Redbrick is one of the building materials which is commonly used as a basic building material. In the traditional red brick factory in the village of Singgahan Tuban, East Java, some problems are often encountered in the field, namely red bricks that are cracked and broken on the bricks at the bottom of the pile. This has an impact on results that are not on target. The purpose of this study was to determine the effect of wood sawdust and hydroton substitution on the compressive strength, density, and water absorption capacity of redbrick. Using an experimental method with a substitution ratio of wood sawdust and hydroton of 5%, 10%, and 15%. Manufacture of 50 red bricks measuring 23 x 11 x 4.5 cm. The drying process is carried out for 5 days then burned at 900° C for 2 days. From the test, it was found that the red brick without substitution had a compressive strength value of 8.95 MPa, a density value of 1.59 grams / cm³, and a water absorption capacity of 11.14%. The red brick substitution of wood sawdust waste has a compressive strength value of 6.25 MPa, a density value of 1.48 grams / cm³ and a water absorption capacity of 12.04%. In the red brick, the hydroton substitution has a compressive strength value of 9.27 MPa, a density value of 1.64 grams/cm air, and a water absorption capacity of 11.22%.

Wood management activities that are often encountered, as in wood cutting activities in the manufacture of wooden handicrafts, basically after this activity can become a problem, namely sawdust waste, where this waste if left for so long will be a big problem and have an impact on the environment. One solution that can be used for the problem of sawdust waste is to mix this sawdust waste into a concrete mixture. This sawdust waste can be used in concrete mixtures because of the cellulose content in sawdust waste which can affect the compressive strength value with different concrete treatment methods (curing) and slump of concrete. In this research included into experimental research with wood used is wood kamper samarinda, from the leftover cutting of wood frames from craftsman wood UD. kembang Arum in Bekasi, West Java.  Using sawdust waste with a size that passes through sieve No.4 (passes through a 4.75 mm) with variaes addition of 0 kg/m3 , 1 kg/m3  dan 1,5 kg/m3, as well as testing with a concrete mixture that has a mix design of 35 MPa f'c which is inserted into the test object in the form of a cylinder with a diameter and height of 15 and 30 cm which is then for the treatment method done by three different methods. The addition of saw dust waste with a varies of 1 kg/m3  dan 1,5 kg/m3   to the concrete mixture makes the slump and workability values decrease, but the slump value obtained is still in accordance with slump value plan. and for compressive strength values with an addition variation of 1 kg / m3 and 1.5 kg / m3 , The compressive strength value changes from the normal compressive strength value of concrete and the effect of the treatment method also affects the compressive strength value obtained.

Karst regions in Indonesia have the uniqueness of the landscape and biodiversity. The karst is formed by the dissolution of rocks and the precipitation of mineral. In the cave, there are ornaments of stalactite and stalagmite which are formed by the process of mineral precipitation. We have isolated, screened, and identified the soil bacterium from the cave environment (Lysinibacillus macroides). These bacteria are able to precipitate calcium carbonate and can be developed as a self-healing agent concrete. We investigated the proportions and the properties of mixtures concrete containing lightweight aggregate and volcanic ash impregnated with bacteria. A comparison study was made by concrete cylinders subjected to compressive strength tests with and without the bacteria. It found that the strength of concrete with bacteria decreased by less than 10.56% for 28 days of cured specimens. This study showed that the effects of bacteria on the strength of concrete are not considerable. However, these bacteria are effective to repair in the microcrack less than 0.3 mm

