalt rutting. Rutting is one of the most encountered degradation phenomena in the Algerian roads. The formulated hypothesis used here assumes that the additive has an influence on the mechanical performance (rutting) of the recycled asphalt and also on the rate of the used asphalt aggregates. To justify this hypothesis, it is mandatory to go through the manufacture of the asphalt with different rate of asphalt aggregates. To reduce the number of experimental tests necessary for this study, we used the experimental approaches method ANOVA. [ABSTRACT FROM AUTHOR]

Cylindrical concrete reservoirs are appropriate choice to store liquids such as water, oil, ... etc. The use of pre-cast concrete reservoirs considerably increases the speed and precision of construction. In such reservoirs, the assembly of precast wall and roof panels is carried out in construction site. Nevertheless, because of weakness in connections between the wall panels and also between the wall and the foundation, seismic retrofitting may become essential. One innovative method that was applied for seismic retrofitting of numerous precast cylindrical water reservoirs in New Zealand included surrounding the reservoir wall by high tensile post-tensioning cables. In this paper, analytical modeling of wall and roof panels and post-tensioned cables is carried out using the finite element method to investigate the effect of post-tensioning force magnitude, liquid level in reservoir and position of post-tensioning cable on seismic response of reservoir for various height-to-diameter ratios of reservoirs with a constant volume. [ABSTRACT FROM AUTHOR]

The transport of fresh concrete by pumping is an important process and widely used in practical concrete technology. This process has been applied since the beginning of the twentieth century. More recent developments of pumping equipment and findings on mineral and chemical admixtures have prompted more sophisticated research on pumping concretes. While they do not elaborate upon standard specifications, many recommendations for the composition of pumping concretes which are very useful in applications, such as ACI-304.2R reports, are available. This paper reports the results of an experimental study into the effects of concrete components, namely cement content, aggregate type, mineral, fiber, and plasticizer admixtures, on the rheology of pumping concretes. The rheological properties of concretes are examined by the Two Point Workability Test Apparatus (CTPT) originally proposed by G. H. Tattersall. The present study shows that concrete workability is improved by increasing cement content and also shows that the aggregate type only effects the rheological parameters in low cement content mixtures. In addition, yield stress and plastic viscosity are generally lower in concrete mixtures that contain natural stone rather than crushed aggregates. In addition, this study shows that the effect of mineral, plasticizer and fiber admixtures depends on cement content and admixture type. [ABSTRACT FROM AUTHOR]

The article focuses on a study related to examining the bond and compressive strength properties of concrete containing fly ash and silica fume. The concrete mix containing mineral admixtures performed better at high temperatures than the mix without mineral admixtures due to the reaction of the admixtures with free lime, which enhances the strength and durability both at normal and high temperatures.