The Egyptian rice yield is one of the highest in the world (9
Over the past ten years burning rice straw has become a tragic environmental event that produces black clouds of smoke, the cause of a high degree of pollution, especially to the population of Cairo.Using rice straw bales (RSB) in construction is a pioneering step in Egypt to solve this uncontrolled environmental problem. Although this technique has been shown to be strong and durable throughout the world in both load-bearing and post-and-beam structures, it is not yet a well acquainted technique in Egypt.This research is a part of an ongoing global project that aims to test and demonstrate the use of straw bales as a building unit. This preliminary step is aimed at providing a baseline for establishing an appropriate addition to the Egyptian Building Codes using this non-traditional, sustainable, environmentally friendly building unit.This paper aims to test the compression strength, modulus of elasticity and modulus of rupture of some Portland cement and lime plaster mixes. The results of this stage of research are intended to recommend the most appropriate cement plaster mix to be applied on the straw bale walls with respect to the structural behaviour. A comparison between the results of those tests and others reported in some previous published literature will also be discussed in this paper.
Background: The marble and granite industries in Egypt produce a vast amount of by-product slurry waste that could be used in green mortar production suitable for construction purposes. This research highlights the effect of the chemical constituents of marble and granite waste powders on the compressive strength of the green concrete produced. A chemical analysis of the constituents of granite and marble wastes was compared with those of the cement to study the effect of these components on the hydration reaction inside the mixture. The experiment was based on replacing the same proportions of sand and cement in the green concrete mixes with each of granite and marble waste powders after dissolving it in the water content. Results: The study revealed that by replacing 5% of cement in (NC5) mix, 10% of sand in (NF10) mix, as well as 5% of cement and 10% of sand in (NC5 + NF10) mix, by granite waste powder, the compressive strength values increased by 33%, 39%, and 41%, respectively. This was due to the presence of more than 26% fine free silica particles in granite which undergo pozzolanic reaction with calcium hydroxide present in mortar pores producing calcium silicate hydrate (CSH) crystals resulting in high strength to the cement mortar. For the same mixes containing marble powder, the compressive strength showed less values by − 14%, 10%, and 0% for NC5, NF10, and NC5 + NF10 mixes, respectively, when compared to the control mix values. Conclusion: Although the waste particles worked as filler, it was observed that its presence in the mixture improved the particle packing and increased the cohesion of the composites.
Abstract. Better understanding of the properties of cement-based materials, one of the most widely used building materials, at the nano-scale is crucial to improve its functionality in the built environment. This paper presents areas of using nano-materials in improving the characteristics of cement-based materials as well as introducing a new role of nanotechnology together with waste management in enhancing the concept of sustainable construction.A case study on the use of nano-granite waste particles as a replacement of cement and fine aggregate in mortar production is presented.The research concluded that replacing 5% cement and 10% sand with nano-granite waste in the mortar mix increased the compressive strength of the green mortar by 41% compared to that of the control mix (CM). SEM images reinforced this result as the green mortar mix showed maximum density and minimum micro cracks and number of pores.A comparative study between the green mortar and traditional mortar was carried out using sustainability indicators to examine the environmental, social and economic implications. The environmental and social attributes showed a saving of 10% in the field of resource consumption, whereas savings in energy consumption and CO2 emissions reached 5%. The economic field showed saving of 6.5% indicating promising results in enhancing the sustainable construction industry.
The use of plastered straw bales for wall construction in residential and light commercial buildings has increased significantly all over the world. The performance of straw bale walls under fire exposure is an item of major importance in securing construction.This paper presents a fire resistance test on different cement plaster mixes applied on straw bales of thickness 45 cm. The test was conducted on the samples' surface for almost 2 hours using direct flame. A thermal sensor was installed on the sample side opposite to the flame side to record the transmission of heat through the plastered bales. The results showed that bales survived fire penetration in excess of 2 hours after which the flame was discontinued.It was concluded that mixes containing higher percentages of cement content exhibit more fire resistance than those with less cement content. It was also noticed that the increase in heat transmission through the bales (between both sides) did not exceed 5°C in all samples.
Straw, as a fi ber, has been used as part of building materials for several years. A carefully constructed strawbale building has excellent thermal performance because of the combination of the high isolative value of the bales and the thermal mass provided by the thick plaster coating of the interiors. This paper addresses the thermal performance of rice straw bales and walls plastered with different cement plaster mixes. The plaster mixes are applied on straw bales of thickness 45 cm. A fi re resistance test is conducted for two complete h°urs on the bales using direct fl ame after which the fl ame was discontinued. According to the test results, the mix with equal parts of cement and lime showed acceptable mechanical properties. This mix is chosen to be applied on a prototype straw bale wall compartment with an aim to evaluate the thermal performance of the plastered straw bale walls in arid desert climate at the hottest month of the year in Egypt. The straw bale wall test is undertaken by collecting actual measurements on site. Thermal sensors are installed on both external and internal sides of the wall to record the heat transmission through the plastered walls. The results showed that all the plastered bales survived fi re penetration for the life period of the test. Increasing the lime content and decreasing the cement content of the mix raises the possibility of weak areas in the plaster of straw bale walls causing cracks during direct fi re exposure. Similar width and density of the bales for all the specimen mixes didn't affect the heat transmission through the bales, which did not exceed 5.3°C in all samples. The site readings on the straw bale walls showed high range of temperature fl uctuation on the external wall sensor, while in the internal wall sensor the temperature fl uctuation was kept to minimum values. It was concluded that due to their high thermal insulation, straw bale structures require comparatively less energy to sustain thermal comfort conditions.
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