Cement stabilised rammed earth. Part A: compaction characteristics and physical properties of compacted cement stabilised soils

Rammed earth is used for load bearing walls of buildings and there is growing interest in this low carbon building material. This paper is focused on understanding the compaction characteristics and physical properties of compacted cement stabilised soil mixtures and cement stabilised rammed earth (CSRE). This experimental study addresses (a) influence of soil composition, cement content, time lag on compaction characteristics of stabilised soils and CSRE and (b) effect of moulding water content and density on compressive strength and water absorption of compacted cement stabilised soil mixes. Salient conclusions of the study are (a) compaction characteristics of soils are not affected by the addition of cement, (b) there is 50% fall in strength of CSRE for 10 h time lag, (c) compressive strength of compacted cement stabilised soil increases with increase in density irrespective of moulding moisture content and cement content, and (d) compressive strength increases with the increase in moulding water content and compaction of CSRE on the wet side of OMC is beneficial in terms of strength.

Barriers to plantation activities in different agro-ecological zones of Southern India

This paper analyses environmental and socio-economic barriers for plantation activities on local and regional level and investigates the potential for carbon finance to stimulate the increased rates of forest plantation on wasteland, i.e., degraded lands, in southern India. Building on multidisciplinary field work and results from the model GCOMAP, the aim is to (1) identify and characterize the barriers to plantation activities in four agro-ecological zones in the state of Karnataka and (2) investigate what would be required to overcome these barriers and enhance the plantation rate and productivity. The results show that a rehabilitation of the wasteland based on plantation activities is not only possible but also anticipated by the local population and would lead to positive environmental and socio-economic effects at a local level. However, in many cases, the establishment of plantation activities is hindered by a lack of financial resources, low land productivity and water scarcity. Based on the model used and the results from the field work, it can be concluded that certified emission reductions such as carbon credits or other compensatory systems may help to overcome the financial barrier; however, the price needs to be significantly increased if these measures are to have any large-scale impact.

Seismic Microzonation: A Tool for Disaster Mitigation Planning

Seismic microzonation has generally been recognized as the most accepted tool in seismic hazard assessment and risk evaluation. In general, risk reduction can be done by reducing the hazard, the vulnerability or the value at risk. Since the earthquake hazard can not be reduced, one has to concentrate on vulnerability and value at risk. The vulnerability of an urban area / municipalities depends on the vulnerability of infrastructure and redundancies within the infrastructure. The earthquake risk is the damage to buildings along with number of people that are killed / hurt and the economic losses during the event due to an earthquake with a return period corresponding to this time period. The principal approaches one can follow to reduce these losses are to avoid, if possible, high hazard areas for the siting of buildings and infrastructure, and further ensure that the buildings and infrastructure are designed and constructed to resist expected earthquake loads. This can be done if one can assess the hazard at local scales. Seismic microzonation maps provide the basis for scientifically based decision-making to reduce earthquake risk for Govt./public agencies, private owners and the general public. Further, seismic microzonation carried out on an appropriate scale provides a valuable tool for disaster mitigation planning and emergency response planning for urban centers / municipalities. It provides the basis for the identification of the areas of the city / municipality which are most likely to experience serious damage in the event of an earthquake.