Porous concrete technology has been used since 1970s in various parts of the United States
as an option in complex drainage systems and water retention areas. Porous concrete pavements have
become popular as an effective stormwater management device to control stormwater runoff in
pavement. Porous concrete pavement is being used as one of the solutions to decrease the stormwater
runoff by capturing and allowing rainwater to drain into the land surface. The main problem of porous
concrete pavement is its strength. The objective of this paper is to review the use and performance of
nano silica in porous concrete pavement and previous laboratory study on porous concrete pavement.
From the literature review, it was found that the conventional porous concrete pavement does not have
good strength for pavement purpose. An addition of nano-material will improve the physical and
chemical properties of porous concrete pavement. To improve the strength of the porous concrete,
various additives have been studied as a part of porous concrete mix and yet, the optimum condition to
produce good porous concrete has still not been established. From the previous study, it was found that
in preparing the porous concrete laboratory specimen, the use of standard Proctor hammer (2.5 kg)
and pneumatic press (70 kPa compaction effort) resulted in the closest properties to the field porous
concrete.
This study investigated the influence of coal bottom ash (CBA) on the concrete properties and evaluate the effects of combined exposure of sulphate and chloride conditions on the concrete containing CBA. During concrete mixing, cement was replaced with CBA by 10% of cement weight. Initially, concrete samples were kept in normal water for 28 days. Next, the specimens were moved to a combined solution of 5% sodium sulphate (Na2SO4) and 5% sodium chloride (NaCl) solution for a further 28 to 180 days. The experimental findings demonstrated that the concrete containing 10% CBA (M2) gives 12% higher compressive strength than the water cured normal concrete (M1). However, when it was exposed to a solution of 5% Na2SO4 and 5% NaCl, gives 0.2% greater compressive strength with reference to M1. The presence of 10% CBA decreases the chloride penetration and drying shrinkage around 33.6% and 29.2% respectively at 180 days. Hence, this study declared 10% CBA as optimum that can be used for future research.
Concrete mix design and the determination of concrete performance are not merely engineering studies, but also mathematical and statistical endeavors. The study of concrete mechanical properties involves a myriad of factors, including, but not limited to, the amount of each constituent material and its proportion, the type and dosage of chemical additives, and the inclusion of different waste materials. The number of factors and combinations make it difficult, or outright impossible, to formulate an expression of concrete performance through sheer experimentation. Hence, design of experiment has become a part of studies, involving concrete with material addition or replacement. This paper reviewed common design of experimental methods, implemented by past studies, which looked into the analysis of concrete performance. Several analysis methods were employed to optimize data collection and data analysis, such as analysis of variance (ANOVA), regression, Taguchi method, Response Surface Methodology, and Artificial Neural Network. It can be concluded that the use of statistical analysis is helpful for concrete material research, and all the reviewed designs of experimental methods are helpful in simplifying the work and saving time, while providing accurate prediction of concrete mechanical performance.