Durability Performance of Self-Compacting Concrete Containing Crumb Rubber, Fly Ash and Calcium Carbide Waste

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.

Assessment of the Durability Dynamics of High-Performance Concrete Blended with a Fibrous Rice Husk Ash

The present study examines the durability properties of Class 1 (50–75 MPa) high-performance concrete (HPC) blended with rice husk ash (RHA) as a partial replacement of CEM II B-L, 42.5 N. Six HPC mixes were prepared with RHA and used as 5%, 10%, 15%, 20%, 25%, and 30% of CEM II alone and properties are compared with control mix having only CEM II. The binders (CEM II and RHA) were investigated for particle size distribution (PSD), specific surface area (SSA), oxide compositions, mineralogical phases, morphology, and functional groups using advanced techniques of laser PSD, Brunauer–Emmett–Teller (BET), X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared/attenuated total reflection (FTIR/ATR), respectively, to understand their import on HPC. Durability properties, including water absorption, sorptivity, and chemical attack of the HPC samples, were investigated to realise the effect of RHA on the HPC matrix. The findings revealed that the durability properties of RHA-based HPCs exhibited an acceptable range of values consistent with relevant standards. The findings established that self-produced RHA would be beneficial as a cement replacement in HPC. As the RHA is a cost-effective agro-waste, a scalable product of RHA would be a resource for sustainable technology.

Study on Strength and Durability Properties of Bacterial Concrete

The primary thought of this review is to assess the strength and durability properties of high strength concrete specimens by replacing cement with bacteria for healing cracks. Concrete is the most commonly used construction material all around the world. Cracks are formed due to various reasons. The cracks act as a pathway through which water and toxic salts enter. This causes corrosion and also leads to failure of structure. Repair and Rehabilitation works are costly to be done. In order to overcome this, bacteria is induced into the concrete which leads to the process of Microbial Induced Calcium Precipitate (MICP). The cracks heal by self-healing mechanism and results in crack free concrete structure. It also improves the compressive and tensile strength. In this article a new bacterium has been cultured and identified and is used as a self-healing material in M30 Grade concrete.

Impact Analysis and Structural Optimization of Crash Barriers

The primary thought of this review is to assess the impact absorbance, strength and durability properties using non-linear finite element simulations of analytical model of crash barriers. Before manufacturing and erection of crash barriers on site are generally simulated for impact performance using finite element analysis various parameters are checked such as 1) Crash performance 2) Vehicle trajectory after collision 3) Safety of the vehicular occupant.

Characterisation of Fibre Reinforced Resin Concrete

Resin Concrete uses polymeric resin to replace cement concrete. Four types of polyester resins were identified with Methyl methacrylate as catalyst, calcium carbonate and fly ash as fillers along with river sand and coarse aggregate size of 10mm, 6mm were used to produce resin concrete. Seventy-two trial batches were carried out for preliminary investigation targeting compressive strength of more than 80 MPa (11.6 ksi) and four batches were shortlisted. These four batches along with the addition of glass fiber were taken for detailed investigation of stress strain behavior, young�s modulus, Poisson ratio, various correlative equations among their mechanical properties and durability properties. Developed mix can be recommended for manufacturing various polymer products.