The impact of rubber crumb on the mechanical and chemical properties of concrete

Various works have been carried out on both the physical and mechanical properties of rubberized concrete in previous research. But the chemical composition of rubberized concrete has not been fully investigated. The scanning electron microscopy (SEM) and energy-dispersive x-ray spectrum (EDX) analysis were used to determine the element composition and the peak intensity of chemical elements in the waste rubber concrete. The SEM and EDX analysis results showed that, ferrous iron, oxygen, calcium, and silicon were the dominant elements, and these elements reduced as more waste rubber were added to the concrete. Carbon and sulphur elements increased as rubber crumbs were added to the rubberized concrete. The work concluded that the presence of rubber crumb in the concrete samples contributed to both mechanical and chemical changes in the property of rubberized concrete

Production of lightweight concrete from waste tire rubber crumb

A lot of research has proposed the use of alternative materials in concrete, one of such material that has gained a lot of attention is the waste tire rubber. In this research, rubber crumb was used to partially replace fine aggregate in concrete at 0, 4, 8, 12, and 16% and represented as M0, M4, M8, M12, and M16, respectively. Sieve analysis was carried out on the rubber crumb and sand, while slump, compressive and tensile test were carried out on the concrete samples. The sieve analysis revealed that both the fine aggregate and rubber crumb are poorly graded. The slump test showed that the concrete losses it consistency as more rubber crumb was added. The 28 days compressive strength showed that there was a general reduction in strength. The work concluded that rubber crumb can be used to replace fine aggregate up to 16%, in lightweight concrete

Use of Sustainable Materials in Self-Healing Concrete

Vulnerability to cracks is one of the major flaws of concrete infrastructure. The need to reduce the repair cost of this defect birthed the need for self-healing concrete. The incidence of cracks on concrete structures is a big threat to the stability of bridges, concrete roads, and other concrete infrastructures. This review assessed the use of self-healing technology on concrete using sustainable material as an active method of healing crack. This was done with the view of improving the stability, strength, and sustainability of infrastructure for national growth. The outcome of the review showed three prominent methods used in self-healing technology, which include autogenous healing, encapsulation of polymeric material, and microbial production of calcium-carbonate (biotechnological approaches). The review also revealed that calcium carbonate is a versatile material that can be used in crack healing for the filling of voids and improves the porosity of the concrete. The success of using the autogenous healing method depends on the diameter of the crack induced in the concrete structure. Additionally, this method can operate independently in different conditions regardless of the crack position. Correspondingly, lowering the water-cement ratio improves the autogenous healing process. The use of encapsulation of polymeric material and microbial production of calcium-carbonate methods showed that the presence of water and humidity is a critical factor to be considered. However, biotechnology using microbial action is prone to the production of ammonium ions (NH4+) through ureolytic activity, which results in nitrogen oxide emission into the atmosphere. Congruently, this may affect the durability of the concrete. Based on the uniqueness of this technology, it is recommended for the construction of sustainable infrastructure now and in the foreseeable future

Design and Performance Evaluation of Horizontal- Shaft Palm Kernel Cracking Machine

The need to support the small and medium scale industries involved in palm kernels, led to the design, fabrication and evaluation of a horizontal shaft palm kernel cracking machine. All the materials were sourced locally in Nigeria which makes it affordable for small and medium scale farmers involved with palm kernel. The basic features of the machine include a horizontal shaft, hopper, cracking chamber, pulleys, bearings with housing, discharge outlet and electric motor (prime mover). The mean efficiency of the machine under good operating conditions is 75.5%. The production cost of the machine excluding electric motor was estimated to be one hundred and fifty-one dollar forty-sixcents (US$151.46), based on the exchange rate when it was manufactured. The cost can further be reduced, if mass-produced

