Partial Replacement of Cement with Bagasse Ash in Hot Mix Asphalt

Several waste and used materials from different sources are generated every day in large quantities. However, these wastes have been found to be useful in the stabilization and/or improvement of construction materials. Amongst these techniques is the use of Bagasse Ash (BA). It is in this light that a laboratory based investigation for the replacement of cement with BA in Hot Mix Asphalt (HMA) was conducted. Tests on the suitability of materials used and their performance in terms of known engineering properties was carried out. Bitumen content of 4.5%, 5.5%, 6.5% and 7.5% was adopted. The focus involves the partial replacement of cement with BA in the following order, 0% (control), 10%, 20%, 30%, 40% and 50%. Seventy-two mix specimens were produced. The results obtained shows that the Cement/BA mixes exhibit satisfactory trend result with an average bitumen content of 5.5%.The results obtained shows that stability increases as BA content decreases, flows at 5.5% bitumen Content was observed to be fairly constant at roughly 2.5mm, the per cent air voids in the mix decreases with increasing bitumen content, the VMA values all fall within specification except for 30% BA replacement, the VMA value was 16% at 5.5% of Bitumen Content. Therefore, the Cement/BA mixes exhibit satisfactory trend results with an average Bitumen content of 5.5%.http://dx.doi.org/10.4314/njt.v34i4.5

Performance of Metakaolin as Partial Replacement of Cement in Hot Mix Asphalt

Metakaolin is one mineral admixture that appears to have significant potential for the production of high strength and high performance concretes. This work investigates the performance of asphalt concrete containing Metakaolin partially replaced with cement. Oxide composition test on Metakaolin, tests on aggregates and cement, bitumen tests (consistency test) were carried out. Several mix containing different percentages of Metakaolin and ordinary Portland Cement was prepared to evaluate its strength using Marshall Stability Method of pavement design. It was found that at varying percentages of bitumen content, the stability, flow, voids in mixed aggregates and void in the mix meets the standard specified with an optimum bitumen content of 5.5%

Minimum Thresholds of Monte Carlo Cycles for Nigerian Empirical-Mechanistic Pavement Analysis and Design System

Monte Carlo simulation has proven to be an eective means of incorporating reliability analysisinto the Mechanistic-Empirical (M-E) design process for exible pavements. Nigerian Empirical-Mechanistic Pavement Analysis and Design System procedure for Nigeria Environments has beenproposed. This work aimed at providing most appropriate number of Monte Carlo simulationcycles that should be adopted for used to provide enough sucient repeatability for damage re-liability relationship in the Nigerian environments. Two selected fatigue distress models and aselected rutting distress models were evaluated for Nigerian environment. It was observed thatMonte Carlo simulation cycle of 2, 500 thresholds were enough to be used to provide sucientrepeatability for damage reliability relationship and that axle weight has an overwhelming eecton the output variability as an increase in applied load was highly noticed in the reliability values.Keywords: pavement distress, fatigue, rutting, mechanistic-empirical, Monte Carl