The micro-cracks in concrete structures are inevitable due to deterioration throughout their service life through various load combination factors. For that reason, there is a need to repair and maintain the concrete in order to prevent the cracks from propagating, which can decrease the service life of the structure. Using bacteria is one of the possible solutions to repair and heal the cracks. Recent research has shown that, in order to achieve the extended service life of a concrete material, a bio-influenced material, such as bacteria, can be used in order to induce the autonomous self-healing of cracks in concrete. Many researchers are still exploring the potential of bacteria for improving the durability and strength of concrete. However, an inclusive literature review revealed that a self-healing mechanism using bacteria can still be improved. There is an imperative need to conduct a comprehensive review about the recent development of and studies into the self-healing mechanism of concrete, in particular with the behavior of bacteria and its effect on the macro, micro and nanostructure of the concrete matrix. This review article can reveal the potential research gap, predict the emerging research topics and define all existing problems or challenges about the bio-influenced self-healing mechanism in concrete. The latest articles are summarized and analyzed using the Latent Dirichlet Allocation (LDA) in Matlab software in order to come up with a possible area of development and future research into bio-concrete. Microencapsulated technology and acoustic emission could be the emerging methods for evaluating the performance of the bacteria and detecting real time cracks inside the concrete matrix in the future. However, there are still existing problems and challenges regarding the adoption of bacteria in the field of construction industry.

This study explored self-healing in geopolymer mortar cured at ambient temperature using polypropylene fibers and bacterial co-cultures of Bacillus subtilis and Bacillus megaterium. Damage degree, compressive strength, ultrasonic pulse velocity (UPV), strength-regain percentage, and self-healing percentage were evaluated. A full factorial design was used, which resulted in an eight-run complete factorial design with four levels in the first factor (polypropylene content: 0%, 0.25%, 0.5%, and 0.75%) and two levels in the second factor (bacteria concentration: 0 (without) and 1 (with)). The results indicate that increasing the polypropylene fiber content enhanced strength regains up to 199.97% with 0.75% fibers and bacteria. The bacteria alone improved strength-regain percentages by 11.22% through mineral precipitation. The analysis of variance (ANOVA) showed no interaction between fibers and bacteria, but both independently improved the compressive strength. Only bacterial samples exhibited positive self-healing, ranging from 16.77 to 147.18%. The analysis using a scanning electron microscope with energy dispersive X-ray (SEM-EDX) and X-ray fluorescence (XRF) also revealed greater calcite crystal formation in bacterial samples, increasing the strength-regain and self-healing percentages. The results demonstrate that polypropylene fibers and bacteria cultures could substantially enhance the strength, durability, and self-healing percentage of geopolymer mortars. The findings present the potential of a bio-based self-healing approach for sustainable construction and repair materials.

This paper provides information on the effects of organoclay (OC) impregnation in the thermal, physical and mechanical properties of recycled composite materials. The raw material was a flexible industry trimmings from a food packaging manufacturing plant. Various material testing standards were employed to determine the properties of the recycled materials. Results showed that the recycled material has significant effect in retarding the linear rate of burning due to the yielded ρ – value equal to zero (0). The resistance factors showed that the recycled material is potential as insulation, barrier, or roofing tile. These information is an indication that impregnation of OC enhanced the recycled material to be thermal resistant, gas and water vapor barrier and as potential barrier material.

Vibration is one of the main factors for fatigue in structures which can cause damages such as cracks and in critical cases could result to collapse. Long term contact to vibrations can induce the cracks to be transmitted through the structural members of the building that can compromise the structural integrity of the structure. The Ozanam Building of Adamson University is situated near the Romualdez Street, which is considered as one of the main routes of cargo trucks and other heavy vehicles from the Manila North Harbor Port. It was observed that cracks were visible on the façade of the building. For that reason, the structural integrity of Ozanam Building was evaluated against the traffic-induced vibrations using vibration meter. It was found out that the maximum peak particle velocity present in Ozanam Building is 8.60 mm/s which means that the building is safe and below the threshold value for risk in structural damage. Thus, vibration due to traffic has no significant effect that can cause structural damage to the building. In addition, preventive measures were discussed in this paper to reduce the traffic-induced vibrations to an acceptable level.