Websjournal of Science and Engineering Application ISSN: 1974-1400-X, Vol 2, No 1, 2013, 8-15 . S.O. Ajamu and A A. Adedeji 50 Websjournal of Science and Engineering Application//Lyon _ AIGEN INVESTIGATING THE BEARING CAPACITY OF STRAW BALE MASONRY IN COMPRESSION AND THERMAL LOADS S.O. Ajamu 1 and A. A. Adedeji 2 1 Department of Civil Engineering, Ladoke Akintola University of Technology,PMB 4000, Ogbomoso, Nigeria soajamu@lautech.edu.ng or ajamubenchmark23@yahoo.com 2 Department of Civil Engineering, University of Ilorin, PMB 1515 Ilorin, Nigeria. aaadeji@unilorin.edu.ng or aadeoladeji@yahoo.com Corresponding author: aaadeji@unilorin.edu.ng , aadeoladeji@yahoo.com ABSTRACT This study determines the optimum cement plaster thickness for straw bale prism and the compressive strength of the resulting composite prisms. The thermal insulation property of a prototype building made with the prisms was also compared with a prototype building of the same size but made of solid sandcrete block. The material of straw used is that obtained from guinea corn stalk. The plaster thickness corresponding to the optimum density of the prism was found to be 25mm, the average compressive strength was found to be 0.8N/mm 2 . The thermal insulation capacity of straw bale wall was compared with that of sandcrete solid block wall by comparing the cooling rate (curve) of internal temperatures of the two prototype buildings that were subjected to same high initial temperature conditions. It was observed that temperatures fell slowly at first in the solid sandcrete block and later became faster relative to that of the prototype building made with straw bale wall. This result showed that strawbale walls have a higher thermal insulation capacity compared to (solid) sandcrete block walls. Keywords: Strawbale wall, Compressive strength, thermal insulation, plasters thickness, density 1. INTRODUCTION Strawbale construction uses baled straw from wheat, oats, barley, rye, rice and others in walls covered by cement plaster. Straw bales are made from plants’ wastes which farmers do leave on the farm. It is the dry plant material or stalk left in the field after a plant has matured as shown in figure 1, been harvested for seed, and is no longer alive. It is usually burned, causing severe air quality problems. The seed heads of the plants are what the farmer wants to harvest. Once they are removed, the stalks are baled into a great building material (Chris, 2005). Common bales come in either two- or three-string sizes, with roughly standard dimensions. Figure 1: A guinea corn plantation 2. TYPES OF STRAWBALE WALL There are two primary ways of building with straw bales: (i) Load bearing or Nebraska style and (ii) Post and beam / in - fill / non- load bearing method. WEBSJOURNAL OF SCIENCE AND ENGINEERING APPLICATION WESEA ISSN: 1974-1400-X, Vol 2, No 1, 2013, 50-58