Time overrun in construction projects is a very serious issue in developed countries. The main object of this research is to find the main causes of time overrun in the construction of building project and its possible mitigation measures. Quantitative approach was adopted in this research to achieve object and RIW (relative importance weight) approach was used for collecting data. Financial issues faced by the contractor, contractor’s inexperience, weather impacts, late delivery of material, mistakes in design, shortage of skilled labor, incompetent subcontractor and mistakes in time estimation were identified as main causes of time overrun in construction projects and possible mitigation measures were also proposed from experts. This research will help in giving awareness to stakeholders to narrow down the factors of time overrun in construction projects in Pakistan.

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Cement as a binder used in the mixture of concrete is a costly product and it is also harmful to the environment due to the emission of huge amounts of CO2 and other gases. Like cement the fine aggregate is also the main constituent of the concrete used as inert filler in concrete is also expensive. The researchers are probing towards the new inexpensive and environment friendly materials for the concrete. They have agreed over the point that by utilizing the recycled waste materials could be helpful in achieving the sustainable construction. So in this case a lot of research has been carried out for the utilization of rice husk ash as cement substitution and recycled waste glass as alternative of concrete fine aggregate. The outcome of this research is that these both green materials have enormous potential to contribute in the long-lasting   handling of ineffectual solid waste, reduction of landfill sites, preserving natural resources and protecting atmosphere from extremely hazardous gases. The purpose of this review work is to summarize the previous research findings on utilization of rice husk ash and recycled waste glass as a substitution to the cement and fine aggregate respectively. This review paper will come up with the remarkable idea and valuable information for the upcoming researchers working for the aim of utilization of renewable and futile  materials in the field of concrete technology.

This study focused on the recycling of Glass Waste (GW) and Ceramic Tile Waste (CTW) in the concrete. However, GW was considered as fine aggregate replacement and CTW was considered as coarse aggregate replacement in the concrete. The concrete of grade 20 (M20) was prepared in the laboratory with various proportions of waste materials. The GW was introduced with 5%, 10%, and 15% replacement of fine aggregates, and CTW was incorporated with 10%, 20% and 30% replacement of coarse aggregates in the concrete. After that, fresh mix and hardened properties of concrete were evaluated. It was noticed that the with increases the partial replacement of GW as FA slump value increases. Glass waste particles absorbed less water as compared to natural FA and thus improving the workability of concrete. Based on the compressive strength results of 28days the optimum replacement was noticed as fine aggregate with 10% GW and coarse aggregate with 20% CTW. However, combined use of both wastes materials could not improves the strength performances of concrete significantly.

The Recycled Waste Glass (RWG) is a most suitable substitute to the natural sand to be utilized in the concrete manufacturing industryand Rice Husk Ash (RHA) is an agricultural by-product having enormous characteristicsto utilize as cementitious material in concrete. This study was carried out to understand the effects of RHA as partial replacement to cement and RWG as a partial replacement to natural fine aggregate with 10%, 20% and 30% levels of substitutions in the concrete mixes respectively. The effects were investigated on the workability and compressive strength characteristics of fresh and hardened concrete. A total of 4 mixtures were prepared for M15 grade concrete with 1:2:4 concrete proportions and water to cement ratio of 0.55. Out of them one was controlled mixture and three were with 10%, 20% and 30% equal substitution levels of combined RHA and RWG. The acquired results showed that the slump values were like that of conventional concrete at combined incorporation of RHA and RWG at 10% replacement, but a decline was noticed at 20% and 30% replacement. The decline was due to the more surface area of RHA which absorbs more water. The compressive strength at 10%RHA and 10% RWG combined replacement in concrete mix was increased by 9.7% as compared to controlled mix after 28 days curing. The results were similar at 20%RHA and 20%RWG incorporation as compared to controlled concrete mix. It is concluded that RHA and RGW can be utilized at 10% equal replacement in the concrete and the cost of construction can be reduced. This research work will be helpful in developing a comprehensive scientific data base on combined utilization of RHA and RWG in the concrete mixes and the upcoming scientists, scholars and students will be benefitted.