The use of natural fibers in cementitious composites continue gaining acceptability and applicability due to the shortcomings and disadvantages of synthetic fiber; this is because natural fibers have advantages of sustainability, eco-friendliness, and economy. Biodegradable natural fibers, being low density and lightweight, with typical values of strength-to-weight ratio, aspect ratio, elastic modulus, and strength, may be competitive for substituting synthetic fibers such as glass and carbon. Indeed, natural fibers are mostly non-irritating for the skin and typically pose no troubles or issues for breathing, which is not the case with many synthetic fibers. Date palm fiber (DPF) is a natural fiber obtained as waste material from a date palm tree. In many countries, with large date production, DPF is easily available as a process by-product, with a low processing cost. Being sustainable and environmentally friendly, DPF is continuously gaining acceptability as fiber material in different composites such as concrete, mortar, gypsum composites, clay composites, and bricks. Based on the most available literature reviewed, DPF reinforced composites have been found to be a good insulation material, with higher thermal properties, thereby reducing energy consumption which consequently saves the running and maintenance cost of the building. DPF reinforced composites were reported to have higher energy absorption capacity, ductility, and bending resistance, leading to delaying crack propagation and preventing catastrophic failures of structures such as beams and slabs. Additionally, due to its lower density, DPF reinforced composites have the advantage for usage in areas prone to seismic effects, and when used for buildings, the overall weight of the building is expected to reduce hence reduction in foundation cost. The major setback of using DPF in composites is the reduction in the compressive strength of the composites and the durability performance of the composites. Therefore, for effective usage of DPF in composites to derive the maximum benefits, there is a need to devise a method of mitigating its negative effects on the compressive strength and durability performance of the Composites; this is a future study that needs to be explored for better performance of DPF in cementitious and other materials composites.

The construction industry has been dealing with numerous issues in order to achieve the projects’ objectives. Hence, caused most projects to suffer low performance, particularly in terms of cost and time overrun and poor quality level. Regarding this matter, the last decade has shown a frequent failure of projects which clearly describes the need for a systematic investigation of the coordination process effects on the performance of the project. The study investigates the impression of coordination factors on projects performance by adopting structural equation modeling (SEM) technique via fit indices and standardised paths. In current research case data were obtained from a questionnaire distributed among owners/developers, contractors, and consultants. A theoretical structural equation model was developed to signify the effect of five main latent variables on project performance. The outcomes showed that projects with high performance have better coordination efficiency. Whereas, planning and scheduling factors (PSF) group is the highest significant group that had a great influence on performance, while records and documentation factors (RDF) group obtained the second important score. Overall, the outcome of this study is expected to contribute to the construction management efforts, particularly in addressing the root causes of poor performance and improving projects success.

The use of date palm fiber (DPF) as natural fiber in concrete and mortar continues to gain acceptability due to its low-cost and availability. However, the main disadvantage of DPF in cement-based composites is that it reduces compressive strength and increases the porosity of the composite. Hence, for DPF to be efficiently used in concrete, its negative effects must be counteracted. Therefore, in this study, silica fume was employed as supplementary cementitious material to alleviate the negative effects of DPF on the strength and porosity of concrete. The DPF was added in different dosages of 0%, 1%, 2%, and 3% by weight of binder materials. Silica fume was used as a cement replacement material at dosages of 0% to 15% (intervals of 5%) by volume of cement. The unit weights, mechanical strengths, water absorption, and microstructural morphology were all evaluated. The concrete’s fresh and hardened densities were reduced with the increment in DPF and silica fume. The compressive strength declined at all ages with the increment in DPF addition, while the flexural and splitting tensile strengths improved with addition of up to 2% DPF. Furthermore, the concrete’s water absorption escalated with an increase in DPF content. Silica fume significantly enhanced the mechanical strength of the concrete. The dissipation in compressive strength with the addition of up to 2% DPF was mitigated by replacing up to 10% cement with silica fume, where it densified the microstructure and refined the interfacial transition zone between the fibers and cement matrix, hence significantly decreasing the porosity and enhancing durability.

Calcium carbide residue (CCR) is the end-product of production of acetylene gas for the applications such as welding, lighting, ripening of fruits, and cutting of metals. Due to its high pH value, disposing of CCR as a landfill increases the alkalinity of the environment. Therefore, due to its high calcium content, CCR is mostly blended with other pozzolanic materials, together with activators as binders in the cement matrix. In this study, cement was partially substituted using CCR at 0%, 7.5%, 15%, 22.5% and 30% by weight replacement, and nano silica (NS) was utilized as an additive by weight of binder materials at 0%, 1%, 2%, 3% and 4%. The properties considered were the slump, the compressive strength, the flexural strength, the splitting tensile strength, the modulus of elasticity, and the water absorption capacity. The microstructural properties of the concrete were also examined through FESEM and XRD analysis. The results showed that both CCR and NS increase the concrete’s water demand, hence reducing its workability. Mixes containing up to 15% CCR only showed improved mechanical properties. The combination of CCR and NS significantly improved the mechanical properties and decreased the concrete’s water absorption through improved pozzolanic reactivity as verified by the FESEM and XRD results. Furthermore, the microstructure of the concrete was explored, and the pores were refined by the pozzolanic reaction products. The optimum mix combination was obtained by replacing 15% cement using CCR and the addition of 2% NS by weight of cementitious materials. Therefore, using a hybrid of CCR and NS in concrete will result in reduction of cement utilization in concrete, leading to improved environmental sustainability and economy.

Waste tire disposal continues to pose a threat to the environment due to its non-biodegradable nature. Therefore, some means of managing waste tires include grinding them to crumb rubber (CR) sizes and using them as a partial replacement to fine aggregate in concrete. However, the use of CR has a series of advantages, but its major disadvantage is strength reduction. This leads to the utilization of calcium carbide waste (CCW) to mitigate the negative effect of CR in self-compacting concrete (SCC). This study investigates the durability properties of SCC containing CR modified using fly ash and CCW. The durability properties considered are water absorption, acid attack, salt resistance, and elevated temperature of the mixes. The experiment was conducted for mixes with no-fly ash content and their replica mixes containing fly ash to replace 40% of the cement. In the mixes, CR was used to partially replace fine aggregate in proportions of 0%, 10%, and 20% by volume, and CCW was used as a partial replacement to cement at 0%, 5%, and 10% by volume. The results indicate that the mixes containing fly ash had higher resistance to acid (H₂SO₄) and salt (MgSO₄), with up to 23% resistance observed when compared to the mix containing no fly ash. In addition, resistance to acid attack decreased with the increase in the replacement of fine aggregate with CR. The same principle applied to the salt attack scenario, although the rate was more rapid with the acid than the salt. The results obtained from heating indicate that the weight loss was reduced slightly with the increase in CCW, and was increased with the increase in CR and temperature. Similarly, the compressive strength was observed to slightly increase at room temperature (27 °C) and the greatest loss in compressive strength was observed between the temperature of 300 and 400 °C. However, highest water absorption, of 2.83%, was observed in the mix containing 20% CR, and 0% CCW, while the lowest water absorption, of 1.68%, was found in the mix with 0% CR, 40% fly ash, and 10% CCW. In conclusion, fly ash is recommended for concrete structures immersed in water, acid, or salt in sulphate- and magnesium-prone areas; conversely, fly ash and CR reduce the resistance of SCC to heat beyond 200 °C.