Pemanasan yang dialami beton akibat terbakar akan mengakibatkan perubahan mendasar dari sifat-sifat beton. Atas dasar hal tersebut, maka tujuan dari penelitian ini adalah untuk mengetahui gambaran kuat tekan setelah terbakar dan model hubungan antara temperatur dan kuat tekan beton. Benda uji yang digunakan berbentuk kubus ukuran 15cm x 15cm x 15cm. Pemanasan dilakukan dalam oven pada temperatur 200 o C-600 o C dengan interval kenaikan 50 o C. Analisis data dilakukan dengan analisis statistik deskriptif dan analisis regresi. Hasil penelitian menunjukkan bahwa kuat tekan beton rata-rata menurun dengan adanya kenaikan temperatur.

The purpose of this study is to identify the competencies of vocational high school graduates and describe strategies for the achievement of these outcomes. This study formulates particular competencies required by the construction industry. The research method is quantitative. Data of competence graduates obtained by distributing questionnaires at 45 construction industries in Makassar. These industries are represented by three types of consultants which are planners, supervisors, and contractors. Furthermore, data competency achievement strategies obtained by questionnaire at five vocational technologies education experts. The construction industry needs analysis using descriptive methods. The strategy analysis was carried out by the method of analytical hierarchy process (AHP). The results showed that the primary competence of graduates, especially in attitude is confidence in the completion of work. In knowledge aspects, the graduates must have procedural knowledge about constructions method. In the aspect of skill, graduates should have the creativity in problem-solving. External strategy for achieving competence of graduates based on expert opinion is the development of teaching factory in schools, while internal strategy is development learning model.

Cement production, which results in higher CO2 levels, has a negative impact on environment. This phenomenon has caused the emergence of a new type of environmentally friendly cement, such as Portland Composite Cement (PCC). On the other hand, rainfall becomes high acidity level. This will be an issue in the construction of concrete, which causes concrete deterioration if value of pH is below 6. The purpose of this study is to investigate corrosion caused by acid rainfall when used PCC cement mixed with RHA. RHA replacement level of 5%, by weight of cement was used in this study. The compressive strength design was 30 MPa. The simulated acid rain solution was prepared by mixing solution of H2SO4 and HNO3 to reach value pH of 4. The deterioration was measured by the number of corrosion product using SEM test. The results indicate a decrease in the number of component corrosion that occurs by using ASP.

The relationships between concrete properties (strength, porosity, and carbonation) and time attacked by acid environment were studied. Current environmental condition with acid rain caused air, soil, and water is acidic. It threats the degradation building with concrete construction. Two groups were organized in this research. One of them which was defined as control specimen was immersed in water curing. The other one was immersed in a solution of 5% sulfuric acid (PH 3) for the purpose of simulating the acidic environment in the laboratory. Different from other reports, the cubes were not previously immersed in water for 28 days but directly immersed in acid solution after being demoulded for one day. Furthermore, the constitutional equations from laboratory experiment were validated by embedding the specimens in acid soil (real acid condition) with similar PH. The results showed that due to immersion in sulphuric acid 5%, concrete had a decreased strength, increased porosity and the occurrence of carbonation at the age of 3-90 days. The result from laboratory experiment for compressive strength was similar with that of a field experiment. Furthermore the relationship between the age of concrete and its porosity considered valid for the age of under 14 days. However, the relationship between the age of concrete and carbonation event judged invalid with that from a field experiment. The results established that the constitutive relations of the properties of concrete in the acid environment were considerably divided by the type of the acid environment.

This research is an experimental study of the properties of concrete blocks made from sugar mill waste. The properties that are reviewed are weight, water absorption, and compressive strength. The concrete blocks were made with five treatments for sand substitution with sugar mill waste (SMW) which were controls B0 (0%), B1 (6.25%), B2 (12.5%), B3 (18.75%) and B4 (25%) with a ratio of cement water of 0.4. Each treatment group was 30 samples so that the total sample was 150. The results showed that a high percentage of SMW caused a decrease in the weight of the blocks and increased water absorption. The addition of SMW on the aggregate affects the compressive strength of the blocks. A high percentage of SMW causes a decrease in the compressive strength of concrete blocks. The results of the statistical analysis showed that the addition of 12.5% SMW (B2) had an effect on the weight and absorption of the blocks, while the change in the compressive strength of the concrete block occurred with the addition of 6.25% SMW (B1).