The Effect of the Utilization of Sustainable Materials on Some Mechanical Properties of Geopolymer Mortar

Recycling and sustainability are important topics nowadays due to the increased environmental problems and waste accumulation. In this research, focus was given on the production of sustainable pervious concrete. Four mixes were prepared: a reference mixture, a mixture with 30% of the volume of coarse aggregates replaced with ceramic waste, the third mixture was similar to the second, but it contained 10% metakaolin instead of cement, and the fourth mixture was similar to the third, but carbon fibers were added. Thermal conductivity and density tests were carried out after 28 days of curing on the casting samples, while flexural tests were performed after 7 and 28 days. The results showed that flexural strength, density, and thermal conductivity were decreased in the second and third mixtures compared to the reference mixture, but in different decreasing percentages, so the good effect of metakaolin became clear. The addition of carbon fibers to the fourth mixture led to an increase in flexural strength and thermal conductivity, whereas density was lower than in the reference and third mixtures.

Effect of Sustainable Materials on Some Properties of Pervious Concrete

Kazem,

Fawzi

2024

Behavior of Modified Reactive Powder Concrete Containing Sustainable Materials and Reinforced with Micro-Steel Fibers

Saeed,

Fawzi

2024

Reusing and recycling construction debris offers intriguing opportunities for resource conservation and waste disposal site economies. This study investigates the feasibility of using 10 mm crushed brick as coarse aggregate in Modified Reactive Powder Concrete. Natural sand was substituted with crushed brick aggregate by 25, 50, and 100%. Up to 7 and 28 days of age, the tensile strength, absorption, and void content of the mixtures were compared with those of a mixture without coarse aggregate. According to the test results, it is feasible to produce Modified Reactive Powder Concrete (MRPC) with coarse aggregate or shattered bricks. Compared to the reference mixture, the tensile strength of MRPC decreased as the replacement ratio of broken bricks increased. At 7 and 28 days of testing, the tensile strength increased by 10.2 and 12.06 with 25% crushed bricks compared to normal reactive powder concrete. Tensile strength decreased by 7.2% and 6.27% at 7 days and by 9.89% and 8.87% at 28 days when replacing fine sand with crushed brick aggregate at rates of 50% and 100%, respectively. Compared to the reference mixture, the absorption and void content of MRPC with 25, 50, and 100% crushed brick increased by 13.6, 61.2, and 116% and 15.9, 62.1, and 136%, respectively.

Evaluation of the Enhancement of the Mechanical Properties of Cement Mortar Incorporated with Porcelain and Marble Powder

Hussain,

Fakri Jawad,

Obais

et al. 2024

It is widely accepted that cement and concrete are substantial sources of CO2 emissions. Researchers have been looking to replace cement with industrial waste to reduce the environmental impact of concrete production. The current research focuses on successfully using marble powder (M) and porcelain powder (P) instead of cement to produce cement mortar. Both mechanical and microstructural characteristics of several single and binary mixtures consisting of M and P were examined, with 13 mixes with M and P having been replaced by 2.5, 5, 7.5, and 10% of cement weight. For all mixtures in this work, compressive strength, flexural strength, SEM analysis, and thermogravimetric analysis (TG/DTA) were applied. The mixtures containing 10% M, 10% P, and 5% M+5% P demonstrated the best results. The maximum values recorded in compressive strength were 52, 55, and 50 MPa, whereas the control mix had 30 MPa. The maximum values for flexural strength were 9.24, 10.64, and 8.4 MPa in comparison with the 7 MPa of the control mix. Moreover, SEM analysis demonstrated the existence of a thick and compacted microstructure, which is predominantly the result of the formation of both Calcium Hydroxide (C-H) and high-density Calcium Silicate Hydrate (C-S-H) phases in all blends. SEM images demonstrated how hydration compounds formed and how the presence of M and P improved bonding. The difference in the quantities and types of phases distinguished by the different types of substitute material was also noted. The decrease in C-H, which is most prominent after a hydration period of 28 days, is primarily attributed to the interaction between C-H and M and P. Thus, this study demonstrates that M and P, by themselves or in combination, can be utilized as alternative resources in the production of high-performance and sustainable concretes.