The utilization of waste as soil stabilization materials is a solution to reduce the amount of waste and improve the building materials quality. This research is using Spent Bleaching Earth (SBE) materials from the palm oil industry waste. SBE can be reused to be pozzolan materials. This research aimed to investigate the SBE waste effect as an admixture on clay stabilization used 10% Clean Set Cements (CS-60) on density and California Bearing Ratio (CBR). A combination of CS-60 and SBE waste was expected to increase the CBR value of clay. Furthermore, SBE waste would decrease cementitious material for clay stabilization. Variation comparison of Clay : CS-60 : SBE on ST03, ST04, and ST05 were 67.5% : 10% : 22.5%; 45% : 10% : 45% and 22.5% : 10% : 67.5% respectively. The test was conducted on water content, density, and load penetration based on SNI 1744:2012. Generally, the CBR value of subgrade and improved subgrades oil with the moderate and good category are about 5-20%. As a result, the CBR value of ST 01 as original clay and ST 02 as clay with 10% CS-60 was 3.24% and 5.01%, respectively. Using SBE waste as an admixture material on clay stabilization increased CBR value better than clay stabilization used CS-60. ST03, ST04, and ST05 with CBR's value were 5.39%, 8.52%, and 17.99%, respectively. Furthermore, the density value decreased when SBE waste is used. Keywords : california bearing ratio, clay, clean set cement, spent bleaching earth, stabilization.   ABSTRAK Pemanfaatan limbah sebagai bahan stabilisasi tanah lempung merupakan solusi dalam mengurangi jumlah limbah dan meningkatkan mutu dari bahan bangunan. Penelitian ini menggunakan material Spent Bleaching Earth (SBE) dari limbah industri pengolahan minyak kelapa sawit. SBE dapat dimanfaatkan sebagai material pozzolan. Penelitian ini bertujuan untuk mengetahui pengaruh limbah SBE sebagai bahan tambah pada stabilisasi tanah lempung yang menggunakan 10% Clean Set Cements (CS-60) terhadap densitas dan California Bearing Ratio (CBR). Kombinasi limbah SBE dengan CS-60 diharapkan mampu meningkatkan nilai CBR tanah lempung. Selain itu, juga mengurangi penggunaan bahan berbasis semen untuk stabilisasi tanah lempung. Variasi perbandingan tanah lempung : CS-60 : SBE yang digunakan pada sampel ST03, ST04, dan ST05 berturut-turut 67,5% : 10% : 22,5%, 45% : 10% : 45% dan 22,5% : 10% : 67,5%. Pengujian yang dilakukan meliputi pengujian kadar air, densitas, dan penetrasi beban yang mengacu pada SNI 1744:2012. Secara umum, nilai CBR tanah dasar dan tanah timbunan dengan kategori sedang dan baik berkisar antara 5-20%. Hasil penelitian ini memperlihatkan bahwa sampel ST01 yang berupa tanah lempung asli memiliki nilai CBR 3,24% dan sampel ST02 yang berupa tanah lempung yang distabilisasi dengan 10% CS-60 menghasilkan nilai CBR 5,01%. Penambahan limbah SBE dapat meningkatkan nilai CBR dengan nilai yang lebih tinggi bila dibanding dengan hanya distabilisasi dengan CS-60, hal ini terlihat pada sampel ST03, ST04, dan ST05 dengan nilai CBR berurutan sebesar 5,39%, 8,52%, dan 17,99%. Selain itu, penambahan limbah SBE juga akan menurunkan densitas dari tanah lempung.   Kata kunci : california bearing ratio, clean set cement, spent bleaching earth, stabilisasi, tanah lempung.

The purpose of this study was to determine the effect of utilizing fly ash and chicken egg shell powder on the compressive strength of concrete, workability, density and water absorption. In this study, testing was carried out with the use of fly ash waste and chicken egg shell powder with variations of 15% fly ash waste and variations of chicken egg shell powder by 10% and 17.5% at the age of 3 days, 7 days, 14 days, and 28 days. for the test objects used measuring with a diameter of 10 cm and a height of 20 cm as many as 36 test samples by making variations of the day as many as 3 samples of test objects. Concrete with a mixture of 15% Fly Ash waste and 10% Egg Shell Powder in test sample 2 obtained a compressive strength at the age of 28 days of 29.45 Mpa. Variation of the Normal Concrete sample got a compressive strength at the age of 28 days of 30.37 MPa. Variation of test sample 3 got a compressive strength at the age of 28 days of 21.16 Mpa.