Fire outbreaks in buildings have been a major concern in the world today. The integrity of concrete is usually questioned due to the fact that after these fire outbreaks the strength of the concrete is reduced considerably. Various methods have been adopted to improve the fire resistance property of concrete. This study focused on the use of coconut fibre to achieve this feat. In this study, varying percentages of treated and untreated coconut fibres were incorporated into concrete and the compressive strength was tested for both before heating and after heating. The percentages of replacement were 0.25, 0.5, 0.75 and 1% fibre content by weight of cement. Concrete cubes that had 0% fibre served as control specimens. After subjecting these concrete cubes to 250 °C and 150 °C for a period of 2 h, the compressive strength increased when compared to the control. The compressive strength increased up to 0.5% replacement by 3.88%. Beyond 0.5% fibre, the compressive strength reduced. Concrete having coconut fibre that had been treated with water also exhibited the highest compressive strength of 28.71 N/mm². It is concluded that coconut fibres are a great material in improving the strength of concrete, even after it was exposed to a certain degree of elevated temperature.

Premature deterioration of our nation’s concrete structures has been a persistent and frustrating problem to those responsible for maintaining them as well as to the public. One of the ways to minimize these problems is to make the concrete less permeable by densifying the cementitious paste. This densification is achieved by using a lower water-cement ratio and supplementary cementitious materials (SCMs). Many researchers have successfully provided a rundown of the current facts about the favorable use of supplementary cementitious materials. These summaries contain a limited number of SCMs considered. This paper reviews the influence of twelve (12) selected supplementary cementitious materials, which are; Cupola Furnace Slag Powder (CFSP), Blast Furnace Slag Powder (BFSP), Silica Fume (SF), Fly Ash (FA), Rice Husk Ash (RHA), Metakaolin (MK), Coconut Husk Ash (CHA), Palm Oil Fuel Ash (POFA), Wood Waste Ash (WWA), Sugar Cane Bagasse Ash (SCBA), Corn Cob Ash (CCA), Bamboo Leaf Ash (BLA), workability and compressive strength of concrete, thus providing a larger database of the current facts about the favorable use of industrial and agricultural byproducts in the concrete industry. Review of literature and careful observation of results were used in generating the useful information provided in this paper. This review considered the compressive strength and workability of concrete containing partial substitute of ordinary Portland cement by the aforementioned supplementary cementitious materials. The chemical compositions of each of these selected supplementary cementitious materials were also reported. This study revealed that the incorporation of these twelve SCMs significantly improves the strength and workability of concrete. It is therefore recommended that arrangements be made by those interested in this paper for processing of these SCMs into commercial cement rather than being disposed of as wastes.

Strength failure persists both in structural and mechanical analysis. One of its prominent characteristics is the adequate provision for parameters that minimise or maximise strength objectives while satisfying boundary conditions. The previous optimisation of concrete strength usually neglects mix design mechanisms induced by optimisation. Recent efforts to accurately optimise the concrete compressive strength have factored in some of these mechanisms. However, optimising concrete strength modified with high silica and alumina precursors, and crucial mix design factors are rare. Consequently, this paper optimised the concrete workability and strength, incorporating binding, water/binder ratio, binder/aggregate ratio, and curing mechanisms using the Box–Behnken design approach (BBDA). A waste material, anacardium occidentale (cashew) nutshell ash, was valorised and used at 5, 10, and 15 wt.% of cement. The composites were made, cured and tested at 14–90 d. The results revealed a high precision between the experimental slump and the optimisation slump at 97% R2. In addition, a 5% increase in compressive strength was obtained compared with the target compressive strength. Besides, the correlation between the model equation obtained from this study and predictions of previous studies via BBDA yielded a strong relationship.

Induction furnace slag (IFS) and quarry dust (QD) were reported as good materials in making ordinary concrete. Studies were not done on utilizing IFS and QD as constituents of high-performance-self-compacting-concrete (HPSCC). This study aims at assessing the effects of induction furnace slag and quarry dust on the strength and durability of high-performance self-compacting concrete. Strength tests including compressive, flexural, split tensile, rebound hammer tests were conducted on HPSCC. Likewise, durability tests including water absorption, total porosity and electrical resistivity tests were conducted. IFS at 0 % to 50 % (at 10 % intervals) replacement with Portland cement was used. Also, the optimum IFS content was combined with QD at 0 % to 50 % (at 10 % intervals) replacement with river sand. The results revealed an increment in strength up to 20 % IFS, 50 % QD with a rise of 15.34 % compressive strength over the control. The durability improved up to 20 % IFS, 60 % QD with a rise of 16.86 % electrical resistivity over the control. These showed that IFS and QD can be used for the production of HPSCC.

The brittle nature of concrete has always necessitated the need for various forms of reinforcement that will absorb the tensile stress that is responsible for cracking. Conventionally, steel rebar embedded in concrete, giving rise to reinforced concrete structures has turned out to be a composite material that has been most used for infrastructural development around the world. The ductility impacted on concrete by steel rebar has been very efficient, though reinforced concrete structures are prone to durability challenges when exposed to adverse environmental conditions. Most times, repairing deficient concrete structures is more economical and sustainable than total replacement. Various approaches have been successfully implemented around the world in strengthening weakening reinforced concrete structures, nevertheless, bonding of fiber reinforced polymer (FRP) composites to the soffit of weak beams is turning out to be a viable option. Of particular interest is the adoption of naturally occurring fibers for laminates used for beam strengthening. In this era of Sustainable Development Goals (SDGs), in which the world is striving to reduce the effects industrial productions on the environment, advances in adopting renewable materials is highly welcomed. This research reviews the past works on the use of natural fibre-based composites in strengthening deficient reinforced concrete beams. The outcome of this research will go a long way in contributing towards the achievement of the SDGs.