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Beton sebagai material utama konstruksi sering mengalami panas hidrasi yang menyebabkan perbedaan suhu permukaan dengan suhu inti, akan berpotensi retak dini dan penurunan kuat tekan. Penelitian ini menganalisis potensi air es dan fly ash 10% substitusi semen untuk memperkecil suhu beton mutu 35 MPa dengan aditif tipe D (retarder) dan F (superplasticizer), serta pengaruhnya terhadap kuat tekan. Metode deskriptif menggunakan data sekunder mix design tiga variasi: non fly ash, fly ash 10% dan fly ash 10%+air es 10°C. Suhu beton segar diukur dengan thermogun/thermometer lalu kuat tekan uji silinder diameter 150x300 mm umur 7 hari dan 28 hari dengan total 18 benda uji. Hasil menunjukkan suhu beton segar non fly ash berada pada rentang normal, beton fly ash 10% turun 1-2°C (reaksi pozzolanik lambat yang mengurangi panas hidrasi dari C2S, C3S, dan C3A), beton fly ash 10% + air es turun 5-6°C. Kuat tekan 7 hari menunjukkan beton non fly ash 33,69 MPa, beton fly ash 10% 34,14 MPa, beton fly ash 10%+air es 34,73 MPa. Pada umur 28 hari menunjukkan beton non fly ash 39,73 MPa, beton fly ash 10% 39,80 MPa, dan beton fly ash 10%+air es 39,65 MPa – semua melebihi mutu rencana.

This study analyzes the potential use of cockle shell waste and coal fly ash as alternative raw materials in the production of composite brake pads. The high volume of industrial and fisheries waste, which has not been optimally utilized, encourages the exploration of environmentally friendly materials with adequate mechanical performance. The main focus of this research is the compressive strength of the produced brake pads, as this parameter is crucial for ensuring effective and safe braking performance. The method used includes the mixing and molding of composite materials with varying compositions of cockle shell and fly ash, followed by compressive strength testing according to standards. This study also takes into account the environmental impact of using waste as filler material, which is expected to reduce reliance on conventional materials and decrease waste that contaminates the environment. The results of the study are expected to provide empirical data on the potential of these two wastes as fillers in brake pad matrices and to identify the optimal formulation that provides the highest compressive strength. This study contributes to the development of sustainable braking materials and efforts to mitigate the environmental impact of waste, while also opening opportunities for the reuse of waste that has previously been poorly managed.

The durability of Self-Compacting Concrete (SCC) containing fly ash and Sika Viscocrete can be affected by exposure to seawater. This research investigates how seawater curing impacts the compressive strength of SCC modified with varying fly ash content and Sika Viscocrete admixture. The concrete mixtures were designed with 0% and 30% fly ash by cement weight and a constant 1% dosage of Sika Viscocrete. Compressive strength tests were conducted at 7, 14, and 28 days. The findings indicate that seawater curing has a notable effect on compressive strength, producing generally higher strength values than those cured in freshwater. Under freshwater conditions, strength increased steadily at 14 and 28 days, peaking at 54.1 MPa with 30% fly ash at 28 days. Conversely, the highest strength under seawater curing was achieved earlier, at 7 days, also with 30% fly ash, reaching 56.1 MPa. Overall, the optimum compressive strength was attained with a 30% fly ash mixture cured in seawater, suggesting this method enhances early-age strength in SCC.

This research utilizes waste from PLTU Tanjung Jati B Jepara, namely FABA (Fly ash Bottom Ash) as an alternative to fine and coarse aggregate. From this research, the physical properties of faba aggregate can be seen from the results of the faba aggregate sieve analysis test, which obtained a fineness modulus value of 1.74, which is included in the medium aggregate type. The water content of fine aggregate (fly ash) obtained a value of 3.63% and coarse aggregate (bottom ash) obtained a value of 1.5%. The fine aggregate sludge content (fly ash) obtained a value of 0%. The fine aggregate organic substance (fly ash) acquires a reddish brown NaOH color, therefore it must be washed before being used as a concrete mixture. The face dry specific gravity of fine aggregate (fly ash) obtained a value of 2.63 gr/cm2 and coarse aggregate 2.52 gr/cm2. From the data that has been obtained, faba aggregate is considered to have physical properties that meet the requirements for fine aggregate and can be used as a substitute for sand. The results of the final compressive strength of faba concrete and normal concrete at the age of 7 days and 28 days showed that the compressive strength of normal concrete (control) was higher than that of faba concrete. The standard deviation values ​​at the ages of 7 and 28 days are included in perfect working conditions because they have a standard deviation value of less than 3 MPa. From the results of the concrete flexural strength test, only the control concrete was 1;1.5 with a flexural strength of 4.18 MPa, which is close to SNI 2847:2013, namely with a minimum flexural strength of fs = 4.4 MPa. Normal concrete has a higher flexural strength than faba concrete. Based on tests carried out with the planned mix design, the 1:1.5 variation obtained the highest results.

This research is an experimental study on porous concrete and the use of fly ash as a binder for concrete to analyze the effect of compressive strength and porosity. The research method used in this study is the experimental method which is a research method used to find the effect of certain treatments on concrete. In this research, the concrete mix design uses a ratio of gravel and geopolymer paste as a binder, namely 4: 1 and uses a molarity ratio of 10M with differences in grading of coarse aggregate using sieves number 4, 1/2 ", and 3/8". The optimum compressive strength value was obtained in mix design 1 using sieve gradation no.4 which was 4.25 MPa at 28 days old. While the results of the highest porosity value were found in mix design 1 which was 7.15% at 28 days old

Coal is an organic mineral from ancient plant remains that settles and goes through physical or chemical processes over a period of up to millions of years. Coal is used as a source of steam-powered electrical energy through combustion which produces fly ash waste. fly ash contains various chemical materials such as SiO2; Al2O3; Fe2O3. The potential chemical content makes fly ash which can be used as an adsorbent for heavy metals and dyes by forming silica xerogel. To increase the silica oxide content in fly ash, a washing process is carried out with various solvents. Research on the adsorption of methylene blue dye using silica xerogel from fly ash with variations in contact time. The results showed that silica xerogel from fly ash was able to adsorb methylene blue dye at a contact time of 90 minutes. Adsorption kinetics follows a pseudo second order model with an R2 value that is better than pseudo first order. It can be seen that the R2 value respectively shows a linear regression of 0.703 for pseudo first order and 1 for pseudo second order.