Muhammad Naqiuddin Mohd Warid

Potentials of steel slag and copper mine tailings as construction materials

Abstract The present rate of utilisation of mine waste in a country like Malaysia is rather below expectation compared with some advanced countries. Many studies concentrate on a better way to increase the usage of industrial byproducts in order to ease disposal problems. Enormous quantities of steel slag and copper mine tailings are deposited in yards, polluting the environment. Researchers need to pay attention to the effective use of industrial byproducts in construction to address economic and environmental concerns. The potential uses of copper mine tailings and steel slag need to be explored and the negative impact of mine tailings should be reduced by exploring potential uses of these waste materials in the construction industry. Although copper tailings have negative effects on the environment owing to their acidic content, they also have some great economic value in terms of valuable metal contents. The engineering properties of steel slag and copper mine tailings were reviewed and their various areas of application are highlighted.

Performance of warm-mix asphalt in the highway industry

Abstract Warm-mix asphalt (WMA) technologies could address the problem of deterioration of roads, reduce escalated energy costs and increase environmental awareness. This technology allows significant reduction in temperature for construction and paving of roads compared to conventional hot-mix asphalt (HMA) paving. In HMA production, the quarry mixing and paving temperatures are equivalent to bitumens viscosity of 170 and 280 cP, respectively, for a proper coating of aggregates and field paving. But in WMA, the viscosity of bitumen is reduced and increases the workability of the mixture. Sasobit and asphamin are the two major additives used with bitumen or in batching plant for the production of WMA. Besides, complex shear modulus (G*) is used to determine the rutting (G*/Sinδ) and fatigue factors (G*Sinδ) to control the deterioration of roads. A further study is needed to monitor the overall performance of WMA in the context of pavement temperature.

Influence of diatomite filler on rheological properties of porous asphalt mastic

ABSTRACT Mineral filler is usually added into asphalt mixture to stiffen the asphalt binder and improve mixture strength. This is particularly important for open gradations such as porous asphalt which is known to have poor strength and durability because of its open nature and large air voids. The interactions that occur between asphalt binder and filler results in certain mastic properties that affect the mixture strength. In this study, the effect of different types of filler on the rheological properties of asphalt–filler mastics for porous asphalt were evaluated using the frequency sweep and multiple stress creep recovery (MSCR) tests. Hydrated lime, cement and diatomite with 2% content were selected to produce asphalt–filler mastic. The influence of diatomite filler was investigated and compared to the hydrated lime and cement fillers. Results indicated that the use of filler increased the stiffness of mastics. The MSCR test showed that hydrated lime and diatomite mastics exhibited the lowest non-recoverable compliance and high recovery than the original PG 76 binder and cement mastic. Diatomite mastic exhibits the best resistance to rutting at high temperatures and stress levels, verifying that the use of diatomite filler is favourable because of its high temperature properties.

Thin cold-mix stone mastic asphalt pavement overlay for roads and highways

Abstract This paper presents the latest development in the design of thin cold-mix stone mastic asphalt (SMA) pavement using modified bitumen emulsion that addresses the topmost global issues, environmental pollution and energy crisis. The hot-mix asphalt (HMA) pavement is generally known to have higher strength and is more durable compared to others, but have some disadvantages on environment, economy and safety-related issues. Cold-mix asphalt (CMA) pavements are widely used because of its simple technique and easy to construct. Currently, there are no established standards and specifications of mix design for CMA, especially for gap-graded pavement in Malaysia, and the laboratory test results are inconsistent. The use of 4·75mm nominal maximum aggregate size (NMAS) for the HMA has the highest potential for preventive and reactive maintenance of roads. Further study is needed to design and develop 4·75mm NMAS cold-mix SMA pavement in order to achieve and produce a cost-effective sustainable pavement.