Sulfate attack and embedded steel corrosion resistances of volcanic-aggregate concrete with fly ash and silica fume

Construction materials are increasingly on high demand in the developing world. The construction industry has a challenge of discovering, new  alternative construction materials to conventional materials which are locally available materials in environmentally friendly manner. The  experimental tests are conducted on volcanic concrete system to analyze its properties especially corrosion resistance potential for its applicability in construction. The major aim is to investigate its suitability and corrosion resistance potential especially when used in construction of structures with embedded steel. The test results of the material show that volcanic concrete system with 30% fly ash and 10% silica fume cementing materials is an alternative green construction material. Permeability properties are reduced by 8% and 24% with 30% fly ash and 10% silica fume respectively. Tests also indicate that Compressive strength, Corrosion potential and polarization resistance in volcanic concrete system with supplementing  cement materials has more potential to resist sulfate attack when compared with conventional volcanic concrete systems. The supplementary cementing materials (SCM) reduce the pore system and hence decrease the ingress of corrosive ions an  water in concrete. Corrosive ions, moisture and air would initiate corrosion to the embedded steel in concrete leading to reduced service life such structures. Key word: Supplementary Cementing Materials, Sulfate attack, volcanic concrete system, Granite powder, river sand, Corrosion of embedded stee

Strength, sustainability and affordability of bamboo and mud bricks as materials used in local construction

The construction industry is one of the rapidly growing and the cost analysis suggests that the materials cost is constantly increasing. The continuous extraction of aggregates intensively used in the field is negatively acting to the environment. Therefore research in construction materials should focus not only on discovering new alternative materials but also in appreciating the quality of those locally available for their better application. This research aimed at evaluating the performance of bamboo and mud bricks as two available local building materials, especially with regards not only to their strength but also to new performance concepts which are affordability, energy efficiency and environment friendly aspects. The study comprised mainly of laboratory tests of used materials and cost estimation analysis. Study results established that the considered bamboo and mud bricks, made in ordinary soils and reinforced by sisal fibers were reusable, environment friendly materials and energy efficient, with the bamboo showing the thermal conductivity equal to 0.1496 W/mK. Regarding the compressive strength, reinforced mud bricks with sisal fibers showed an increased value from 1.75 MPA to 4.29MPA, what was in line with related previous studies. The average compressive strength of the studied Arundinaria Alpine bamboo was established at 133,7MPA, while its tensile strength was 88.16MPA and these values were reasonable with comparison to other conventional materials. It is recommended that further research in checking the performance of other types of bamboo as well as about new construction technologies be undertaken in order to enhance the service life of both bamboo and mud bricks.Keywords: Affordability, Bamboo, Conventional concrete, Materials strength, Mud reinforced bricks, Sustainabilit

Investigation on application of Rwanda building standards in local construction industry

The Rwanda Building code is in place from 2015, while the development of Rwanda standards dates from 2006 when the reviewed Law establishing Rwanda Bureau of Standards (RBS) was published. The key role of standards is technically to ensure quality, safety, reliability of constructions as stated the relevant codes. With the construction industry growing very fast, the purpose of this study was to investigate on the application of Rwanda building standards, with regards to the existing code requirements and to identify the relevant gaps. The study was conducted based on initially set specific objectives, while the research methodology was mainly comprised of visits to different public and private agencies related to construction industry, observations on the sites and interview with different experts. The study established that Rwanda building standards were still accused of a low awareness and application as well as noticeable gaps. The level of awareness among all professionals was still at 71%. In general about application, only 55% of respondents confirmed the experience in application of Rwanda building standards, even if this level was higher for some categories. A good part of respondents composing around 57% thought that Rwanda building standards documents were still incomplete. Based on the above findings, adequate strategies for improving the awareness, application process and document completion were proposed; with the introduction of Rwanda building standards into academic curriculum, increase the number of awareness meetings and recognition of adequate research before design or review of any standard, among others.Keywords: Building code, Building Standards, awareness strategy, Law and Regulations, Monitoring proces