Permeable pavements for storm water control incorporating nano clay

Stormwater affects the economic situation of the environment, changes the land use, which also affects the ecosystem. Consequently, this affects the pavement condition of the road and lead to both structural and functional pavement defects. In a bid to proffer solution to the harmful effects of stormwater and reduce the cost of pavement construction in track with sustainability, this research utilized nano clay in the development of permeable concrete. The nano clay was used as a partial replacement for cement. It was dehydroxylated at 720°C; the characterization and particle geometry was done using the XRF equipment. The de-hydroxylated nano clay was used as a partial replacement for cement at 5, 10, 15, 20 and 25%. Correspondingly, six samples of concrete were developed. The mechanical properties (compressive and flexural strength) of the permeable concrete was assessed at 3, 7, 14, 21 and 28 days. Additionally, the porosity of the concrete was determined using Archimedes principle. The result of the research showed that using nano clay replacement at 15% gave a flexural strength of 4.01MPa. This is lower than the required specification of 4.27Mpa—4.5MPa for pavement construction at 28 days and 4.5Mpa and above for airfield pavement. The porosity test using Archimedes principle showed a satisfactory result. This proves the efficiency of the concrete for stormwater control. Therefore, this concrete is recommended for use in the design and construction of low axle or low trafficked road for stormwater control and aquifer recharge based on the flexural strength

Characterization of Bitumen Extracted from used Asphalt Pavement

The objectives of the research were principally to characterize extracted bitumen from Used Asphalt Pavement (UAP) on twelve selected roads through the determination of engineering properties (penetration and viscosity) and establishment of appropriate mathematical relationship between principal parameters of the extracted bitumen. Laboratory tests were carried out on three samples from each of the roads in order to obtain extracted bitumen characteristics.  Established equations and regression analysis were used to study and compare the behaviour of the extracted bitumen with existing national standards. The extracted bitumen from the mix was 5.00 – 6.40 %, which fell within the 5.00 – 8.00 % range specified.  Weak correlations existed between the actual age of the road and bitumen content with coefficients of determination of 8E-05 to 0.0943 for linear, exponential, logarithmic, quadratic, and fourth order polynomial.  The effect of the age of the road on the penetration and viscosity of the binder respectively indicated fair relationship with coefficients of determination ranging from 0.5361 to 0.6351.  The study showed that extracted bitumen may be reused for asphalt concrete pavement needed for road construction leading to preservation of environment and reduction in land filling.                                                                                                                                                           Keywords: Used asphalt pavement, Road construction, Extracted Bitumen, Coefficient of Determinatio

Optical properties of bimetallic (SrO-K2O) nanofillers

Abstract : In this study, bimetallic nanofiller capable of usage as reinforcement was synthesized from expanded polystyrene (EPS). Bimetallic materials consist of two different metals. The bimetallic nanofiller consisting of SrO and K2O was successfully developed by the hydrothermal method which many researchers have well utilized to prepare nanoparticles in recent times. This study aims to synthesize and characterize bimetallic SrO-K2O, nanofillers from recycled expanded polystyrene (EPS). Products obtained were characterized by Zeta potential and Raman spectra. The Zeta potential was used to determine the surface charge of the nanofillers in solution. The Raman spectroscopy was used to determine the crystalline structure of the nanofillers. Based on the results, it was concluded that stability of nanoparticle materials in acidic medium decreases as the pH increases, and for the basic medium, stability reduces with decrease pH. The mixture of SrO and K2O to form SrO-K2O bimetallic oxide affects the stability of the nanofillers produced both in the acidic and basic medium. The Raman spectra indicated the Dband and Gband of the synthesized SrO, K2O and bimetallic SrO-K2O at 1006, 1008 and 1004 cm-1 and 1598, 1610 and 1606 cm-1 respectively. It was concluded that the shift in band gaps were because of structural changes in the molecules of the recycled expanded polystyrene

Development and size distribution of polystyrene/ZnO nanofillers

Abstract : In this paper, the preparation and characterization of ZnO nanofillers from polystyrene (PS) polymer waste for use as reinforcement was presented. This was done to achieve a better means of upcycling polymer wastes that have become social menace in recent times. The PS/ZnO nanofillers was synthesized through the hydrothermal synthesis of nanocomposites in an enclosed reactor. The reactor was kept in an oven at a specified temperature for a period. A product obtained was characterized using Fourier transform infrared (FTIR) analysis and Particle size analyser (PSA). The FTIR was utilized to determine the functional groups present in the synthesized nanofillers. The Particle size analyser was used to determine the distribution of particle size within the polymer matrix. The absorption peak obtained in the FTIR analysis confirmed the presence of ZnO in the synthesized material and the results from particle size analysis showed that about 80% of the particle was accommodated within the whole sample