Coal ash is a by-product from coal-fired power plants that generates electricity. These waste materials most of the time is kept in storage facilities. Due to the growing demand in electricity generation, storage facilities can no longer accommodate the waste materials. Instead of disposing the waste materials, it can be used as a construction material. A promising civil engineering structure that can use coal ash as a construction material is land reclamation. The structure needs huge volume of materials and this can maximize the usage of coal ash. In the Philippines, most land reclamation projects are conducted at the sea. From this, distilled water was replaced with sea water to have a better evaluation of the strength properties of coal ash. Consolidated drained test was performed having three conditions with respect to sea water exposure. First condition is no exposure, second condition is immediate exposure and third condition is prolonged exposure. Results show that coal ash exposed to seawater, immediate and prolonged, has smaller shear strength. On the other hand, it still has reasonable strength suitable for land reclamation projects. Constitutive modeling using Modified Cam Clay model is incorporated in the study to be able to predict its behavior and failure in terms of mean effective stress, deviator stress and specific volume.

Cebu province is considered to be one of the most developed provinces in the Philippines with 2.94 Million population. Last October 2013, a Magnitude of 7.2 earthquake affected the province and left a death toll of 222. Many of the cultural heritage structures were affected, and with this it is important that seismic assessment is performed for the province of Cebu. Information regarding its vulnerability to earthquake damages is needed to lessen the casualties. In this study the structures were assessed though Probabilistic Seismic Hazard Assessment and thoroughly characterized qualitatively according to Low, Medium and High Priority by Geographic Information System (GIS). These characterizations may be used as basis for seismic provisions in building codes, budget allocations for risk reduction and for risk models.

Mining minerals results in a waste material called mine tailings. In the Philippines, these waste materials are considered valueless and are just stored at tailing dams. The increasing demand for gold minerals in the country can cause an increase in the production of these waste materials. This can lead to a shortage of storage facilities. With this, this study used Philippine gold mine tailings as a material for geopolymerization. The process of geopolymerization produces a cementitious material with properties substantially comparable to those of conventional cement. It occurs after an aluminosilicate material reacts with an alkali hydroxide or silicate solution. In this study, gold mine tailings were mixed with the alkaline solution, or the combination of the 10-molar sodium hydroxide solution (10M NaOH) and the Water Glass Solution (WGS), to produce the geopolymer. A total of a four-mix proportion of WGS-to-10M NaOH and Alkaline Solution-to-Mine Tailings (AS-to-MT) was tested in this study. The compressive strength of each mix proportion was compared. Based on the results, the highest compressive strength has a mixed proportion of AS-to-MT ratio of 0.35 and the WGS-to-10M NaOH solution ratio of 2.5. X-Ray Diffraction was also performed to determine the chemical compound present in the gold mine tailings used. The results show that aluminum and silicon compounds are present in the material, hence, making the gold mine tailings viable for geopolymerization.

No abstract

Philippines, with a total of 7,107 islands, have one of the largest mineral resources in the world. The copper and gold deposits are considered to be among the largest in the world (Bureau of East Asian and Pacific Affairs, 2010). Mining minerals generate waste material called mine tailings. Impoundment of mine tailings is normally done to store these waste materials. One of the most common types used in impounding tailings is raised embankments because of its low economic cost. This impoundment uses natural soil, tailings, and waste rocks as the construction material. There are cases that raise embankments experience stability failure which can affect the environment and well-being of the community where it is situated. It is the interest of this study to assess the possibility of using mine tailings, specifically copper tailings, as a construction material. Index properties were first established following ASTM standards. From this, it was established that the copper tailings has plasticity. Unconsolidated undrained, consolidated undrained and consolidated drained test were conducted to determine the critical shear strength of the copper tailing. The copper tailings were tested having two relative densities namely, 60% and 90%. The effective critical angle of friction was found to have a range of 21°-28°. Since critical-state parameters are considered in the study, Cam clay model can be implemented so that to its behavior and failure mechanism can be predicted.