Effects of powdered glass as an admixture in cement concrete block

This paper investigated the effects of glass usage in finely divided form on the properties of cement concrete. The powdered glass was used as admixture, replacing cement in the concrete production process. The sourced glass were washed and dried for some days. The dried glass was then crushed into smaller pieces before grinding to finely divided form. Replacement of cement with powdered glass was done at 0-10% with 2% increment by weight of cement. Using a design mix of 1:2:4, with a constant water cement ratio of 0.6, the workability of fresh specimens were determined using the slump height procedure. The specimens were then poured in 150x150x150mm steel moulds and left for 24 hours. The hardened concrete specimens were cured by complete immersion in water for 7, 14, 21 and 28 days. The result showed that workability increases with increase in admixture content. It further revealed that the compressive strength increases with admixture addition to about 4% powdered glass addition. The compressive strength at 6% addition of powdered glass was also higher than that of the conventional concrete. Thus replacement can be done to about 6% addition of powdered glass by weight of cement. The models developed from the study corroborated well with experimental values as high coefficient of determination values were obtained. The models can thus, be used to predict the compressive strength of powdered glass-cement concrete.Keywords: Admixture, Cement Concrete, Compressive Strength, Slump, Powdered Glas

Effect of low density polyethylene as bitumen modifier on some properties of hot mix asphalt

In Nigeria today, polyethylene or water sachet is a major environmental pollutant, a nonbiodegradable material. The usefulness of this pollutant (polyethylene) in the highway industry was investigated by studying its effects on some selected properties of Hot Mix Asphalt, such as, bulk density, stability and flow of the asphalt concrete mix. Specimen preparation was done using Marshall Mix design procedure. The optimum binder content was determined as 5.20% and three samples each for five variations of polyethylene content (2%, 4%, 6%, 8% and 10%) by weight of optimum binder content. It was observed from the study, that the stability and density of asphalt increased with polyethylene content, while a linear reduction in the flow and penetration values was observed with polyethylene content. The optimum modifier content value of 8% by weight of the optimum bitumen content. Models were also developed whose predictive values corroborated well with experimental values with acceptable coefficient of correlation values. Bitumen modified with polyethylene improved the engineering properties of asphalt which therefore means that usage of this waste product in the asphalt production for roadwork is an effective and economical way of managing this waste.Keywords: Polyethylene, modifier, asphalt, bitume

Characteristics of almond leaf-ash cement stabilized lateritic soil

The use of Almond leaf-ash for stabilization purposes has not been given consideration. This paper was thus aimed at evaluating the characteristics of almond leaf-ash for the essence of stabilizing lateritic soil. Sourced lateritic soil was divided into 3 components (unmodified soil sample, cement stabilized soil sample and almond leaf-ash cement stabilized soil sample). Almond leaves were calcined at 250°C and subjected to granulation process. Preliminary tests such as; sieve analysis, Atterberg’s limit and specific gravity tests were done on the unmodified soil sample for the purpose of classification. CBR tests were performed on the cement stabilized soil sample and on the almond leaf-ash cement stabilized lateritic soil sample. A model was developed using the Scheffe’s simplex theory with the cement component fixed at 10% of the dry lateritic soil. Results revealed that the soil was observed to be a Silty Clay soil (A-4) with Plasticity index of 9.24%, therefore requiring stabilization. CBR results for the developed trial mixes were greater than the 15.20% obtained for 10% cement stabilization showing that Almond leaf-ash significantly improved the CBR of the cement stabilized lateritic soil. The CBR model developed for the Almond leaf-ash cement soil also proved adequate from the verification test conducted using χ2 statistics. Keywords: Almond Leaf Ash, stabilization, California Bearing Ratio, Scheffe’s theory, lateritic soil