Abstract. This paper presents compressive strength and water penetration of bioconcrete with addition of calcium lactate. Bioconcrete has higher engineering concrete properties and durability compared to normal concrete but the natural production of calcium carbonate is limited to the calcium content in cement. Therefore, additional calcium is added as an additional calcium source to study the influence towards compressive strength and water penetration. The bacteria used in this research are Enterococcus faecalis and Bacillus sp. Calcium lactate was added into concrete mix in concentrations of 0.001mol/l, 0.005mol/l and 0.01mol/l of liquid used. The concentration of bacteria added into the mix is by partial replacement of water used in casting, which are 3% for Enterococcus faecalisand 5% for Bacillus sp. Both compressive strength and water penetration test used cubes of 150mm × 150mm × 150mm. The cubes were tested after 28 days. The result of compressive strength for control is 36 MPa while partial replacement of bacteria yields 38.2 MPa for 3% Enterococcus faecalisand 37.0 MPa for 5% Bacillus sp. Calcium lactate with 0.005 mol/L has the best performance with 42.8 MPa for Enterococcus faecalis and 39.6 MPa for Bacillus sp. Whereas for water penetration, the best concentration of calcium lactate which yielded the lowest water penetration is 0.01 mol/l for both Enterococcus faecalis and Bacillus sp which are 8.7 cm and 8 cm respectively. The addition of calcium lactate into bioconcrete is quite promising for improvement of concrete properties and durability.

Abstract. Interlocking Compressed Earth Block (ICEB) are cement stabilized soil blocks that allow for dry stacked construction. Because of this characteristic, the process of building walls is faster and requires less skilled labour as the blocks are laid dry and lock into place. However there are plenty room for improving the interlocking blocks by increase its durability. Durability of bricks are affected by several factors and one of them are water absorption. High water absorption level will results in low durability. Many studies have been conducted in order to improve the durability of bricks by using environmentally method. One of the method is by inducing bacteria into bricks. Bacteria in brick induced calcite precipitation (calcite crystals) to cover the cracks continuously. Therefore, the issues of durability of bricks can be fully solved. This paper offer a review on interlocking compressed earth blocks and the use of bacteria in reducing water absorption level.

Abstract. The emission of CO 2 into atmosphere which has increased rapidly in the last years has led to global warming. Therefore, in order to overcome the negative impacts on human and environment, the researchers focused mainly on the reduction and stabilization of CO 2 which represent the main contributor in the increasing global warming. The natural capturing and conversion of CO 2 from atmosphere is taken place by biological, chemical and physical processes. However, these processes need long time to cause a significant reduction in CO 2 . Recently, scientists shifted to use green technologies that aimed to produce concrete with high potential to adsorb CO 2 in order to accelerate the reduction of CO 2 . In the present review the potential of bio-concrete to sequestrate CO 2 based on carbonation process and as a function of carbonic anhydrase (CA) is highlighted. The factors affecting CO 2 sequestration in concrete and bacterial species are discussed. It is evident from the literatures, that the new trends to use bio-concrete might contribute in the reduction of CO 2 and enhance the strength of non-reinforced concrete.

Abstract. Interlocking compressed earth blocks (ICEB) are soil stabilized based blocks that allows for mortarless construction. Various studies have been conducted to improve the durability of bricks by using environmental friendly solution. This is because common method used by the construction industries generally involving the use of chemical based substances which will promote pollution to the surrounding. This paper provide the results of Ureolytic Bacteria (UB) in improving the compressive strength and water absorption properties with the percentage of 1%, 3% and 5% UB for 7 th ,14 th and 28 th days of testing. The bacteria were added as partial replacement of limestone water in ICEB. The results of compressive strength and water absorption show that the increment of 15.25% strength and reduction of 15.66% water absorption with 5% of UB on the 28 th days of testing compared to the control specimen. Therefore it is hoped that the positive results on using bacteria will continue to improve the durability of the ICEB as one of the environmental friendly solution in order to achieve sustainable construction.

No abstract