Expanded clay concrete (ECC) is a promising structural material for buildings due to its light weight and heat- and sound-insulating properties. Adding basalt fibers (BFs) in ECC reduces its brittleness and enhances its mechanical properties. The heat treatment (HT) of BF-reinforced ECC can significantly accelerate the strength growth during cast-in-situ construction, which allows the reduction of the turnover of the formwork and the construction period, as well as leading to lower construction costs. This paper presents an HT technology for load-bearing structures, containing a BF-reinforced ECC mix and using infrared rays for cast-in-situ construction. The issue of the strength growth of BF-reinforced ECC during HT has been studied. Microsilica and fly ash were added to the ECC mix to obtain a compressive strength of more than 20 MPa. Four different mixes of ECC with chopped BFs in the ratios of 1:0, 1:0.0045, 1:0.009 and 1:0.012 by weight of cement were studied. Test specimens were heated by infrared rays for 7, 9, 11, 13, 16 and 24 h. Then, the heat-treated specimens were tested for compressive strength after 0.5, 4, 12 and 24 h cooling periods. The analysis and evaluation of the experimental data were carried out based on probability theory and mathematical statistics. Mathematical models are proposed for forecasting the strength growth of BF-reinforced ECC during cast-in-situ construction.

In continuance to providing a reliable and cost-efficient road construction material that would aid the development of sustainable pavements while also eradicating agricultural wastes to protect the environment, Cassava Peel Ash (CPA) modified asphalt mixture is seen to be one of the most viable options. This study aimed to determine the suitability of Cassava Peel Ash (CPA) in hot mix asphalt for improved pavement performance. Using response surface methodology, a central composite design was employed for the mix design parameters, namely coarse aggregate (CA), fine aggregate (FA), mineral filler (MF), bitumen content (BC), and cassava peel ash (CPA). CPA was used as a partial replacement for filler and varied between 0% and 20%. The BC varied between 4% and 8%, the MF varied between 15% and 20%, the FA varied between 10% and 14%, and the CA varied between 46% and 52%. The interactive effect between the mix design parameters on the volumetric properties of the asphalt mixtures was evaluated. The results obtained showed the Marshall stability, flow, density, volume of the void, and void in mineral aggregates of the asphalt mixtures at 1.8037–8.045 kN, 2.7-8.22 mm, 2.0426–2.3909%, 1.094–7.966% and 55.5105–93.1393% respectively. These results indicate that the interaction of CA, FA, MF, BC, and CPA influences the volumetric properties of asphalt mixtures. From the RSM analysis, a prediction model and an optimal condition of 4.018% asphalt content, 20% cassava peel ash, 46% coarse aggregate, 10% fine aggregate, and 15% mineral filler were achieved for the asphalt mixtures. Doi: 10.28991/CEJ-2022-08-10-07 Full Text: PDF

Basalt fiber (BF) is one of the most important sustainable materials used to enhance high-performance concrete (HPC) in recent years. There are two types of BF, namely micro-BF and macro-BF. Despite that, macro-BF is a new material and there are few studies about it. A variety of standard material tests were carried out to examine the impact of MiniBars BF as well as its fractions (0.6–1.8%) on the physical and mechanical properties of HPC, including compressive strength $\left(f_{cm}\right)$, flexural strength ( $f_f$), workability, and modulus of elasticity ( $E_c$). The study applied the one variable at a time method by using an identical mix with different fractions of MiniBars BF to minimize the influence of other factors on the result of the test. Six different mixes were investigated. The experiment showed that the MiniBars BF fraction slightly affected the workability of the HPC mix. The results indicated that the small amount of MiniBars BF did not affect the $f_{cm}$ and the $E_c$ of HPC. But it has a negative effect after the dosage of MiniBars BF increased by more than 1.2%. The MiniBars BF enhanced the $f_f$ significantly even with a small percentage until it reached the optimum effect at 0.9% then drop slightly.

The percentages, lengths and diameters of chopped basalt fiber in concrete mixture have high influence on concrete strength. On the other hand, expanded clay contributes mostly in the weight reduction of the concrete hereby, giving what is called lightweight concrete. The collapse of concrete structures can be blamed to the effect of cracks that are born in the weak concrete structures. This paper shows how expanded clay with chopped basalt fiber of length 20mm, diameter 1.5µm affected the maximum load that the concrete samples bear and how the existence expanded clay and basalt fibers affect the concrete in terms of resistance to cracks seen through the bending (flexural) and strength on compressive of the concrete samples. The purpose of this research paper is to investigate the effect of chopped basalt fiber with expanded clay in strengthening the mechanical behaviour of concrete. Concrete specimens were mixed with chopped basalt fiber and casted, the strength checked on 7th, 14th and 28th day and evaluated based on flexural strength, compression strength. The addition of basalt fiber in the specimens showed significant effect where the compressive strength decreased while the flexural strength increased.