 alternative aggregates in the cement block making process alternative aggregates in the cement block making process recycled plastic bottles in the blockmaking process ms tajwattie persaud a student of the faculty of earth and environmental sciences has investigated the impact on the compressive strength of hollow concrete blocks hcbs when plastic bottle flakes are integrated as a partial substitute for sand it should be noted that in guyana there is little to no resource recovery practices done for the management of plastic bottle wastes this leads to the pollution of streets water bodies and the surrounding environment posing the risk of flooding degradation of land and marine species all of which adversely affect the health of both humans and the environment for her research project ms persaud collected more than 60 garbage bags of plastic bottles from two communities parfait harmony community and plastic city in vreedenhoop as part of a cleanup drive a significant amount of the plastic bottles was recycled for use in this experiment with the remainder being diverted to landfill the research process involved having the plastic bottles washed and hand chipped into flakes before being added into the modified cement mix at ratios of 5 and 10 percent the ten percent hcbs met the requirements of the guyana national bureau of standards gnbs for compressive strength and was certified for use in building construction ms persaud expressed confidence that if a project of this nature is given the necessary support to expand on a much larger scale it could be very successful on various fronts including providing entrepreneurial opportunities reducing the level of plastic wastes that pollute our environment and lowering the overhead costs for producing hcbs by replacing some amount of sand with recycled bottles the innovator is hoping to embark on an awareness campaign that will seek to educate persons about the project so that they will understand the rationale behind using recycled plastic bottles to reduce the amount of sand needed in the block making process while at the same time addressing the issue of reducing the amount of wastes that goes into the environment  rice husk and rice husk ash in the cement block making process lecturer isidro espinosa attached to the faculty of engineering and technology is in the preliminary stages of creating concrete with rice husk and rice husk ash as a substitute for sand in the concrete block making process he explained rice husk is a byproduct of the milling process and can be considered as a resource rather than a waste product guyana produced more than 1 million tons of paddy in 2019 gbti 2020 with its average equivalent in rice husk being about 200000 metric tons the innovator stated that rice husk can replace up to 30 of sand aggregate in the concrete making process since 8090 of rice husk contains silicates which is the main component of sand silica sand the benefits of using rice husk and rice husk ash include zero waste output value is added to rice husk reduction in cost from raw materials in the construction industry the preliminary test shows that the utilisation of rice husk and rice husk ash as a component in concrete block or brick making allows for buildings to improve thermal insulation for hot climates like guyana it also gives buildings a soundproof effect  sawdust in blockmaking process the project is being led by mr mark austin a student within the department of forestry faculty of agriculture and mr ewart smith a lecturer at ug and current phd candidate at trent university it aims to utilise sawdust waste which is an environmental hazard to make cement blocks the objective of the project is to compare the rate of water absorption properties and compressive properties of sawdust blocks to determine their suitability for use in construction dean of the faculty of the agriculture and forestry dr lawrence lewis explained that the project seeks to vary the ratio of the sawdust and the size of the sawdust to determine which can produce a composite block the project also utilises pretreated sawdust removing the resin out of the wood which can inhibit the mixing and combining process of the sawdust the blocks have met the astm standards for compressive strength and water holding capacity andydindial tue 2142023 1047  