A review of utilization of industrial waste materials as cement replacement in pervious concrete: An alternative approach to sustainable pervious concrete production

Around 8% of the global carbon dioxide emissions, are generated during cement manufacturing, which also involves significant use of raw materials, leading to adverse environmental effects. Consequently, extensive research is being conducted worldwide to explore the feasibility of utilizing different industrial waste by-products as alternatives to cement in concrete production. Fly ash (FA), Metakaolin (MK), Silica fume (SF), and ground granulated blast furnace slag (GGBS) are potential industrial materials that can serve as cement substitutes in pervious concrete. However, there exist conflicting findings in the literature regarding the impact of industrial supplementary cementitious materials (ISCMs) as partial cement replacements on the physical, mechanical, and durability properties of pervious concrete. The aim of this review is to investigate the feasibility and potential benefits of using ISCMs and compare them as partial cement replacements in the production of pervious concrete. The analysis primarily examines the effect of ISCMs as partial cement replacements on cementitious properties, including properties of ISMCs, mechanical properties, and durability of pervious concrete. The influence of ISCMs primarily stems from their pozzolanic reaction and filler characteristics. SF has the highest reactivity due to its high surface area and amorphous structure, resulting in a rapid pozzolanic reaction. GGBS and FA have moderate reactivity, while MK has relatively low reactivity due to its crystalline structure. Results from various studies indicate that the addition of FA, SF, and MK up to approximately 20% leads to a reduction in porosity and permeability while improving compressive strength and durability due to the filler effect of SF and MK. Incorporating GGBS increases permeability slightly while causing a slight decrease in compressive strength. The range of permeability and compressive strength for pervious concrete incorporating FA, SF, GGBS and MK were 0.17–1.46 cm/s and 4–35 MPa, 0.56–2.28 cm/s and 3.1–35 MPa, 0.19–0.64 cm/s and 8–42 MPa, 0.10–1.28 cm/s and 5.5–41 MPa, respectively, which are in the acceptable range for non-structural application of pervious concrete. In conclusion, it is possible to produce sustainable pervious concrete by substituting up to 20% of cement with FA, SF, GGBS, and MK, thereby reducing cement consumption, carbon footprint, energy usage, and air pollution associated with conventional cement production. However, further research is required to systematically assess the durability properties, long-term behavior, and, develop models for analyzing CO2 emissions and cost considerations of pervious concrete containing ISMCs

Determining the causes of delay by using factor analysis in Tehran’s construction projects

Construction industry is one of the most profitable sectors in Iran’s economic. Delay is common problem in the construction projects in Iran. By considering all viewpoints of the parties, this research identified the most effective and severe causes of delay in construction projects in the Capital of Iran, Tehran. Questionnaires were distributed among respondents who are involved in the construction project in Tehran. The process of data analysis and discussions were conducted based on the two statistical techniques namely descriptive analysis (RII) and factor analysis. Using factor analysis, most critical factors of Tehran’s construction delay were recognized as: (1) lack of commitment; (2) inefficient site management; (3) poor site coordination; (4) Complexity in heritage and legislation; (5) Lack of estimation skills and skilled workers; (6) Lack of communication between parties; (7) Improper planning; and (8) Lack of clarity in contract. These results are anticipated to be important contributions to construction projects in Tehran in controlling the time overruns in construction contracts

Sustainable clean pervious concrete pavement production incorporating palm oil fuel ash as cement replacement

The significant increase in global urban population and rapid growth of impervious urban surfaces result in erosion of stream channels, flooding, and damage to stormwater infrastructures. The aim of this research was to study pervious concrete pavement as a sustainable solution to control the stormwater at source, reducing heat island effect and enhancing safety of driving. The sustainability of pervious concrete can be increased and the carbon dioxide emissions reduced by replacing a huge amount of ordinary Portland cement with waste materials such as palm oil fuel ash. Palm oil fuel ash is a waste material obtained from the combustion of oil palm shells and fibers in palm oil industry to produce electricity, which caused environmental problems in countries such as Indonesia and Malaysia. This study presented experimental investigations to assess the substitution of control pervious concrete with palm oil fuel ash up to 40% (by mass) to produce sustainable and eco-friendly pervious concrete pavement. Density and void content of specimens were determined at fresh and hardened-state. Falling head permeability test was carried out to investigate the stormwater filtration capacity. Compressive and tensile strengths were conducted on pervious concrete specimens. Skid and abrasion resistances were also employed to evaluate the effects of palm oil fuel ash on safety of driving and surface durability of the pervious concrete pavement. The results showed that void content and water permeability of pervious concrete increased slightly with increasing palm oil fuel ash, while compressive and tensile strengths decreased. They satisfy the typical range for pervious concrete according to American Concrete Institute. A minor effect of palm oil fuel ash on the skid resistance was observed, increasing its substitution levels caused the abrasion resistance of pervious concrete mixtures to decrease. The heavy metal concentrations in leachates of the pervious concrete containing 40% palm oil fuel ash were significantly lower than recommended in the standard. The pervious concrete containing 20% palm oil fuel ash presented the most optimum mixture both technically and environmentally

Performances and properties of steel and composite prestressed tendons – A review

The primary drawback of concrete lies in its low tensile strength, prompting the development of various solutions to enhance this aspect. A notable approach is the utilization of Prestressed Reinforced Concrete (PRC) with tendons, aimed at bolstering its tensile strength. As the use of diverse tendon types in the PRC continues to surge, a review becomes imperative to delve into this evolution. Therefore, this study delved into the engineering characteristics, performance, and evolution of different tendon varieties, encompassing both steel and composite options. Despite certain drawbacks associated with employing composite materials such as Fiber Reinforced Polymer (FRP) tendons - such as heightened costs, limited availability of composite materials, and intricate manufacturing processes - there are distinct advantages and merits to incorporating FRP composite tendons in the realm of construction. In this respect, Carbon FRP tendons exhibited superior strength, comparable to their steel counterparts. Glass FRP tendons, lacking metallic components, possessed non-magnetic properties, rendering them resistant to corrosion. Additionally, Aramid FRP tendons boasted low flammability and exceptional resistance to elevated temperatures. Lastly, Basalt FRP tendons offered sustainability, rust resistance, and non-corrosiveness. The findings derived from this review study serve as a valuable resource for researchers seeking to advance the applications of steel tendons and FRP composite materials within the construction industry

On blended cement and geopolymer concretes containing palm oil fuel ash

This article discusses the utilization of palm oil fuel ash (POFA) in normal and geopolymer concrete. Malaysia, one of the world's largest producers of palm oil, produces more than 10Mt/year of palm waste as ash, which is called POFA. Since 1989, extensive research has been conducted on its utilization in concrete. Several published studies have noted POFA's enormous potential as a partial replacement of cement in concrete. This paper describes the effects of using POFA on different fresh and hardened properties of concrete. The latest studies on the use of ground POFA revealed that concrete made from this material possesses better fresh properties and medium to higher strength than ordinary Portland cement (OPC) concrete. One of the major findings is that concrete that incorporates 20% fine POFA by weight of cement showed better durability properties than OPC concrete. Because limiting CO2 emissions has become a matter of increasing importance in the construction industry, concrete that uses less cement in its production and utilizes an increased amount of waste, such as POFA, offers an environmentally viable solution. Moreover, 100% cement-free geopolymer concrete can be produced using blended ash, such as POFA and fly ash